# Selected Cylc Changes

Internal changes that do not directly affect users may not be listed here.  For
all changes see the [closed
milestones](https://github.com/cylc/cylc-flow/milestones?state=closed) for each
release.

## Backward-incompatible changes in Cylc-8.x

Cylc 8.0aX (alpha) releases are not compatible with Cylc 7 or with previous
8.0aX releases, as the API is still under heavy development.

The Cylc server program and CLI codebase is now a Python 3 package that can be
installed from PyPI with `pip` (see
[#2990](https://github.com/cylc/cylc-flow/pull/2990)), and has been renamed to
`cylc-flow`. The name `cylc` is now used as a native Python package namespace
to allow other projects to re-use it and extend Cylc with plug-ins.

The old PyGTK GUI is being replaced by a Web UI, with development managed in
the cylc/cylc-ui repository (and see also cylc/cylc-uiserver).

The User Guide and other documentation has been removed from the Python package
to the cylc/cylc-doc repository.

The commands `cylc-profile-battery`, `cylc-test-battery`, `cylc-license`
have been removed, and `cylc graph` is only retained for text output
used in tests (it will be re-implemented in the new web UI).

The xtrigger examples were moved to a separate `cylc/cylc-xtriggers` project
(see [#3123](https://github.com/cylc/cylc-flow/pull/3123)).

Jinja filters were moved from its `Jinja2Filters` folder to within the `cylc`
namespace, under `cylc.jinja.filters`.

Cylc Review was also removed in this version.

Cylc 7 suites cannot be *restarted* (from previous state) with Cylc 8, but they
can still be started from scratch
([#3863](https://github.com/cylc/cylc-flow/pull/3863)).

Named checkpoints have been removed ([#3906](https://github.com/cylc/cylc-flow/pull/3906))
due to being a seldom-used feature. Workflows can still be restarted from the
last run, or reflow can be used to achieve the same result.

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-------------------------------------------------------------------------------
## __cylc-8.0b3 (<span actions:bind='release-date'>Released 2021-11-10</span>)__

Fourth beta release of Cylc 8.

`suite owner` and `workflow owner` option option has been removed.

(See note on cylc-8 backward-incompatible changes, above)

### Enhancements

[#4367](https://github.com/cylc/cylc-flow/pull/4367) -
Make the central wrapper work with arbitrary virtual environment names.

[#4343](https://github.com/cylc/cylc-flow/pull/4343) -
Implement required and optional outputs with new graph notation.

[#4324](https://github.com/cylc/cylc-flow/pull/4324) -
Re-implement a basic form of the Cylc 7 `cylc graph` command for static
graph visualisation.

[#4335](https://github.com/cylc/cylc-flow/pull/4335) -
Have validation catch erroneous use of both `expr => bar` and `expr => !bar` in
the same graph.

[#4285](https://github.com/cylc/cylc-flow/pull/4285) - Cylc now automatically
infers the latest numbered run of the workflow for most commands (e.g. you can
run `cylc pause foo` instead of having to type out `foo/run3`).

[#4346](https://github.com/cylc/cylc-flow/pull/4346) -
Use natural sort order for the `cylc scan --sort` option.

[#4313](https://github.com/cylc/cylc-flow/pull/4313) - Change `ignore` to
`reload` for the cycle point cli options (e.g. `--fcp=reload`), as this more
accurately reflects what it's doing. Also improve validation of these
cli options.

[#4389](https://github.com/cylc/cylc-flow/pull/4389) - the `flow.cylc.processed`
(previously called `suite.rc.processed`) is now stored in `log/flow-config/`.

[#4329](https://github.com/cylc/cylc-flow/pull/4329) - Enable selection of
platform from platform group at task job initialization.

[#4430](https://github.com/cylc/cylc-flow/pull/4430) - Log files renamed:
- `log/flow.cylc.processed` ⇒ `log/flow-processed.cylc`
- `log/<datetimes>-run.cylc` ⇒ `log/<datetimes>-start.cylc`

[#4423](https://github.com/cylc/cylc-flow/pull/4423) - Only changes to the
workflow directory are recorded by `log/version`.

[#4404](https://github.com/cylc/cylc-flow/pull/4404) - The Cylc Graph section
now accepts ``&`` and ``|`` as valid line breaks in the same way as ``=>``.

[#4455](https://github.com/cylc/cylc-flow/pull/4455) - `CYLC_WORKFLOW_NAME`
renamed to `CYLC_WORKFLOW_ID`. `CYLC_WORKFLOW_NAME` re-added as
`CYLC_WORKFLOW_ID` shorn of any trailing `runX`.

[#4457](https://github.com/cylc/cylc-flow/pull/4457) - Cylc 8
`cycle point time zone` now defaults to UTC, except in Cylc 7 compatibility mode.


### Fixes

[#4493](https://github.com/cylc/cylc-flow/pull/4493) - handle late job
submission message properly.

[#4443](https://github.com/cylc/cylc-flow/pull/4443) - fix for slow polling
generating an incorrect submit-failed result.

[#4436](https://github.com/cylc/cylc-flow/pull/4436) -
If the workflow is paused, hold tasks just before job prep.
Distinguish between succeeded and expired state icons in `cylc tui`.
Spawn parentless tasks out the runahead limit immediately.

[#4421](https://github.com/cylc/cylc-flow/pull/4421) -
Remove use of the `ps` system call (fixes a bug reported with Alpine Linux).

[#4426](https://github.com/cylc/cylc-flow/pull/4426) -
Fix bug when a conditional expression in the graph contains one task name that
is a substring of another.

[#4399](https://github.com/cylc/cylc-flow/pull/4399) -
Ensure that implicit task names are validated (as opposed to explicit ones).

[#4341](https://github.com/cylc/cylc-flow/pull/4341) -
Remove obsolete Cylc 7 `[scheduling]spawn to max active cycle points` config.

[#4319](https://github.com/cylc/cylc-flow/pull/4319) -
Update cylc reinstall to skip cylc dirs work and share

[#4289](https://github.com/cylc/cylc-flow/pull/4289) - Make `cylc clean`
safer by preventing cleaning of dirs that contain more than one workflow
run dir (use `--force` to override this safeguard).

[#4362](https://github.com/cylc/cylc-flow/pull/4362) -
When using `cylc clean` on a sequential run directory, remove the `runN` symlink
if it points to the removed directory.

[#4395](https://github.com/cylc/cylc-flow/pull/4362) -
Fix ``cylc stop --kill`` which was not actually killing task jobs.

[#4338](https://github.com/cylc/cylc-flow/pull/4338) - Cylc install -C option
now works with relative paths.

[#4440](https://github.com/cylc/cylc-flow/pull/4440) -
Fix an error that could occur during remote clean and other `cylc clean`
improvements.

[#4481](https://github.com/cylc/cylc-flow/pull/4481) -
Removed non-functional ping command from GUI.

[#4445](https://github.com/cylc/cylc-flow/pull/4445) - Cylc will prevent you
using the same name for a platform and a platform group. Which one it should
pick is ambiguous, and is a setup error.

[#4465](https://github.com/cylc/cylc-flow/pull/4465) -
Fix a `ValueError` that could occasionally occur during remote tidy on
workflow shutdown.

-------------------------------------------------------------------------------
## __cylc-8.0b2 (<span actions:bind='release-date'>Released 2021-07-28</span>)__

Third beta release of Cylc 8.

(See note on cylc-8 backward-incompatible changes, above)

### Enhancements

[#4286](https://github.com/cylc/cylc-flow/pull/4286) -
Add an option for displaying source workflows in `cylc scan`.

[#4300](https://github.com/cylc/cylc-flow/pull/4300) - Integer flow labels with
flow metadata, and improved task logging.

[#4291](https://github.com/cylc/cylc-flow/pull/4291) -
Remove obsolete `cylc edit` and `cylc search` commands.

[#4284](https://github.com/cylc/cylc-flow/pull/4284) -
Make `--color=never` work with `cylc <command> --help`.

[#4259](https://github.com/cylc/cylc-flow/pull/4259) -
Ignore pre-initial dependencies with `cylc play --start-task`

[#4103](https://github.com/cylc/cylc-flow/pull/4103) -
Expose runahead limiting to UIs; restore correct force-triggering of queued
tasks for Cylc 8.

[#4250](https://github.com/cylc/cylc-flow/pull/4250) -
Symlink dirs localhost symlinks are now overridable with cli option
`--symlink-dirs`.

[#4218](https://github.com/cylc/cylc-flow/pull/4218) - Add ability to
start a new run from specified tasks instead of a cycle point.

[#4214](https://github.com/cylc/cylc-flow/pull/4214) -
Unify `-v --verbose`, `-q --quiet` and `--debug` options.

[#4174](https://github.com/cylc/cylc-flow/pull/4174) - Terminology: replace
"suite" with "workflow".

[#4177](https://github.com/cylc/cylc-flow/pull/4177) - Remove obsolete
configuration items from `global.cylc[platforms][<platform name>]`:
`run directory`, `work directory` and `suite definition directory`. This
functionality is now provided by `[symlink dirs]`.

[#4142](https://github.com/cylc/cylc-flow/pull/4142) - Record source directory
version control information on installation of a workflow.

[#4238](https://github.com/cylc/cylc-flow/pull/4238) - Future tasks can now
be held in advance using `cylc hold` (previously it was only active tasks
that could be held).

[#4237](https://github.com/cylc/cylc-flow/pull/4237) - `cylc clean` can now
remove specific sub-directories instead of the whole run directory, using the
`--rm` option. There are also the options `--local-only` and `--remote-only`
for choosing to only clean on the local filesystem or remote install targets
respectively.

### Fixes

[#4296](https://github.com/cylc/cylc-flow/pull/4296) -
Patches DNS issues with newer versions of Mac OS.

[#4273](https://github.com/cylc/cylc-flow/pull/4273) -
Remove obsolete Cylc 7 visualization config section.

[#4272](https://github.com/cylc/cylc-flow/pull/4272) - Workflow visualisation
data (data-store) now constrained by final cycle point.

[#4248](https://github.com/cylc/cylc-flow/pull/4248) -
Fix parameter expansion in inherited task environments.

[#4227](https://github.com/cylc/cylc-flow/pull/4227) - Better error messages
when initial cycle point is not valid for the cycling type.

[#4228](https://github.com/cylc/cylc-flow/pull/4228) - Interacting with a
workflow on the cli using `runN` is now supported.

[#4193](https://github.com/cylc/cylc-flow/pull/4193) - Standard `cylc install`
now correctly installs from directories with a `.` in the name. Symlink dirs
now correctly expands environment variables on the remote. Fixes minor cosmetic
bugs.

[#4199](https://github.com/cylc/cylc-flow/pull/4199) -
`cylc validate` and `cylc run` now check task/family names in the `[runtime]`
section for validity.

[#4180](https://github.com/cylc/cylc-flow/pull/4180) - Fix bug where installing
a workflow that uses the deprecated `suite.rc` filename would symlink `flow.cylc`
to the `suite.rc` in the source dir instead of the run dir. Also fixes a couple
of other, small bugs.

[#4222](https://github.com/cylc/cylc-flow/pull/4222) - Fix bug where a
workflow's public database file was not closed properly.

-------------------------------------------------------------------------------
## __cylc-8.0b1 (<span actions:bind='release-date'>Released 2021-04-21</span>)__

Second beta release of Cylc 8.

(See note on cylc-8 backward-incompatible changes, above)

### Enhancements

[#4154](https://github.com/cylc/cylc-flow/pull/4154) -
Deprecate `CYLC_SUITE_DEF_PATH` with `CYLC_SUITE_RUN_DIR` (note the deprecated
variable is still present in the job environment).

[#4164](https://github.com/cylc/cylc-flow/pull/4164) -
Replace the job "host" field with "platform" in the GraphQL schema.

### Fixes

[#4169](https://github.com/cylc/cylc-flow/pull/4169) -
Fix a host ⇒ platform upgrade bug where host names were being popped from task
configs causing subsequent tasks to run on localhost.

[#4173](https://github.com/cylc/cylc-flow/pull/4173) -
Fix the state totals shown in both the UI and TUI, including incorrect counts
during workflow run and post pause.

[#4168](https://github.com/cylc/cylc-flow/pull/4168) - Fix bug where any
errors during workflow shutdown were not logged.

[#4161](https://github.com/cylc/cylc-flow/pull/4161) - Fix bug in in `cylc install`
where a workflow would be installed with the wrong name.

[#4188](https://github.com/cylc/cylc-flow/pull/4188) - Fix incorrect usage
examples for `cylc install`.

-------------------------------------------------------------------------------
## __cylc-8.0b0 (<span actions:bind='release-date'>Released 2021-03-29</span>)__

First beta release of Cylc 8.

