Merge branch 'stable-3.1' into stable-3.2
* stable-3.1: (38 commits)
docker: make sure to cleanup containers before force exit
fixup! Add TaskTree definitions more directly
fixup! refactor predicate cache into its own class
fixup! Add support for tasks-factory and names-factory keywords
fixup! Support outputting elapsed evaluation time on tasks
fixup! Revert "Revert "plugin:task Adds support for names-factory of