(See note on cylc-8 backward-incompatible changes, above)

The filenames `suite.rc` and `global.rc` are now deprecated in favour of
`flow.cylc` and `global.cylc` respectively
([#3755](https://github.com/cylc/cylc-flow/pull/3755)). For backward
compatibility, the `cylc run` command will automatically symlink an existing
`suite.rc` file to `flow.cylc`.

Obsolete *queued* task state replaced by *waiting*, with a queued flag;
queueing logic centralized.
([#4088](https://github.com/cylc/cylc-flow/pull/4088)).

`cylc register` has been replaced by `cylc install`
([#4000](https://github.com/cylc/cylc-flow/pull/4000)).

Added a new command: `cylc clean`, for removing stopped workflows on the local
and any remote filesystems ([#3961](https://github.com/cylc/cylc-flow/pull/3961),
[#4017](https://github.com/cylc/cylc-flow/pull/4017)).

`cylc run` and `cylc restart` have been replaced by `cylc play`, simplifying
how workflows are restarted
([#4040](https://github.com/cylc/cylc-flow/pull/4040)).

`cylc pause` and `cylc play` are now used to pause and resume workflows,
respectively. `cylc hold` and `cylc release` now only hold and release tasks,
not the whole workflow. ([#4076](https://github.com/cylc/cylc-flow/pull/4076))

"Implicit"/"naked" tasks (tasks that do not have an explicit definition in
`flow.cylc[runtime]`) are now disallowed by default
([#4109](https://github.com/cylc/cylc-flow/pull/4109)). You can allow them by
setting `flow.cylc[scheduler]allow implicit tasks` to `True`.

### Enhancements

[#4119](https://github.com/cylc/cylc-flow/pull/4119) - Reimplement ssh task
communications.

[#4115](https://github.com/cylc/cylc-flow/pull/4115) - Raise an error when
invalid sort keys are provided clients.

[#4105](https://github.com/cylc/cylc-flow/pull/4105) - Replace the
`cylc executable` global config setting with `cylc path`, for consistency with
`cylc` invocation in job scripts.

[#4014](https://github.com/cylc/cylc-flow/pull/4014) - Rename "ready" task
state to "preparing".

[#4000](https://github.com/cylc/cylc-flow/pull/4000) - `cylc install` command
added. Install workflows into cylc run directory from source directories
configured in `global.cylc` (see [#4132](https://github.com/cylc/cylc-flow/pull/4132)),
or from arbitrary locations.

[#4071](https://github.com/cylc/cylc-flow/pull/4071) - `cylc reinstall` command
added.

[#3992](https://github.com/cylc/cylc-flow/pull/3992) - Rename
batch system to job runner.

[#3791](https://github.com/cylc/cylc-flow/pull/3791) - Support Slurm
heterogeneous jobs with a special directive prefix.

[#3974](https://github.com/cylc/cylc-flow/pull/3974) - Template variables,
both in set files and provided via the -s/--set command line options are
now parsed using ast.literal_eval. This permits non-string data types,
strings must now be quoted.

[#3811](https://github.com/cylc/cylc-flow/pull/3811) - Move from cycle based
to `n` distance dependency graph window node generation and pruning of the
data-store (API/visual backing data). Ability to modify distance of live
workflow via API, with default of `n=1`.

[#3899](https://github.com/cylc/cylc-flow/pull/3899) - CLI changes
* Commands no longer re-invoke (so you get `cylc run` not `cylc-run`).
* Improve CLI descriptions and help.
* Internal-only commands now hidden from help.
* New entry point for defining Cylc sub-commands.
* remove `cylc check-software` (use standard tools like pipdeptree)
* remove `cylc nudge` (no longer needed)

[#3884](https://github.com/cylc/cylc-flow/pull/3884) - Directories `run`,
`log`, `share`, `share/cycle`, `work` now have the option to be redirected to
configured directories by symlink.

[#3856](https://github.com/cylc/cylc-flow/pull/3856) - fail the GraphQL query
with a helpful message if the variables defined do not match the expected
values.

[#3853](https://github.com/cylc/cylc-flow/pull/3853) - Update protobuf and
pyzmq.

[#3857](https://github.com/cylc/cylc-flow/pull/3857) - removed the obsolete
"runahead" task state (not used since spawn-on-demand implementation).

[#3816](https://github.com/cylc/cylc-flow/pull/3816) - change `cylc spawn`
command name to `cylc set-outputs` to better reflect its role in Cylc 8.

[#3796](https://github.com/cylc/cylc-flow/pull/3796) - Remote installation is
now on a per install target rather than a per platform basis. `app/`, `bin/`,
`etc/`, `lib/` directories are now installed on the target, configurable in flow.cylc.

[#3724](https://github.com/cylc/cylc-flow/pull/3724) - Re-implemented
the `cylc scan` command line interface and added a Python API for accessing
workflow scanning functionality.

[#3515](https://github.com/cylc/cylc-flow/pull/3515) - spawn-on-demand: a more
efficient way of the evolving the workflow via the graph.

[#3692](https://github.com/cylc/cylc-flow/pull/3692) - Use the `$EDITOR`
and `$GEDITOR` environment variables to determine the default editor to use.

[#3574](https://github.com/cylc/cylc-flow/pull/3574) - use the bash
installation defined in $path rather than hardcoding to /bin/bash.

[#3774](https://github.com/cylc/cylc-flow/pull/3774) - Removed support for
interactive prompt.

[#3798](https://github.com/cylc/cylc-flow/pull/3798) - Deprecated the
`[runtime][X][parameter environment templates]` section and instead allow
templates in `[runtime][X][environment]`.

[#3802](https://github.com/cylc/cylc-flow/pull/3802) - New global config
hierarchy and ability to set site config directory.

[#3848](https://github.com/cylc/cylc-flow/pull/3848) - Deprecated
`[scheduling]max active cycle points` in favour of `[scheduling]runahead limit`.

[#3883](https://github.com/cylc/cylc-flow/pull/3883) - Added a new workflow
config option `[scheduling]stop after cycle point`.

[#3913](https://github.com/cylc/cylc-flow/pull/3913) - Added the ability to
use plugins to parse suite templating variables and additional files to
install. Only one such plugin exists at the time of writing, designed to
parse ``rose-suite.conf`` files in repository "cylc-rose".

[#3955](https://github.com/cylc/cylc-flow/pull/3955) - Global config options
to control the job submission environment.

[#4020](https://github.com/cylc/cylc-flow/pull/4020) - `cylc validate` will no
longer check for a cyclic/circular graph if there are more than 100 tasks,
unless the option  `--check-circular` is used. This is to improve performance.

[#3913](https://github.com/cylc/cylc-flow/pull/3913) - Add ability to use
pre-install entry point from cylc-rose plugin to provide environment and
template variables for a workflow.

[#4023](https://github.com/cylc/cylc-flow/pull/4023) - Add ability to use
post-install entry point from cylc-rose to use Rose style CLI settings of
configurations in Cylc install. If Cylc-rose is installed three new CLI
options will be available:
- `--opt_conf_keys="foo, bar"`
- `--defines="[env]FOO=BAR"`
- `--suite-defines="FOO=BAR"`

[#4101](https://github.com/cylc/cylc-flow/pull/4101) - Add the ability to
ignore (clear) rose install options from an earlier install:
`cylc reinstall --clear-rose-install-options`

[#4094](https://github.com/cylc/cylc-flow/pull/4094) - Prevent Cylc from
rsyncing the following files on install and reinstall:
- `rose-suite.conf`
- `opt/rose-suite-cylc-install.conf`
These files should be handled by the cylc-rose plugin if you require them.

[#4126](https://github.com/cylc/cylc-flow/pull/4126) - Make obselete the config
``flow.cylc:[runtime][__TASK__][remote]suite definition directory``.

[#4098](https://github.com/cylc/cylc-flow/pull/4098) - Provide a dictionary called
CYLC_TEMPLATE_VARS into the templating environment.

[#4099](https://github.com/cylc/cylc-flow/pull/4099) - Unify `cylc get-suite-config`
and `cylc get-site-config` commands as `cylc config`. Some options have been
removed.

### Fixes

[#3984](https://github.com/cylc/cylc-flow/pull/3984) - Only write task
event timers to the database when they have changed (reverts behaviour
change in 7.8.6). This corrects last updated db entries and reduces filesystem
load.

[#3917](https://github.com/cylc/cylc-flow/pull/3917) - Fix a bug that caused
one of the hostname resolution tests to fail in certain environments.

[#3879](https://github.com/cylc/cylc-flow/pull/3879) - Removed Google
Groups e-mail from pip packaging metadata. Users browsing PYPI will have
to visit our website to find out how to reach us (we are using Discourse
and it does not offer an e-mail address).

[#3859](https://github.com/cylc/cylc-flow/pull/3859) - Fixes the query of
broadcast states to retrieve only the data for the requested ID, instead
of returning all the broadcast states in the database.

[#3815](https://github.com/cylc/cylc-flow/pull/3815) - Fixes a minor bug in the
auto-restart functionality which caused suites to wait for local jobs running
on *any* host to complete before restarting.

[#3732](https://github.com/cylc/cylc-flow/pull/3732) - XTrigger labels
are now validated to ensure that runtime errors can not occur when
exporting environment variables.

[#3632](https://github.com/cylc/cylc-flow/pull/3632) - Fix a bug that was causing
`UTC mode` specified in global config to be pretty much ignored.

[#3614](https://github.com/cylc/cylc-flow/pull/3614) - Ensure the suite always
restarts using the same time zone as the last `cylc run`.

[#3788](https://github.com/cylc/cylc-flow/pull/3788),
[#3820](https://github.com/cylc/cylc-flow/pull/3820) - Task messages and
task outputs/message triggers are now validated.

[#3614](https://github.com/cylc/cylc-flow/pull/3795) - Fix error when running
`cylc ping --verbose $SUITE`.

[#3852](https://github.com/cylc/cylc-flow/pull/3852) - Prevents registering a
workflow in a sub-directory of a run directory (as `cylc scan` would not be
able to find it).

[#3452](https://github.com/cylc/cylc-flow/pull/3452) - Fix param graph
issue when mixing offset and conditional (e.g. foo<m-1> & baz => foo<m>).

[#3982](https://github.com/cylc/cylc-flow/pull/3982) - Fix bug preventing
workflow from shutting down properly on a keyboard interrupt (Ctrl+C) in
Python 3.8+.

[#4011](https://github.com/cylc/cylc-flow/pull/4011) - Fix bug where including
a trailing slash in the suite/workflow name would cause `cylc stop`
(and possibly other commands) to silently fail.

[#4046](https://github.com/cylc/cylc-flow/pull/4046) - Fix bug where a workflow
database could still be active for a short time after the workflow stops.

-------------------------------------------------------------------------------
## __cylc-8.0a2 (2020-07-03)__

Third alpha release of Cylc 8.

(See note on cylc-8 backward-incompatible changes, above)

The commands `cylc submit` and `cylc jobscript` have been removed.

### Enhancements

[#3389](https://github.com/cylc/cylc-flow/pull/3389) - Publisher/Subscriber
network components added (0MQ PUB/SUB pattern). Used to publish fine-grained
data-store updates for the purposes of UI Server data sync, this change also
includes CLI utility: `cylc subscribe`.

[#3402](https://github.com/cylc/cylc-flow/pull/3402) - removed automatic task
job status message retries (problems that prevent message transmission are
almost never transient, and in practice job polling is the only way to
recover).

[#3463](https://github.com/cylc/cylc-flow/pull/3463) - cylc tui:
A new terminal user interface to replace the old `cylc monitor`.
An interactive collapsible tree to match the new web interface.

[#3559](https://github.com/cylc/cylc-flow/pull/3559) - Cylc configuration
files are now auto-documented from their definitions.

[#3617](https://github.com/cylc/cylc-flow/pull/3617) - For integer cycling mode
there is now a default initial cycle point of 1.

[#3423](https://github.com/cylc/cylc-flow/pull/3423) - automatic task retries
re-implemented using xtriggers. Retrying tasks will now be in the "waiting"
state with a wall_clock xtrigger set for the retry time.

### Fixes

[#3618](https://github.com/cylc/cylc-flow/pull/3618) - Clear queue configuration
warnings for referencing undefined or unused tasks.

[#3596](https://github.com/cylc/cylc-flow/pull/3596) - Fix a bug that could
prevent housekeeping of the task_action_timers DB table and cause many warnings
at restart.

[#3602](https://github.com/cylc/cylc-flow/pull/3602) - Fix a bug that prevented
cycle point format conversion by the `cylc suite-state` command and the
`suite_state` xtrigger function, if the target suite used the default format
but downstream command or suite did not.

[#3541](https://github.com/cylc/cylc-flow/pull/3541) - Don't warn that a task
was already added to an internal queue, if the queue is the same.

[#3409](https://github.com/cylc/cylc-flow/pull/3409) - prevent cylc-run from
creating directories when executed for suites that do not exist.

[#3433](https://github.com/cylc/cylc-flow/pull/3433) - fix server abort at
shutdown during remote run dir tidy (introduced during Cylc 8 development).

[#3493](https://github.com/cylc/cylc-flow/pull/3493) - Update jinja2 and
pyzmq, as well as some test/dev dependencies. Fixes Jinja2 error where
validation shows incorrect context.

[#3531](https://github.com/cylc/cylc-flow/pull/3531) - Fix job submission to
SLURM when task name has a percent `%` character.

[#3543](https://github.com/cylc/cylc-flow/pull/3543) - fixed pipe polling
issue observed on darwin (BSD) which could cause Cylc to hang.

-------------------------------------------------------------------------------
## __cylc-8.0a1 (2019-09-18)__

Second alpha release of Cylc 8.

(See note on cylc-8 backward-incompatible changes, above)

### Enhancements

[#3377](https://github.com/cylc/cylc-flow/pull/3377) - removed support for
sourcing `job-init-env.sh` in task job scripts. Use bash login scripts instead.

[#3302](https://github.com/cylc/cylc-flow/pull/3302) - improve CLI
task-globbing help.

[#2935](https://github.com/cylc/cylc-flow/pull/2935) - support alternate run
directories, particularly for sub-suites.

[#3096](https://github.com/cylc/cylc-flow/pull/3096) - add colour to the
Cylc CLI.

[#2963](https://github.com/cylc/cylc-flow/pull/2963) - make suite context
available before config parsing.

[#3274](https://github.com/cylc/cylc-flow/pull/3274) - disallow the use of
special characters in suite names.

[#3001](https://github.com/cylc/cylc-flow/pull/3001) - simplify cylc version,
dropping VERSION file and git info.

[#3007](https://github.com/cylc/cylc-flow/pull/3007) - add tests for quoting
of tilde expressions in environment section.

[#3006](https://github.com/cylc/cylc-flow/pull/3006) - remove cylc.profiling
package and cylc-profile-battery.

[#2998](https://github.com/cylc/cylc-flow/pull/2998) - Bandit security
recommendations for Cylc 8 target.

[#3024](https://github.com/cylc/cylc-flow/pull/3024) - remove remaining Cylc
Review files.

[#3022](https://github.com/cylc/cylc-flow/pull/3022) - removed LaTeX support
from check-software.

[#3029](https://github.com/cylc/cylc-flow/pull/3029) - remove dev-suites
from tests.

[#3036](https://github.com/cylc/cylc-flow/pull/3036) - re-enable EmPy
templating.

[#3044](https://github.com/cylc/cylc-flow/pull/3044) - remove GTK labels
from task states.

[#3055](https://github.com/cylc/cylc-flow/pull/3055) - simplify regexes.

[#2995](https://github.com/cylc/cylc-flow/pull/2995) - elegantly handle
known errors.

[#3069](https://github.com/cylc/cylc-flow/pull/3069) - make Python 3.7 the
min version for Cylc.

[#3068](https://github.com/cylc/cylc-flow/pull/3068) - add shellcheck to
lint shell script files.

[#3088](https://github.com/cylc/cylc-flow/pull/3088) - remove obsolete
ksh support.

[#3091](https://github.com/cylc/cylc-flow/pull/3091) - remove useless
license commands.

[#3095](https://github.com/cylc/cylc-flow/pull/3095) - run prove with
--timer.

[#3093](https://github.com/cylc/cylc-flow/pull/3093) - job.sh: run
as bash only.

[#3101](https://github.com/cylc/cylc-flow/pull/3101) - add kill all to
functional tests.

[#3123](https://github.com/cylc/cylc-flow/pull/3123) - remove Kafka
xtrigger example.

[#2990](https://github.com/cylc/cylc-flow/pull/2990) - make cylc a module.

[#3131](https://github.com/cylc/cylc-flow/pull/3131) - renamed cylc to
cylc-flow, and simplified project summary.

[#3140](https://github.com/cylc/cylc-flow/pull/3140) - cylc-flow rename in
README badges, setup.py, and a few more places.

[#3138](https://github.com/cylc/cylc-flow/pull/3138) - add suite aborted
event.

[#3132](https://github.com/cylc/cylc-flow/pull/3132) - move parsec to
cylc.parsec.

[#3113](https://github.com/cylc/cylc-flow/pull/3113) - document
select_autoescape security ignore.

[#3083](https://github.com/cylc/cylc-flow/pull/3083) - extend
ZMQClient and update docstrings.

[#3155](https://github.com/cylc/cylc-flow/pull/3155) - remove changed
variable in async_map.

[#3135](https://github.com/cylc/cylc-flow/pull/3135) - incorporate
jinja2filters into cylc.flow.jinja.filters, and use native namespaces.

[#3134](https://github.com/cylc/cylc-flow/pull/3134) - update how
CYLC_DIR is used in Cylc.

[#3165](https://github.com/cylc/cylc-flow/pull/3165) - added GitHub
Issue and Pull Request templates.

[#3272](https://github.com/cylc/cylc-flow/pull/3272),
[#3191](https://github.com/cylc/cylc-flow/pull/3191) - uniform configuration
section level for defining non-cycling and cycling graphs. E.g.:

```
# Deprecated Syntax
[scheduling]
    initial cycle point = next(T00)
    [[dependencies]]
        [[[P1D]]]
            graph = task1 => task2
```

Can now be written as:

```
# New Syntax
[scheduling]
    initial cycle point = next(T00)
    [[graph]]
        P1D = task1 => task2
```

[#3249](https://github.com/cylc/cylc-flow/pull/3249) - export the environment
variable `ISODATETIMEREF` (reference time for the `isodatetime` command from
[metomi-isodatetime](https://github.com/metomi/isodatetime/)) in task jobs to
have the same value as `CYLC_TASK_CYCLE_POINT`.

[#3286](https://github.com/cylc/cylc-flow/pull/3286) -
Removed the `cylc check-triggering` command.
Changed the `suite.rc` schema:
* Removed `[cylc]log resolved dependencies`
* Removed `[cylc][[reference test]]*` except `expected task failures`.
* Moved `[cylc]abort if any task fails` to
  `[cylc][[events]]abort if any task fails` so it lives with the other
  `abort if/on ...` settings.

[#3351](https://github.com/cylc/cylc-flow/pull/3351) - sped up suite validation
(which also affects responsiveness of suite controllers during suite startup,
restarts, and reloads).  Impact of the speedup is most noticeable when dealing
with suite configurations that contain tasks with many task outputs.

[#3358](https://github.com/cylc/cylc-flow/pull/3358) - on submitting jobs to
SLURM or LSF, the job names will now follow the pattern `task.cycle.suite`
(instead of `suite.task.cycle`), for consistency with jobs on PBS.

[#3356](https://github.com/cylc/cylc-flow/pull/3356) - default job name length
maximum for PBS is now 236 characters (i.e. assuming PBS 13 or newer). If you
are still using PBS 12 or older, you should add a site configuration to
restrict it to 15 characters.

### Fixes

[#3308](https://github.com/cylc/cylc-flow/pull/3308) - fix a long-standing bug
causing suites to stall some time after reloading a suite definition that
removed tasks from the graph.

[#3287](https://github.com/cylc/cylc-flow/pull/3287) - fix xtrigger
cycle-sequence specificity.

[#3258](https://github.com/cylc/cylc-flow/pull/3258) - leave '%'-escaped string
templates alone in xtrigger arguments.

[#3010](https://github.com/cylc/cylc-flow/pull/3010) - fixes except KeyError
in task_job_mgr.

[#3031](https://github.com/cylc/cylc-flow/pull/3031) - convert range to list
so that we can use reduce.

[#3040](https://github.com/cylc/cylc-flow/pull/3040) - add check for zero
to xrandom.

[#3018](https://github.com/cylc/cylc-flow/pull/3018) - subprocpool: use
SpooledTemporaryFile instead of TemporaryFile.

[#3032](https://github.com/cylc/cylc-flow/pull/3032) - fix syntax for
array access in cylc check-software.

[#3035](https://github.com/cylc/cylc-flow/pull/3035) - fix scheduler#shutdown
when reference-log option is used.

[#3056](https://github.com/cylc/cylc-flow/pull/3056) - fix suite freeze on
non-existent xtrigger.

[#3060](https://github.com/cylc/cylc-flow/pull/3060) - fix bug when an
AttributeError is raised, and add unit tests for xtrigger.

[#3015](https://github.com/cylc/cylc-flow/pull/3015) - use global client
zmq context.

[#3092](https://github.com/cylc/cylc-flow/pull/3092) - fix recent
shellcheck-inspired quoting errors.

[#3085](https://github.com/cylc/cylc-flow/pull/3085) - fix cylc-search
for directories without suite.rc.

[#3105](https://github.com/cylc/cylc-flow/pull/3105) - fix work location
assumption in a test.

[#3112](https://github.com/cylc/cylc-flow/pull/3112) - prepend custom
Jinja2 paths.

[#3130](https://github.com/cylc/cylc-flow/pull/3130) - remove Python 2
compatibility in setup.py for wheel.

[#3137](https://github.com/cylc/cylc-flow/pull/3137) - fix job kill
hold-retry logic.

[#3077](https://github.com/cylc/cylc-flow/pull/3077) - support single
port configuration for zmq.

[#3153](https://github.com/cylc/cylc-flow/pull/3153) - fix bug in
async_map.

[#3164](https://github.com/cylc/cylc-flow/pull/3164) - fix pclient
undefined error.

[#3173](https://github.com/cylc/cylc-flow/issues/3173) - NameError when
invalid cylc command is used (instead of a ValueError).

[#3003](https://github.com/cylc/cylc-flow/pull/3003) - Fix inheritance
with quotes using shlex.

[#3184](https://github.com/cylc/cylc-flow/pull/3184) - Fix restart
correctness when the suite has a hold point, stop point, a stop task, a stop
clock time and/or an auto stop option. These settings are now stored in the
suite run SQLite file and are retrieved on suite restart. In addition, the
settings are removed when they are consumed, e.g. if the suite stopped
previously on reaching the stop point, the stop point would be consumed, so
that on restart the suite would not stop again immediately.

The `cylc run` command can now accept `--initial-cycle-point=CYCLE-POINT`
(`--icp=CYCLE-POINT)` and `--start-cycle-point=CYCLE-POINT` options. This
change should allow the command to have  a more uniform interface with commands
such as `cylc validate`, and with the final/stop cycle point options).

After this change:
* `cylc run SUITE POINT` is equivalent to `cylc run --icp=POINT SUITE`.
* `cylc run -w SUITE POINT` is equivalent to
  `cylc run -w --start-point=POINT SUITE`.

The `cylc run` and `cylc restart` commands can now accept the
`--final-cycle-point=POINT` and `--stop-cycle-point=POINT` options. The
`--until=POINT` option is now an alias for `--final-cycle-point=POINT` option.

The `cylc run` and `cylc restart` commands can now accept the new
`--auto-shutdown` option. This option overrides the equivalent suite
configuration to force auto shutdown to be enabled. Previously, it is only
possible to disable auto shutdown on the command line.

[#3236](https://github.com/cylc/cylc-flow/pull/3236) - Fix submit number
increment logic on insert of family with tasks that were previously submitted.

[#3276](https://github.com/cylc/cylc-flow/pull/3276) - Fix log & DB recording
of broadcasts from xtriggers so they register all settings, not just one.

[#3325](https://github.com/cylc/cylc-flow/pull/3325) - Fix task event handler
*start_time* being unavailable in *started* events.

### Documentation

[#3181](https://github.com/cylc/cylc-flow/pull/3181) - moved documentation to
the new cylc/cylc-doc repository.

[#3025](https://github.com/cylc/cylc-flow/pull/3025) - fix dev-suites
reference in docs (now in examples).

[#3004](https://github.com/cylc/cylc-flow/pull/3004) - document suite
runtime interface.

[#3066](https://github.com/cylc/cylc-flow/pull/3066) - minor fix to
docs about exit-script.

[#3108](https://github.com/cylc/cylc-flow/pull/3108) - anatomy of a
job script.

[#3129](https://github.com/cylc/cylc-flow/pull/3129) - added
SECURITY.md.

[#3151](https://github.com/cylc/cylc-flow/pull/3151) - fix documentation
heading levels.

[#3158](https://github.com/cylc/cylc-flow/pull/3158) - fix \ in doco
when wrapped in ``..``.

### Security issues

None. Note that we added a `SECURITY.md` file in this release (see #3129)
with instructions for reporting security issues, as well as a
listing with current incident reports.

-------------------------------------------------------------------------------
## __cylc-8.0a0 (2019-03-12)__

First alpha release of Cylc 8. Also first release of Cylc uploaded
to PYPI: https://pypi.org/project/cylc-flow/.

(See note on cylc-8 backward-incompatible changes, above)

### Enhancements

[#2936](https://github.com/cylc/cylc-flow/pull/2936) - remove obsolete commands,
modules, configuration, and documentation.

[#2966](https://github.com/cylc/cylc-flow/pull/2966) - port Cylc to Python 3.

### Fixes

None.

### Documentation

[#2939](https://github.com/cylc/cylc-flow/pull/2939) - use higher contrast link
colours for the generated documentation.

[#2954](https://github.com/cylc/cylc-flow/pull/2954) - fix jinja2 variable
setting example suites.

[#2951](https://github.com/cylc/cylc-flow/pull/2951) - amend makefile command
and address warning.

[#2971](https://github.com/cylc/cylc-flow/pull/2971) - general single- and
multi-page User Guides.

### Security issues

None.

-------------------------------------------------------------------------------
## __cylc-7.8.1 (2019-01-25)__

Maintenance and minor enhancement release, plus new-format User Guide.

Selected user-facing changes:

### Enhancements

[#2910](https://github.com/cylc/cylc-flow/pull/2910) - replace LaTeX-generated HTML
and PDF User Guide with Sphinx-generated HTML.

[#2815](https://github.com/cylc/cylc-flow/pull/2815) - allow initial cycle point
relative to current time.

[#2902](https://github.com/cylc/cylc-flow/pull/2902) - expose suite UUID to event
handlers.

### Fixes

[#2932](https://github.com/cylc/cylc-flow/pull/2932) - fix possible blocking pipe
due to chatty job submission (and other subprocess) commands.

[#2921](https://github.com/cylc/cylc-flow/pull/2921) - better suite validation
warning for out-of-bounds cycling sequences.

[#2924](https://github.com/cylc/cylc-flow/pull/2924) - fix and expand 7.8.0 `cylc
review` documentation in the User Guide.

-------------------------------------------------------------------------------
## __cylc-7.8.0 (2018-11-27)__

Minor release with over 120 issues closed. Significant issues include:

### Enhancements

[#2693](https://github.com/cylc/cylc-flow/pull/2693) - __auto host selection__; and
[#2809](https://github.com/cylc/cylc-flow/pull/2809) - __auto migration__.
`cylc run` and `cylc restart` can now select the best host (based on several
metrics) on which to launch suite server programs. And running suites
can be told (via global config) to self-migrate to another available host, e.g.
for server maintenance. (The pool of suite hosts should see a shared
filesystem).

[#2614](https://github.com/cylc/cylc-flow/pull/2614) and
[#2821](https://github.com/cylc/cylc-flow/pull/2821) - __web-based job log viewer__ -
 `cylc review` (migration of "Rose Bush" from the Rose project).


[#2339](https://github.com/cylc/cylc-flow/pull/2339) - __general external
triggering__: tasks can trigger off of arbitrary user-defined Python functions
called periodically by the suite server program, with built-in functions
for suite-state (inter-suite) triggering and clock triggering (these
deprecate the existing suite-state polling tasks and clock-triggered tasks).

[#2734](https://github.com/cylc/cylc-flow/pull/2734) - __EmPy templating__
support, as an alternative to Jinja2. _"EmPy allows embedding plain Python code
within templates and doesn't enforce any particular templating philosophy."_

[#2733](https://github.com/cylc/cylc-flow/pull/2733) - enhanced Jinja2 support:
- __import pure Python modules__ in the same way as template modules
- Jinja2Tests and Jinja2Globals, for custom "is" tests and global variables
  (c.f. our existing Jinja2Filters for custom filters).

[#2682](https://github.com/cylc/cylc-flow/pull/2682) - new built-in
Jinja2 filter to convert ISO8601 date-time durations to
decimal seconds or hours.

[#2842](https://github.com/cylc/cylc-flow/pull/2842) - `cylc gui` and
`cylc graph` - better integration with system desktop themes, including dark
themes; and other minor graph visualization improvements.

[#2807](https://github.com/cylc/cylc-flow/pull/2807) - task output events (event
handlers can now be triggered when a task reports a registered output message).

[#2868](https://github.com/cylc/cylc-flow/pull/2868) - a new task
runtime config item `exit-script`, for scripting to be executed at the
last moment after successful job completion. (Companion of `err-script`).

[#2781](https://github.com/cylc/cylc-flow/pull/2781) and
[#2854](https://github.com/cylc/cylc-flow/pull/2854) - improved suite
server program logging (including: `log/suite/err` is no longer used).

[#2849](https://github.com/cylc/cylc-flow/pull/2849) - record local
background jobs by host name rather than "localhost".

[#2877](https://github.com/cylc/cylc-flow/pull/2877) - new batch system
handler `pbs_multi_cluster`, supports PBS 13 clients fronting
heterogeneous clusters with different home directories from the
cylc remote. (Not needed for PBS 14+.) (For Rose suites this requires a
corresponding change to `rose suite-run`:
[metomi/rose#2252](https://github.com/metomi/rose/pull/2252).)

[#2812](https://github.com/cylc/cylc-flow/pull/2812) - `cylc gscan`:
show application menu bar by default.

[#2768](https://github.com/cylc/cylc-flow/pull/2768) - `cylc gscan`: display Cylc
version of running suites.

[#2786](https://github.com/cylc/cylc-flow/pull/2786) - make task try number
available to event handlers (as for task job submit number).

[#2771](https://github.com/cylc/cylc-flow/pull/2771) - bash command completion:
complete suite names for commands that take a suite name argument (see
`etc/cylc-bash-completion`).

[#2769](https://github.com/cylc/cylc-flow/pull/2769) - `cylc check-software` now
takes arguments to check for availability of specific modules.

[#2763](https://github.com/cylc/cylc-flow/pull/2763) - `cylc monitor` - clean exit
on Ctrl-C.

[#2704](https://github.com/cylc/cylc-flow/pull/2704) - paginated `cylc help` output.

[#2660](https://github.com/cylc/cylc-flow/pull/2660) - new `gcylc.rc` config item to
show grouped cyclepoint subgraphs by default.

[#2766](https://github.com/cylc/cylc-flow/pull/2766) - (development) formal test
coverage reporting and integration with GitHub.

[#2751](https://github.com/cylc/cylc-flow/pull/2751) - (development) new contributor
guidelines - see `CONTRIBUTING.md`.

### Fixes

[#2876](https://github.com/cylc/cylc-flow/pull/2876) - avoid subprocess hang when
executing commands that generate a lot of stdout (such as when submitting
hundreds of jobs at once).

[#2828](https://github.com/cylc/cylc-flow/pull/2828) - `suite.rc` - fail validation
on detecting trailing whitespace after a line continuation character.

[#2807](https://github.com/cylc/cylc-flow/pull/2807) - handle multiple events of
the same type with the same message (e.g. warnings) from the same task job.

[#2803](https://github.com/cylc/cylc-flow/pull/2803) - reset job submit number
correctly after aborting (backing out of) a trigger edit-run.

[#2727](https://github.com/cylc/cylc-flow/pull/2727) - `cylc gui`: fix dropdown list
of log numbers for re-inserted tasks or after suite
restart.

[#2759](https://github.com/cylc/cylc-flow/pull/2759) and
[#2816](https://github.com/cylc/cylc-flow/pull/2816) -
suite registration tweaks and fixes.

[#2861](https://github.com/cylc/cylc-flow/pull/2861) - improved emacs
syntax highlighting.

[#2892](https://github.com/cylc/cylc-flow/pull/2892) - print the bad host name along
with "Name or service not known" exceptions.


-------------------------------------------------------------------------------
## __cylc-7.7.2 (2018-07-26)__

Maintenance release.

(Some minor changes not relevant to normal users may be omitted.)

### Fixes and minor enhancements

[#2719](https://github.com/cylc/cylc-flow/pull/2719) - improved job poll logging

[#2724](https://github.com/cylc/cylc-flow/pull/2724) - fix a rare error associated
with ithe use of final cycle point in multiple recurrence expressions

[#2723](https://github.com/cylc/cylc-flow/pull/2723) - fix remote commands (executed
by remote task jobs) running in UTC mode when the suite is not running in UTC
mode

[#2726](https://github.com/cylc/cylc-flow/pull/2726) - fix crash in suites with no
final cycle point that are reloaded following a restart

[#2716](https://github.com/cylc/cylc-flow/pull/2716) - ensure that job polling
interval lists are not overridden

[#2714](https://github.com/cylc/cylc-flow/pull/2714) - block irrelevant
`InsecureRequestWarning`s from urllib3 on anonymous suite server access by
`cylc scan` and `cylc ping`

[#2715](https://github.com/cylc/cylc-flow/pull/2715) - fix a cross-version
incompatibility, if a cylc-7.6.x task job messages a cylc-7.7.1 suite

[#2710](https://github.com/cylc/cylc-flow/pull/2710) - fix a GUI error on
right-clicking a "scissor node" in the graph view

-------------------------------------------------------------------------------
## __cylc-7.7.1 (2018-06-27)__

Minor maintenance release.

### Fixes

(Several minor fixes have been omitted from this list.)

[#2678](https://github.com/cylc/cylc-flow/pull/2678) - fix loading of job poll
timers on restart (bug introduced at last release)

[#2683](https://github.com/cylc/cylc-flow/pull/2683) - fix potential error in
`cylc check-software` (which checks for installed software dependencies)

[#2691](https://github.com/cylc/cylc-flow/pull/2691) PBS support - handle job poll
result correctly if qstat temporarily fails to connect to the server

[#2703](https://github.com/cylc/cylc-flow/pull/2703) - fix an error
(inconsequential) that appears in the suite log at restart: `ValueError: No
JSON object could be decoded`

[#2692](https://github.com/cylc/cylc-flow/pull/2692) - fix X11 forwarding for GUI
edit job log, with `cylc gui --host=HOST`

[#2690](https://github.com/cylc/cylc-flow/pull/2690) - invoking Cylc command help
should not require `$DISPLAY` to be set

[#2677](https://github.com/cylc/cylc-flow/pull/2677) - use random serial numbers in
the self-signed SSL certificates generated by suite server programs

[#2688](https://github.com/cylc/cylc-flow/pull/2688)
[#2705](https://github.com/cylc/cylc-flow/pull/2705) - block several security
warnings emitted by `urllib3` under old Python versions (2.6). *We are
aware of the security issues, but these warnings serve no purpose on affected
platforms except to confuse and annoy users.*

[#2676](https://github.com/cylc/cylc-flow/pull/2676) - use `#!/usr/bin/env python2`
(i.e. Python-2 specific) in Cylc source files, to avoid issues with default
Python 3 installations (note Cylc is going to Python 3 next year)

[#2679](https://github.com/cylc/cylc-flow/pull/2679) - change bold font back to
normal in the GUI log viewer

-------------------------------------------------------------------------------
## __cylc-7.7.0 (2018-05-12)__

### Enhancements

[#2661](https://github.com/cylc/cylc-flow/pull/2661) -
 * new User Guide section on Remote Job Management
 * tidy the installation documentation
 * standardise directory structures (all docs updated accordingly):
   - deprecated `<cylc-dir>conf/` file locations:
     - site config file `<cylc-dir>etc/global.rc`
     - gcylc config example `<cylc-dir>/etc/gcylc.rc.eg`
     - site job environment init `<cylc-dir/etc/job-init-env.sh`
     - editor syntax files in `<cylc-dir>etc/syntax/`
     - bash completion script `<cylc-dir>/etc/cylc-bash-completion`
   - user `global.rc` can now go in `~/.cylc/<cylc-version>/` or `~/.cylc/`
     (the version-specific location avoid forward compatibility problems - see
     notes in `<cylc-dir>/etc/global.rc.eg`).
   - moved central cylc wrapper template to `usr/bin/cylc`
   - various developer scripts and notes moved from `<cylc-dir>/dev/` to
     `<cylc-dir>/etc/dev-bin, dev-notes, dev-suites`.
   - *the ancient `site.rc` and `user.rc` global config filename variants are
     now obsolete.*

[#2659](https://github.com/cylc/cylc-flow/pull/2659) - commands in the process pool
(event handlers, and job submit, poll and kill commands) will now be killed on
a configurable timeout if they hang, rather than tying up a member of the
finite process pool: `global.rc` default: `process pool timeout = PT10M`

[#2582](https://github.com/cylc/cylc-flow/pull/2582) - improve client/server
interface, including: `cylc message` can send multiple messages at once, with
different severities; server ignores messages from superseded job submits;
running jobs detect that the suite has been cold-started under them and will
not attempt to connect; ssh-based indirect client-server communication now
works automatically for all clients, not just messaging.

[#2582](https://github.com/cylc/cylc-flow/pull/2582),
[#2624](https://github.com/cylc/cylc-flow/pull/2624), and earlier changes: all job
host actions are now done by remote `cylc` subcommands that are compatible with
ssh whitelisting.

[#2590](https://github.com/cylc/cylc-flow/pull/2590) - replaced the fixed process
pool with direct management of individual sub-processes (for external commands
executed by the server program).

[#2561](https://github.com/cylc/cylc-flow/pull/2561) - pass resolved triggering
dependencies to `$CYLC_TASK_DEPENDENCIES` in job environments.

[#2639](https://github.com/cylc/cylc-flow/pull/2639) - date-time cycling: document
availability of 365-day (never a leap year) and 366-day (always a leap year)
calendars.

[#2597](https://github.com/cylc/cylc-flow/pull/2597) - emit a "late" event if a task
has not triggered by a user-defined real-time offset relative to cycle point.

[#2648](https://github.com/cylc/cylc-flow/pull/2648) - improve version reporting.
Note than non-standard lowercase `cylc -v` is now gone; use `cylc -V` or `cylc
--version`, with optional `--long` format to print as well as version.

[#2620](https://github.com/cylc/cylc-flow/pull/2620) - re-document the long-dated
`[special tasks]sequential` and recommend using explicit dependencies in the
graph instead.

[#2584](https://github.com/cylc/cylc-flow/pull/2584) - internal queues now release
task jobs on a FIFO (First In, First Out) basis, rather than randomly.

[#2538](https://github.com/cylc/cylc-flow/pull/2538) - remove leading whitespace
from multi-line `script` items in task definitions, for cleaner job scripts.

[#2503](https://github.com/cylc/cylc-flow/pull/2503),
[#2624](https://github.com/cylc/cylc-flow/pull/2624) - `cylc cat-log`: all remote
host actions now done by a `cylc` sub-command; and simpler command options (see
`cylc cat-log --help`; **warning: the old command options are not supported**)

### Fixes

[#2666](https://github.com/cylc/cylc-flow/pull/2666) - `cylc scan`: make default
behavior consistent with `cylc gscan`: get suite information from `~/cylc-run/`
only for the current user; and no partial matches with `-n/--name=PATTERN`
(i.e. `--name=bar` will only match the suite `bar`, not `foobar` or `barbaz`).

[#2593](https://github.com/cylc/cylc-flow/pull/2593) - fix polling after job
execution timeout (configured pre-poll delays were being ignored).

[#2656](https://github.com/cylc/cylc-flow/pull/2656) - fix suicide triggers with
multiple prerequisites in the same graph line.

[#2638](https://github.com/cylc/cylc-flow/pull/2638) - fix duplicate "failed" task
events after `cylc stop --kill`.

[#2653](https://github.com/cylc/cylc-flow/pull/2653) - tidy and correct the main `cylc
help` documentation.

[#2644](https://github.com/cylc/cylc-flow/pull/2644),
[#2646](https://github.com/cylc/cylc-flow/pull/2646) - fix some graph parsing edge
cases.

[#2649](https://github.com/cylc/cylc-flow/pull/2649) - respect suite
UTC mode when recording job submit time (database and GUI tree view).

[#2631](https://github.com/cylc/cylc-flow/pull/2631) - fix "failed" task event after
bad host select.

[#2626](https://github.com/cylc/cylc-flow/pull/2626) - `cylc gui`: fix error when
a task job completes just before "view task prerequisites" (menu) is actioned.

[#2600](https://github.com/cylc/cylc-flow/pull/2600) - correct task prerequisite
manipulation on state changes.

[#2596](https://github.com/cylc/cylc-flow/pull/2596) - fix reference to parameter
values containing `+` or `-` characters.

[#2592](https://github.com/cylc/cylc-flow/pull/2592) - permit syntax errors in edit
runs, so that the job file still gets written.

[#2579](https://github.com/cylc/cylc-flow/pull/2579) - `cylc gscan`: fix a
re-spawning error dialog.

[#2674](https://github.com/cylc/cylc-flow/pull/2674) - `cylc cat-log`: avoid leaving
orphaned tail-follow processes on job hosts.


-------------------------------------------------------------------------------
## __cylc-7.6.1 (2018-03-28)__

A collection of bug fixes made since cylc-7.6.0.

### Fixes

[#2571](https://github.com/cylc/cylc-flow/pull/2571) - `cylc gui`: fix tailing of
remote job logs from the GUI (in 7.6.0 this failed with a Python traceback).

[#2596](https://github.com/cylc/cylc-flow/pull/2596) - allow parameter values that
contain +/- characters

[#2574](https://github.com/cylc/cylc-flow/pull/2574) - `cylc gscan HOST`: show just
the owner's suites by default (at 7.6.0 this showed all suites on HOST).

[#2592](https://github.com/cylc/cylc-flow/pull/2592) - `cylc trigger --edit`:
disable job script syntax checking in edit runs (this prevented a new job
script from being written for editing).

[#2579](https://github.com/cylc/cylc-flow/pull/2579) - `cylc gscan`: fix respawning
error dialog on giving a bad regular expression (on the command line) to match
owner or suite name.

[#2606](https://github.com/cylc/cylc-flow/pull/2606) - jobs with batch system info
missing in a corrupted status file (thus not pollable) will now poll as failed
rather appear stuck as running.

[#2603](https://github.com/cylc/cylc-flow/pull/2603) - `cylc gui` (graph view): fix
possible error on inserting a nested family.

[#2602](https://github.com/cylc/cylc-flow/pull/2602) - `cylc gui` (tree view): fix
negative progress bar value (reportedly possible after manual task state
manipulations).

[#2586](https://github.com/cylc/cylc-flow/pull/2586) - `cylc gui` (tree view): fix
possible division-by-zero error in elapsed time computation.

[#2588](https://github.com/cylc/cylc-flow/pull/2588) - `cylc trigger --edit`: fix
edit runs for tasks with dynamic remote host selection.

[#2585](https://github.com/cylc/cylc-flow/pull/2585) - fix recovery from a failed
host select command.

-------------------------------------------------------------------------------
## __cylc-7.6.0 (2018-02-07)__

### Enhancements

[#2373](https://github.com/cylc/cylc-flow/pull/2373) - refactored suite server code
(for efficiency, maintainability, etc.)

[#2396](https://github.com/cylc/cylc-flow/pull/2396) - improved job polling and task
state reset:
 * allow polling of finished tasks - to confirm they really succeeded or failed
 * poll to confirm a task message that implies a state reversal - it could just
   be a delayed message
 * allow reset to submitted or running states
 * removed the "enable resurrection" setting - any task can now return from the
   dead

[#2410](https://github.com/cylc/cylc-flow/pull/2410) - new CUSTOM severity task
messages that can trigger a custom event handler

[#2420](https://github.com/cylc/cylc-flow/pull/2420) - `cylc monitor` now
reconnects automatically if its target suite gets restarted on a different port

[#2430](https://github.com/cylc/cylc-flow/pull/2430) - `cylc gscan`,
`cylc gui` - significant reduction in impact on suite server
programs

[#2433](https://github.com/cylc/cylc-flow/pull/2433) - "group" (used to group suites
in `cylc gscan`) is now defined under the suite "[[meta]]" section

[#2424](https://github.com/cylc/cylc-flow/pull/2424) - task job scripts now run in
`bash -l` (login shell) instead of explicitly sourcing your
`.profile` file. *WARNING*: if you have a
`.bash_profile` and were using `.profile` as well just for
Cylc, the latter file will now be ignored because bash gives precedence to the
former. If so, just move your Cylc settings into
`.bash_profile` or consult the Cylc User Guide for
other ways to configure the task job environment.

[#2441](https://github.com/cylc/cylc-flow/pull/2441) -
[#2458](https://github.com/cylc/cylc-flow/pull/2458) - allow more event handler
arguments:
 * batch system name and job ID
 * submit time, start time, finish time
 * user@host

[#2455](https://github.com/cylc/cylc-flow/pull/2455) - network client improvements:
 * on a failed connection, clients detect if the suite has stopped according to
   the contact file, then report it stopped and remove the contact file
 * on attempt run an already-running suite (contact file exists) print more
   information on how old the suite is and how to shut it down
 * clients running in plain HTTP protocol will no longer attempt to fetch a
   non-existent SSL certificate
 * if a contact file is loaded, always use the values in it to avoid
   conflicting host strings in SSL certificate file, etc.

[#2468](https://github.com/cylc/cylc-flow/pull/2468) - initialize task remotes
asynchronously via the multiprocessing pool, to avoid holding up suite start-up
unnecessarily. *WARNING* this introduces new remote commands: `cylc
remote-init` and `cylc remote-tidy` that will affect sites
using ssh whitelisting

[#2449](https://github.com/cylc/cylc-flow/pull/2449) -
[#2469](https://github.com/cylc/cylc-flow/pull/2469) -
[#2480](https://github.com/cylc/cylc-flow/pull/2480) -
[#2501](https://github.com/cylc/cylc-flow/pull/2501) -
[#2547](https://github.com/cylc/cylc-flow/pull/2547) -
[#2552](https://github.com/cylc/cylc-flow/pull/2552) -
[#2564](https://github.com/cylc/cylc-flow/pull/2564) -
User Guide:
 * rewrote the section on restart from state checkpoints
 * rewrote the section on suite run databases
 * new section on suite contact files
 * new section on disaster recovery
 * new section on remote monitoring and control
 * improved terminology:
   * "suite server program" instead of "suite daemon" (it's not always a daemon)
   * "severity" instead of "priority" for logging and task messaging
   * "task remote" to encompass the concept of "the account where a task job
     runs" whether under the same user account or not, on another host or not
 * documented requirements for remote access to suite-parsing and
   file-retrieval commands, including via the GUI; and clarified the same for
   suite client commands
 * documented a known bug in use of parameters in complex graph syntax (and an
   easy workaround) - see the task parameters section
 * documented kill-to-hold behavior of tasks with retries configured

[#2475](https://github.com/cylc/cylc-flow/pull/2475) - suite server program:
separate debug mode from daemonization

[#2485](https://github.com/cylc/cylc-flow/pull/2485) - export task job environment
variables on definition and before assignment, to ensure they are available to
subshells immediately - even in expressions inside subsequent variable
definitions

[#2489](https://github.com/cylc/cylc-flow/pull/2489) -
[#2557](https://github.com/cylc/cylc-flow/pull/2557) -
`cylc gscan` -
 * configurable menubar visibility at start-up
 * grouped suites now retain their grouped status once stopped

[#2515](https://github.com/cylc/cylc-flow/pull/2515) -
[#2529](https://github.com/cylc/cylc-flow/pull/2529) -
[#2517](https://github.com/cylc/cylc-flow/pull/2517) -
[#2560](https://github.com/cylc/cylc-flow/pull/2560) -
`cylc gui`
 * put prompt dialogs above all windows
 * load new-suite log files after switching to another suite via the File menu
 * graph view: reinstate the right-click menu for ghost nodes (lost at cylc-7.5.0)
 * job log files:
   * fix and document the "extra log files" setting
   * add "view in editor" support for extra log files
   * add text-editor functionality to `cylc jobscript`
   * add "preview jobscript" functionality to the GUI

[#2527](https://github.com/cylc/cylc-flow/pull/2527) -
[#2431](https://github.com/cylc/cylc-flow/pull/2431) -
[#2435](https://github.com/cylc/cylc-flow/pull/2435) -
[#2445](https://github.com/cylc/cylc-flow/pull/2445) -
[#2491](https://github.com/cylc/cylc-flow/pull/2491) -
[#2484](https://github.com/cylc/cylc-flow/pull/2484) -
[#2556](https://github.com/cylc/cylc-flow/pull/2556) -
improved parameter support:
 * allow "%d" integer format in parameter templates
 * allow out of range parameter on graph RHS
 * allow positive offset for parameter index on graph
 * allow negative integer parameters
 * allow custom templating of parameter environment variables, in addition to
   the built-in `CYLC_TASK_PARAM\_&lt;param-name&gt;`
 * allow bare parameter values as task names
 * allow explicit parameter values in "inherit" items under "[runtime]"
 * fix parameters inside (as opposed to beginning or end) of family names
 * fixed inheritance from multiple parameterized namespaces at once

[#2553](https://github.com/cylc/cylc-flow/pull/2553) - upgraded the bundled Jinja2
version to 2.10. This fixes the block scope problem introduced in the previous
version

[#2558](https://github.com/cylc/cylc-flow/pull/2558) - new options to print out JSON
format from `cylc show` and `cylc scan`

### Fixes

[#2381](https://github.com/cylc/cylc-flow/pull/2381) - validation: fail bad event
handler argument templates

[#2416](https://github.com/cylc/cylc-flow/pull/2416) - validation: print the problem
namespace in case of bad multiple inheritance

[#2426](https://github.com/cylc/cylc-flow/pull/2426) - validation: fail
non-predefined config item names (e.g. batch scheduler directives) that contain
multiple consecutive spaces (to ensure that hard-to-spot whitespace typos don't
prevent repeated items from overriding as intended)

[#2432](https://github.com/cylc/cylc-flow/pull/2432) - fixed an issue that could
cause HTTPS client failure due to SSL certificate host name mismatch

[#2434](https://github.com/cylc/cylc-flow/pull/2434) - correctly strip "at TIME"
from the end of multi-line task messages

[#2440](https://github.com/cylc/cylc-flow/pull/2440) - `cylc suite-state`
- fixed DB query of tasks with custom outputs that have not been generated yet

[#2444](https://github.com/cylc/cylc-flow/pull/2444) - added `cylc
report-timings` to main command help

[#2449](https://github.com/cylc/cylc-flow/pull/2449):
 * server suite and task URLs from suite server programs, rather than parsing
   them from the suite definition - so browsing URLs from a remote GUI now
   works
 * allow proper string templating of suite and task names in URLs; retained the
   old pseudo environment variables for backward compatibility

[#2461](https://github.com/cylc/cylc-flow/pull/2461) - fixed manual task retrigger
after an aborted edit run - this was erroneously using the edited job file

[#2462](https://github.com/cylc/cylc-flow/pull/2462) - fixed job polling for the SGE
batch scheduler

[#2464](https://github.com/cylc/cylc-flow/pull/2464) - fixed the ssh+HTTPS task
communication method (broken at cylc-7.5.0)

[#2467](https://github.com/cylc/cylc-flow/pull/2467) - fixed an error in reverse
date-time subtraction (first\_point - last\_point)

[#2474](https://github.com/cylc/cylc-flow/pull/2474) - `cylc graph` -
better handle suite parsing errors on view refresh

[#2496](https://github.com/cylc/cylc-flow/pull/2496) - ensure that broadcasted
environment variables are defined before all user-defined variables, which may
need to reference the broadcasted ones

[#2523](https://github.com/cylc/cylc-flow/pull/2523) - fixed a problem with suicide
triggers: with several used at once, tasks could go untriggered

[#2546](https://github.com/cylc/cylc-flow/pull/2546) - fixed problems with stop
point after a suite reload: do not reset an existing stop point (this is
dangerous, but it could be done before, and the stop point in the GUI status
bar would still refer to the original)

[#2562](https://github.com/cylc/cylc-flow/pull/2562) - improved advice on how to
generate an initial user config file (`global.rc`)

-------------------------------------------------------------------------------
## __cylc-7.5.0 (2017-08-29)__

### Enhancements

[#2387](https://github.com/cylc/cylc-flow/pull/2387),
[#2330](https://github.com/cylc/cylc-flow/pull/2330): New suite.rc `[meta]` sections
for suite and task metadata. These hold the existing `title`, `description`,
and `URL` items, plus arbitrary user-defined items. Metadata items can be passed
to event handlers (e.g. a site-specific task "priority" or "importance" rating
could inform an event-handler's decision on whether or not to escalate task
failures).

[#2298](https://github.com/cylc/cylc-flow/pull/2298),
[#2401](https://github.com/cylc/cylc-flow/pull/2401): New shell function
`cylc__job_abort <message>` to abort task job scripts with a custom message
that can be passed to task failed event handlers.

[#2204](https://github.com/cylc/cylc-flow/pull/2204): Remove auto-fallback to HTTP
communications, if HTTPS is not available.  Now HTTP is only used if explicitly
configured.

[#2332](https://github.com/cylc/cylc-flow/pull/2332),
[#2325](https://github.com/cylc/cylc-flow/pull/2325),
[#2321](https://github.com/cylc/cylc-flow/pull/2321),
[#2312](https://github.com/cylc/cylc-flow/pull/2312): Validation efficiency
improvements.

[#2291](https://github.com/cylc/cylc-flow/pull/2291),
[#2303](https://github.com/cylc/cylc-flow/pull/2303),
[#2322](https://github.com/cylc/cylc-flow/pull/2322): Runtime efficiency
improvements.

[#2286](https://github.com/cylc/cylc-flow/pull/2286): New command `cylc
report-timings` to generate reports of task runtime statistics.

[#2304](https://github.com/cylc/cylc-flow/pull/2304): New event handlers for general
CRITICAL events.

[#2244](https://github.com/cylc/cylc-flow/pull/2244),
[#2258](https://github.com/cylc/cylc-flow/pull/2258): Advanced syntax for excluding
multiple points from cycling sequences.

[#2407](https://github.com/cylc/cylc-flow/pull/2407): Documented exactly how Cylc
uses ssh, scp, and rsync to interact with remote job hosts.

[#2346](https://github.com/cylc/cylc-flow/pull/2346),
[#2386](https://github.com/cylc/cylc-flow/pull/2386): `cylc graph` now plots
implicit dependences as grayed-out ghost nodes.

[#2343](https://github.com/cylc/cylc-flow/pull/2343): Improved the "Running
Suites" section of the User Guide, including documentation of suite remote
control.

[#2344](https://github.com/cylc/cylc-flow/pull/2344): Attempt to access suite
service files via the filesystem first, before ssh, for other accounts on the
suite host.

[#2360](https://github.com/cylc/cylc-flow/pull/2360): Better validation of suite
parameter configuration.

[#2314](https://github.com/cylc/cylc-flow/pull/2314): In debug mode, send bash job
script xtrace output (from `set -x`) to a separate log file.

### Fixes

[#2409](https://github.com/cylc/cylc-flow/pull/2409): Fixed the `cylc spawn` command
(it was killing tasks, since cylc-7).

[#2378](https://github.com/cylc/cylc-flow/pull/2378): Fixed use of negative offsets
by the `cylc suite-state` command.

[#2364](https://github.com/cylc/cylc-flow/pull/2364): Correctly load completed custom
task outputs on restart.

[#2350](https://github.com/cylc/cylc-flow/pull/2350): Handle bad event handler
command line templates gracefully.

[#2308](https://github.com/cylc/cylc-flow/pull/2308): The parameterized task
environment variable `$CYLC_TASK_PARAM_<param>` is now guaranteed to be defined
before any use of it in the user-defined task environment section.

[#2296](https://github.com/cylc/cylc-flow/pull/2296): Prevent suites stalling after
a restart that closely follows a warm-start (now the restart, like the warm
start, ignores dependence on tasks from before the warm start point).

[#2295](https://github.com/cylc/cylc-flow/pull/2295): Fixed `cylc cat-log` "open in
editor" functionality for remote job logs.

[#2412](https://github.com/cylc/cylc-flow/pull/2412): Fixed duplication of log
messages to the old log after restart.

-------------------------------------------------------------------------------

## __cylc-7.4.0 (2017-05-16)__

Enhancements and fixes.

### Highlighted Changes

[#2260](https://github.com/cylc/cylc-flow/pull/2260): Open job logs in your text
editor, from CLI (`cylc cat-log`) or GUI.

[#2259](https://github.com/cylc/cylc-flow/pull/2259): `cylc gscan` - various
improvements: right-click menu is now for suite operations only; other items
moved to a main menubar and toolbar (which can be hidden to retain gscan's
popular minimalist look); added all suite stop options (was just the default
clean stop); task-state colour-key popup updates in-place if theme changed; new
collapse/expand-all toobar buttons.

[#2275](https://github.com/cylc/cylc-flow/pull/2275): Pass suite and task URLs to
event handlers.

[#2272](https://github.com/cylc/cylc-flow/pull/2272): Efficiency - reduce memory
footprint.

[#2157](https://github.com/cylc/cylc-flow/pull/2157):
  * internal efficiency improvements
  * allow reset of individual message outputs
  * "cylc submit" can now submit families

[#2244](https://github.com/cylc/cylc-flow/pull/2244): Graph cycling configuration:
multiple exclusion points.

[#2240](https://github.com/cylc/cylc-flow/pull/2240): Stepped integer parameters.

### Fixes

[#2269](https://github.com/cylc/cylc-flow/pull/2269): Fix auto suite-polling tasks
(i.e. inter-suite dependence graph syntax) - Broken in 7.3.0.

[#2282](https://github.com/cylc/cylc-flow/pull/2282): Fix global config processing
of boolean settings - users could not override a site True setting to False.

[#2279](https://github.com/cylc/cylc-flow/pull/2279): Bundle Jinja2 2.9.6. (up from
2.8) - fixes a known issue with Jinja2 "import with context".

[#2255](https://github.com/cylc/cylc-flow/pull/2255): Fix handling of suite script
items that contain nothing but comments.

[#2247](https://github.com/cylc/cylc-flow/pull/2247): Allow `cylc graph --help`
in the absence of an X environment.

### Other Changes

[#2270](https://github.com/cylc/cylc-flow/pull/2270): Detect and fail null tasks in
graph.

[#2257](https://github.com/cylc/cylc-flow/pull/2257): `cylc gscan` - graceful exit
via Ctrl-C.

[#2252](https://github.com/cylc/cylc-flow/pull/2252): `ssh`: add `-Y` (X Forwarding)
only if necessary.

[#2245](https://github.com/cylc/cylc-flow/pull/2245): SSL certificate: add serial
number (issue number). This allows curl, browsers, etc. to connect to
suite daemons.

[#2265](https://github.com/cylc/cylc-flow/pull/2265): `cylc gpanel` - restored
sorting of items by suite name.

[#2250](https://github.com/cylc/cylc-flow/issues/2250): Updated installation docs
for HTTPS-related requirements.

-------------------------------------------------------------------------------
## __cylc-7.3.0 (2017-04-10)__

New Suite Design Guide, plus other enhancements and fixes.

### Highlighted Changes

[#2211](https://github.com/cylc/cylc-flow/pull/2211): New comprehensive Suite Design
Guide document to replace the outdated Suite Design section in the User Guide.

[#2232](https://github.com/cylc/cylc-flow/pull/2232): `cylc gscan` GUI: stop, hold,
and release suites or groups of suites.

[#2220](https://github.com/cylc/cylc-flow/pull/2220): dummy and simulation mode improvements:
 * new `dummy-local` mode runs dummy tasks as local background jobs (allows
   dummy running other-site suites).
 * proportional run length, if tasks configure an `execution time limit`
 * single common `[simulation]` configuration section for dummy, dummy-local, and
   simulation modes.
 * dummy or simulated tasks can be made to fail at specific cycle points, and
   for first-try only, or all tries.
 * custom message outputs now work in simulation mode as well as the dummy modes.

[#2218](https://github.com/cylc/cylc-flow/pull/2218): fix error trapping in job
scripts (degraded since job file refactoring in 7.1.1)

[#2215](https://github.com/cylc/cylc-flow/pull/2215): SGE batch system support -
fixed formatting of directives with a space in the name.

### Other Notable Changes

[#2233](https://github.com/cylc/cylc-flow/pull/2233): Upgraded the built-in example
suites to cylc-7 syntax.

[#2221](https://github.com/cylc/cylc-flow/pull/2221): `cylc gui` GUI dot view - maintain
user selection during update.

[#2217](https://github.com/cylc/cylc-flow/pull/2217): `cylc gscan` GUI - fix
tracebacks emitted during suite initialization.

[#2219](https://github.com/cylc/cylc-flow/pull/2219): add `user@host` option to
`cylc monitor` an `cylc gui`. Allows suite selection at startup using `cylc
scan` output.

[#2222](https://github.com/cylc/cylc-flow/pull/2222): `cylc gui` GUI graph view -
fixed right-click "view prerequisites" sub-menu.

[#2213](https://github.com/cylc/cylc-flow/pull/2213): Record family inheritance
structure in the run database.

-------------------------------------------------------------------------------
## __cylc-7.2.1 (2017-03-23)__

Minor enhancements and fixes.

### Highlighted Changes

[#2209](https://github.com/cylc/cylc-flow/pull/2209): Fixed the `cylc gui` graph
view, broken at cylc-7.2.0.

[#2193](https://github.com/cylc/cylc-flow/pull/2193): Restored `cylc gscan`
suite-stopped status checkerboard icons, lost at cylc-7.1.1.


[#2208](https://github.com/cylc/cylc-flow/pull/2208): Use suite host name instead
of suite name in the SSL certificate "common name".

[#2206](https://github.com/cylc/cylc-flow/pull/2206): Updated User Guide
installation section.

### Other Notable Changes

[#2191](https://github.com/cylc/cylc-flow/pull/2191): Clearer task prerequisites
print-out.

[#2197](https://github.com/cylc/cylc-flow/pull/2197): Removed the bundled external
OrderedDict package.

[#2194](https://github.com/cylc/cylc-flow/pull/2194): `cylc gscan` - better handling
of suites that are still initializing.

-------------------------------------------------------------------------------
## __cylc-7.2.0 (2017-03-06)__

Minor enhancements and fixes (note mid-level version number bumped up to
reflect significant changes included in 7.1.1 - esp. job file refactoring).

### Highlighted Changes

[#2189](https://github.com/cylc/cylc-flow/pull/2189): New `assert` and
`raise` functions for handling Jinja2 errors in suites.

### Other Changes

[#2186](https://github.com/cylc/cylc-flow/pull/2186): Use lowercase local shell
variable names in new job script shell functions introduced in 7.1.1, to avoid
overriding shell built-ins such as `$HOSTNAME`.

[#2187](https://github.com/cylc/cylc-flow/pull/2187): Fixed a bug causing restart
failure in the presence of an active broadcast of a submission timeout value.

[#2183](https://github.com/cylc/cylc-flow/pull/2183): Use site-configured suite host
self-identification, if present, as hostname in the SSL certificate.

[#2182](https://github.com/cylc/cylc-flow/pull/2182): Fixed failed User Guide build
in 7.1.1.

-------------------------------------------------------------------------------
## __cylc-7.1.1 (2017-02-27)__

Minor enhancements and fixes (plus a significant change: task job file refactoring).

### Highlighted Changes

[#2141](https://github.com/cylc/cylc-flow/pull/2141): Tidier task job files:
hide error trap and messaging code, etc., in external shell functions.

[#2134](https://github.com/cylc/cylc-flow/pull/2134): Suite-state polling (e.g. for
inter-suite triggering) now automatically detects and uses the remote suite
cycle point format.

[#2128](https://github.com/cylc/cylc-flow/pull/2128): Suite-state polling
(e.g. for inter-suite triggering) now works with custom task messages.

[#2172](https://github.com/cylc/cylc-flow/pull/2172): Added a built-in Jinja2 filter
for formatting ISO8601 date-time strings.

[#2164](https://github.com/cylc/cylc-flow/pull/2164): Fixed support for Jinja2 in
site/user config files, broken at 6.11.0.

[#2153](https://github.com/cylc/cylc-flow/pull/2153): `cylc gui` - use task
`execution time limit` as the default mean elapsed time, to compute a progress
bar for the first instance of a cycling task.

[#2154](https://github.com/cylc/cylc-flow/pull/2154): `cylc gui` graph view - fixed
right-click sub-menu activation, broken at 7.1.0.

[#2158](https://github.com/cylc/cylc-flow/pull/2158): `cylc gui` graph view: fix
right-click family ungroup, broken since 7.0.0.

### Other Changes

[#2142](https://github.com/cylc/cylc-flow/pull/2142): New "select all" and "select
none" buttons in the `cylc gui` task filter dialog.

[#2163](https://github.com/cylc/cylc-flow/pull/2163): (Development) New automated
profiling test framework for comparing performance between Cylc versions.

[#2160](https://github.com/cylc/cylc-flow/pull/2160): Better suite stall detection
in the presence of clock-triggered tasks.

[#2156](https://github.com/cylc/cylc-flow/pull/2156): Fix potential division-by-zero
error in `cylc gscan`.

[#2149](https://github.com/cylc/cylc-flow/pull/2149): Fix handling of cycle point
offsets in weeks (e.g. "P1W").

[#2146](https://github.com/cylc/cylc-flow/pull/2146): Documented how to set multiple
`-l VALUE` directives in jobs submitted to PBS.

[#2129](https://github.com/cylc/cylc-flow/pull/2129): Allow initial cycle point to be
specified on the command line for all relevant commands, if not specified in the
suite definition.

[#2139](https://github.com/cylc/cylc-flow/pull/2139): Fixed error in use of
`execution time limit` in jobs submitted to Platform LSF.

[#2176](https://github.com/cylc/cylc-flow/pull/2176): `cylc gui` graph view - fixed
a bug that could cause a blank graph view window, since 7.0.0.

[#2161](https://github.com/cylc/cylc-flow/pull/2161): `gcylc gui`- disallow
insertion at cycle points that are not valid for the task (unless overridden
with `--no-check`).

-------------------------------------------------------------------------------
## __cylc-7.1.0 (2017-01-26)__

Minor enhancements and fixes.

### Highlighted Changes

[#2021](https://github.com/cylc/cylc-flow/pull/2021): New command `cylc checkpoint`
to create a named suite state checkpoint that you can restart from.

[#2124](https://github.com/cylc/cylc-flow/pull/2124): open another GUI window (to
view another suite) via the gcylc File menu.

[#2100](https://github.com/cylc/cylc-flow/pull/2100): group multiple task event
notifications into a single email over a 5 minute interval (configurable).

[#2112](https://github.com/cylc/cylc-flow/pull/2112): broadcast settings can now be
loaded (or cancelled) from a file as well as the command line.

[#2096](https://github.com/cylc/cylc-flow/pull/2096): the `cylc gscan` GUI can now
display summary states for suites owned by others.

### Other Changes

[#2126](https://github.com/cylc/cylc-flow/pull/2126): fixed occasional
misidentification of suite stall when only succeeded tasks exist just prior to
shutdown.

[#2127](https://github.com/cylc/cylc-flow/pull/2127): fixed the `cylc diff` command
(broken at 7.0.0)

[#2119](https://github.com/cylc/cylc-flow/pull/2119): fixed remote job kill after a
suite definition reload, for task proxies that exist at the time of the reload.

[#2025](https://github.com/cylc/cylc-flow/pull/2025): GUI right-click menu items can
now be selected with either mouse button 1 or 3.

[#2117](https://github.com/cylc/cylc-flow/pull/2117): improved logic for adding
`lib/cylc` to Python `sys.path` (there was one reported instance of the
system-level `cherrpy` being imported instead of the Cylc-bundled one, in
cylc-7.0.0).

[#2114](https://github.com/cylc/cylc-flow/pull/2114): documented syntax-driven line
continuation in suite graph configuration.

[#2116](https://github.com/cylc/cylc-flow/pull/2116): corrected a rare edge-case
side-effect of manual task-state reset.

[#2107](https://github.com/cylc/cylc-flow/pull/2107): `cylc insert` - disallow
insertion at cycle points that are not valid for the task (unless overridden
with `--no-check`).

[#2106](https://github.com/cylc/cylc-flow/pull/2106): fixed `cylc get-config
--python` output formatting, broken since cylc-6.6.0.

[#2097](https://github.com/cylc/cylc-flow/pull/2097): fixed a problem with task host
and owner task proxies reloaded at suite restart (could cause job poll and
kill to fail in some cases, for tasks in this category).

[#2095](https://github.com/cylc/cylc-flow/pull/2095): fixed validation of mixed
deprecated and new suite.rc syntax.

## __cylc-7.0.0 (2016-12-21)__

**cylc-7 client/server communications is not backward compatible with cylc-6.**

Note that cylc-7 bug fixes were back-ported to a series of 6.11.x releases,
for those who have not transitioned to cylc-7 yet.

### Highlighted Changes

[#1923](https://github.com/cylc/cylc-flow/pull/1923): **A new HTTPS communications
layer, replaces Pyro-3 Object RPC for all client-server communications.**
Suite daemons are now web servers!

[#2063](https://github.com/cylc/cylc-flow/pull/2063): **Removed deprecated cylc-5
syntax and features.**

[#2044](https://github.com/cylc/cylc-flow/pull/2044): Suite start-up now aborts with
a sensible message on suite configuration errors (previously this happened post
daemonization so the user had to check suite logs to see the error).

[#2067](https://github.com/cylc/cylc-flow/pull/2067): Consolidated suite service
files (passphrase, SSL files, contact file, etc.) under `.service/` in the
suite run directory; the suite registration database and port files under
`$HOME/.cylc/` are no longer used; suites can now be grouped in sub-directory
trees under the top level run directory.

[#2033](https://github.com/cylc/cylc-flow/pull/2033): Allow restart from suite state
checkpoints other than the latest (checkpoints are also recorded automatically
before and after restarts, and on reload).

[#2024](https://github.com/cylc/cylc-flow/pull/2024): `cylc gscan` now supports
collapsible suite groups via a top level suite config `group` item.
Right-click *View Column* "Group".

[#2074](https://github.com/cylc/cylc-flow/pull/2074): Task retry states and timers,
and poll timers, now persist across suite restarts. Waiting tasks are not
put in the held state before shutdown. Held tasks are not automatically
released on restart.

[#2004](https://github.com/cylc/cylc-flow/pull/2004): Task event handlers are
now continued on restart.

### Other Changes

[#2042](https://github.com/cylc/cylc-flow/pull/2042): Documented `[scheduling]spawn
to max active cycle points` (new in 6.11.0), which lets successive instances of
the same task run out of order if dependencies allow.

[#2092](https://github.com/cylc/cylc-flow/pull/2092): New command `cylc
get-suite-contact` to print suite contact information (host, port, PID, etc.)

[#2089](https://github.com/cylc/cylc-flow/pull/2089): Improved documentation on
cycling workflows and use of parameterized tasks as a proxy for cycling.

[#2021](https://github.com/cylc/cylc-flow/pull/2021): `cylc gui`: removed the
"connection failed" warning dialog that popped up on suite shutdown. This
should be obvious by the reconnection countdown timer in the info bar.

[#2023](https://github.com/cylc/cylc-flow/pull/2023): New custom event email footer
via global or suite config.

[#2013](https://github.com/cylc/cylc-flow/pull/2013): Fixed "remove task after
spawning" which since 6.9.0 would not force a waiting task to spawn its
successor.

[#2071](https://github.com/cylc/cylc-flow/pull/2071): Fix quote stripping on
`initial cycle point = "now"`.

[#2070](https://github.com/cylc/cylc-flow/pull/2070): Fix dummy mode support for
custom task outputs: they were incorrectly propagated to other tasks.

[#2065](https://github.com/cylc/cylc-flow/pull/2065): `cylc gscan` now supports
suite name filtering via a `--name` command line option.

[#2060](https://github.com/cylc/cylc-flow/pull/2060): 5-second timeout if hanging
connections are encountered during port scanning.

[#2055](https://github.com/cylc/cylc-flow/pull/2055): Task elapsed times now persist
over restarts.

[#2046](https://github.com/cylc/cylc-flow/pull/2046): Multi-task interface for `cylc
show`. Fixed *View Prerequisites* for tasks in the runahead pool.

[#2049](https://github.com/cylc/cylc-flow/pull/2049): Per-host job submission and
execution polling intervals via global/user config files.

[#2051](https://github.com/cylc/cylc-flow/pull/2051): Bundle Jinja2 2.8 with Cylc -
one less external software dependency.

[#2088](https://github.com/cylc/cylc-flow/pull/2088): Support dependence on absolute
cycle points in cycling graphs.

## __cylc-6.11.4 (2017-01-26)__

More bug fixes backported from early Cylc-7 releases.

[#2120](https://github.com/cylc/cylc-flow/pull/2120): fixed remote job kill after a
+suite definition reload, for task proxies that exist at the time of the reload.

[#2111](https://github.com/cylc/cylc-flow/pull/2111): fixed member-expansion of
complex `(FAMILY:fail-any & FAMILYI:finish-all)` graph triggers.

[#2102](https://github.com/cylc/cylc-flow/pull/2102): fixed validation of mixed
deprecated and new suite.rc syntax.

[#2098](https://github.com/cylc/cylc-flow/pull/2098): fixed a problem with task host
and owner task proxies reloaded at suite restart (could cause job poll and
kill to fail in some cases, for tasks in this category).


## __cylc-6.11.3 (2016-12-21)__

One minor bug fix on top of 6.11.2.

[#2091](https://github.com/cylc/cylc-flow/pull/2091): Since 6.11.0 use of cylc-5
special "cold start tasks" caused downstream tasks to become immortal. This
fixes the problem, but note that you should no longer be using this deprecated
feature (which will be removed from cylc-7).


## __cylc-6.11.2 (2016-10-19)__

Some minor enhancements and fixes.

### Highlighted Changes

[#2034](https://github.com/cylc/cylc-flow/pull/2034): Allow restart from checkpoints.
These are currently created before and after reloads, and on restart. (Note that
since 6.11.0 suite state dump files no longer exist).

[#2047](https://github.com/cylc/cylc-flow/pull/2047): Documented the new
"[scheduling]spawn to max active cycle points" suite configuration item,
which allows successive instances of the same task to run out of order if the
opportunity arises.

[#2048](https://github.com/cylc/cylc-flow/pull/2048): Allow "view prerequisites" for
tasks in the 'runahead' state.

[#2025](https://github.com/cylc/cylc-flow/pull/2025): Provide a configurable event
mail footer (suite or site/user configuration).

[#2032](https://github.com/cylc/cylc-flow/pull/2032): `cylc gui` -
removed the annoying warning dialog for connection failed. Take note of the
connection countdown in the status bar instead.

### Other Changes

[#2016](https://github.com/cylc/cylc-flow/pull/2016): Fixed a Python traceback
occasionally generated by the gcylc GUI log view window.

[#2018](https://github.com/cylc/cylc-flow/pull/2018): Restored the incremental
printing of dots to stdout from the `cylc suite-state` polling
command (lost at 6.11.1).

[#2014](https://github.com/cylc/cylc-flow/pull/2014): Fixed "remove after spawning".
Since 6.9.0 this would not force-spawn the successor of a waiting task.

[#2031](https://github.com/cylc/cylc-flow/pull/2031): `cylc gscan` -
fixed occasional jumping status icons introduced in 6.11.1.

[#2040](https://github.com/cylc/cylc-flow/pull/2040): Corrected documentation for
the `cylc cat-log` command (it was using the alias `cylc
log`).


## __cylc-6.11.1 (2016-09-22)__

Three minor bug fixes on top of 6.11.0:

[#2002](https://github.com/cylc/cylc-flow/pull/2002): fix a bug in the graph string
parser - if a task appears both with and without a cycle point offset in the
same conditional trigger expression (unlikely, but possible!)

[#2007](https://github.com/cylc/cylc-flow/pull/2007): fix handling of OS Error if
the user run into the limit for number of forked processes.

[#2008](https://github.com/cylc/cylc-flow/pull/2008): fix occasional traceback from
`cylc gsan`.



## __cylc-6.11.0 (2016-09-13)__

### Highlighted Changes

[#1953](https://github.com/cylc/cylc-flow/pull/1953): Parameterized tasks: generate
tasks automatically without using messy Jinja2 loops.

[#1929](https://github.com/cylc/cylc-flow/pull/1929): Under `[runtime]`:
 * New task `[[[job]]]` sub-sections unify the various batch system, job
   execution, and job polling settings (older settings deprecated).
 * A new `[[[job]]] execution time limit` setting allows cylc to:
    * automatically generate batch system time limit directives;
    * run background or at jobs with the `timeout` command;
    * poll job with configurable delays (default 1, 3, 10 minutes) after
      reaching the time limit.
 * Moved the content of the old `[event hooks]` section to a unified `[events]`
   section (older settings deprecated).

[#1884](https://github.com/cylc/cylc-flow/pull/1884): `cylc gscan` displays a new
warning icon with a tool-tip summary of recent task failures.

[#1877](https://github.com/cylc/cylc-flow/pull/1877): The `gcylc` status bar now
shows a countdown to the next suite connection attempt, and resets the
connection timer schedule if the user changes view settings.

[#1966](https://github.com/cylc/cylc-flow/pull/1966): Optionally spawn waiting tasks
out to "max active cycle points" instead of one cycle point ahead. This means
successive instances of the same task can run out of order (dependencies
allowing).  Use with caution on large suites with a lot of runahead.

[#1940](https://github.com/cylc/cylc-flow/pull/1940): Bash tab completion for cylc
commands.

### Other Changes

[#1585](https://github.com/cylc/cylc-flow/pull/1585): If a suite stalls, report any
unsatisfied task prerequisites that cannot be met.

[#1944](https://github.com/cylc/cylc-flow/pull/1944): `cylc get-config` now returns
a valid suite definition.

[#1875](https://github.com/cylc/cylc-flow/pull/1875): Enabled multiple selection in
the gcylc text tree view.

[#1900](https://github.com/cylc/cylc-flow/pull/1900): Automatically continue graph
string lines that end in (or start with) a dependency arrow.

[#1862](https://github.com/cylc/cylc-flow/pull/1862): New notation for initial and
final cycle point in graph cycling section headings.  E.g. `[[[R1/^+PT1H]]]`
means "run once, one hour after the initial cycle point"; `[[[R1/$-PT1H]]]`
means "run once, one hour before the final cycle point".

[#1928](https://github.com/cylc/cylc-flow/pull/1928): New notation for excluding a
cycle point from a recurrence expression, e.g. `[[[T00!^]]]` means
"daily at T00 after but not including the initial cycle point".

[#1958](https://github.com/cylc/cylc-flow/pull/1958): Suite daemon logging upgrade:
improved log file formatting; the log, out, and err files are now rolled over
together as soon as any one reaches the size limit.

[#1827](https://github.com/cylc/cylc-flow/pull/1827): Suite state dump files no
longer exist - the suite run DB now records all restart information.

[#1912](https://github.com/cylc/cylc-flow/pull/1912): Fixed coloured `cylc scan -c`
output (broken at 6.10.1).

[#1921](https://github.com/cylc/cylc-flow/pull/1921): Don't ignore dependencies
among tasks back-inserted prior to a warm-start cycle point.

[#1910](https://github.com/cylc/cylc-flow/pull/1910): Task job scripts now use `set
-o pipefail` to ensure that failure of any part of a shell pipeline causes a
job failure.

[#1886](https://github.com/cylc/cylc-flow/pull/1886): When a job is submitted for
the first time, any job logs with higher submit numbers will be removed (
these must have been generated by a previous suite run).

[#1946](https://github.com/cylc/cylc-flow/pull/1946): Removed annoying warnings
that "self-suicide is not recommended".

[#1889](https://github.com/cylc/cylc-flow/pull/1889): Record any unhandled task
messages (e.g. general progress messages) in the suite DB.

[#1899](https://github.com/cylc/cylc-flow/pull/1899): Custom task output messages
(for message triggers) are now automatically faked in dummy mode.

-------------------------------------------------------------------------------

## __cylc-6.10.2 (2016-06-02)__

### Highlighted Changes

[#1848](https://github.com/cylc/cylc-flow/pull/1848): Automatic stalled-suite
detection, a "stalled" event hook, and an option to abort (shutdown) if stalled.

[#1850](https://github.com/cylc/cylc-flow/pull/1850): Much reduced CPU loading in
cycling suites that have progressed far beyond their initial cycle point (cache
recent points to avoid continually iterating from the start).

[#1836](https://github.com/cylc/cylc-flow/pull/1836): New `gscan.rc` file to
configure the initial state of `cylc gpanel` and `cylc gscan` (e.g. which
columns to display).

[#1849](https://github.com/cylc/cylc-flow/pull/1849): New configuration options for
the `gcylc` GUI, e.g. to set the initial window size.


### Other Changes

[#1863](https://github.com/cylc/cylc-flow/pull/1863): Report tasks added or removed
by a suite reload.

[#1844](https://github.com/cylc/cylc-flow/pull/1844): Allow client commands from
another suite's task (these would previously load the passphrase for the parent
suite rather than the target suite).

[#1866](https://github.com/cylc/cylc-flow/pull/1866): Allow explicitly unset
intervals in cylc config files, e.g. `execution timeout = # (nothing)`.

[#1863](https://github.com/cylc/cylc-flow/pull/1863): Fixed a recent bug (since in
6.10.0) causing shutdown on reload of a suite after removing a task and its
runtime definition.

[#1864](https://github.com/cylc/cylc-flow/pull/1864): Stronger checks to prevent
users starting a second instance of a suite that is already running.

[#1869](https://github.com/cylc/cylc-flow/pull/1869): Fixed day-of-week cycling.

[#1858](https://github.com/cylc/cylc-flow/pull/1858): Fixed a recent bug (since
6.10.1) that could prevent a task at suite start-up from submitting even though
its prerequisites were satisfied.

[#1855](https://github.com/cylc/cylc-flow/pull/1855): Allow inserted tasks to be
released to the `waiting` immediately, even if the suite is currently quiet.

[#1854](https://github.com/cylc/cylc-flow/pull/1854): Restore wildcards to
allow insertion of multiple tasks at once (inadvertently disallowed at 6.10.0).

[#1853](https://github.com/cylc/cylc-flow/pull/1853): Fixed a recent bug (since
6.10.1): reset task outputs to incomplete on manually retriggering or resetting
to a pre-run state.

-------------------------------------------------------------------------------

## __cylc-6.10.1 (2016-05-17)__

### Highlighted Changes

[#1839](https://github.com/cylc/cylc-flow/pull/1839): `gcylc` - fix for occasional
locked-up blank GUI window at start-up (since 6.8.0, Jan 2016).

[#1841](https://github.com/cylc/cylc-flow/pull/1841): `gcylc` tree view - fix for
excessive CPU load when displaying large suites (since 6.10.0).

[#1838](https://github.com/cylc/cylc-flow/pull/1838): Fix for the suite timeout
event timer not resetting on task activity (since 6.10.0).

### Other Changes

[#1835](https://github.com/cylc/cylc-flow/pull/1835): Suite reload - reload all
tasks at once (previously, current active tasks were reloaded only when they
finished, which could result in reloads appearing to take a long time).

[#1833](https://github.com/cylc/cylc-flow/pull/1833): `gcylc` - initial task state
filtering configurable via the  `gcylc.rc` config file.

[#1826](https://github.com/cylc/cylc-flow/pull/1826): Prevent tasks becoming immune
to change by suite reload after being orphaned by one reload (i.e. removed from
the suite) then re-inserted after another.

[#1804](https://github.com/cylc/cylc-flow/pull/1804): PBS job name length - truncate
to 15 characters by default, but can now be configured in `global.rc` for PBS
13+, which supports longer names.

-------------------------------------------------------------------------------

## __cylc-6.10.0 (2016-05-04)__

### Highlighted Changes

[#1769](https://github.com/cylc/cylc-flow/pull/1769),
[#1809](https://github.com/cylc/cylc-flow/pull/1809),
[#1810](https://github.com/cylc/cylc-flow/pull/1810),
[#1811](https://github.com/cylc/cylc-flow/pull/1811),
[#1812](https://github.com/cylc/cylc-flow/pull/1812),
[#1813](https://github.com/cylc/cylc-flow/pull/1813),
[#1819](https://github.com/cylc/cylc-flow/pull/1819): Suite daemon efficiency
and memory footprint - significant improvements!

[#1777](https://github.com/cylc/cylc-flow/pull/1777): Faster validation of
suites with large inter-dependent families.  See also
[#1791](https://github.com/cylc/cylc-flow/pull/1791).

[#1743](https://github.com/cylc/cylc-flow/pull/1743): Improved event handling:
flexible handlers, built-in email handlers, execute event handlers
asynchronously, general suite event handlers.

[#1729](https://github.com/cylc/cylc-flow/pull/1729): `gcylc` - The *File -> Open*
dialog can now connect to suites running on other scanned hosts.

[#1821](https://github.com/cylc/cylc-flow/pull/1821): Right-click on a cycle-point
in the `gcylc` text tree view to operate on all tasks at that cycle point.

### Other Changes

[#1714](https://github.com/cylc/cylc-flow/pull/1714): Further improvements to Jinja2
error reporting.

[#1755](https://github.com/cylc/cylc-flow/pull/1755): Pyro-3.16 is now packaged with
with cylc and has been modified to reduce the overhead of repeated calls to
`socket.gethost*`. We will eventually replace it with a new client/server
communications layer.

[#1807](https://github.com/cylc/cylc-flow/pull/1807): Dropped support for
_detaching_ (or _manual completion_) tasks.

[#1805](https://github.com/cylc/cylc-flow/pull/1805): `gcylc` - corrected the suite
hold/release button state during  active suite reloads.

[#1802](https://github.com/cylc/cylc-flow/pull/1802): Do not unregister running
suites or assume that the argument of `cylc unregister` is a pattern.

[#1800](https://github.com/cylc/cylc-flow/pull/1800): Print a sensible error message
for a suite graph section with a zero-width cycling interval.

[#1791](https://github.com/cylc/cylc-flow/pull/1791): Documented how to write suites
with efficient inter-family triggering.

[#1789](https://github.com/cylc/cylc-flow/pull/1789): Fixed a bug causing high CPU
load in large suites with `queued` tasks present.

[#1788](https://github.com/cylc/cylc-flow/pull/1788): Fixed a bug that could
occasionally result in missing entries in suite run databases.

[#1784](https://github.com/cylc/cylc-flow/pull/1784): Corrected and improved the
advice printed at start-up on how to see if a suite is still running.

[#1781](https://github.com/cylc/cylc-flow/pull/1781): Fixed a bug that could disable
the right-click menu for some tasks after enabling a filter.

[#1768](https://github.com/cylc/cylc-flow/pull/1768): Client commands like `cylc
broadcast` can now be invoked by tasks on hosts that do not share a
filesystem with the suite host.

[#1763](https://github.com/cylc/cylc-flow/pull/1763): Remote tasks now load
the right suite passphrase even if a locally registered suite has
the same name.

[#1762](https://github.com/cylc/cylc-flow/pull/1762): Fixed polling of jobs
submitted to loadleveler (broken since 6.8.1).

[#1816](https://github.com/cylc/cylc-flow/pull/1816),
[#1779](https://github.com/cylc/cylc-flow/pull/1779): Allow task names that contain
family names after a hyphen.

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#### For changes prior to cylc-6.10.0 see doc/changes.html in the cylc source tree.
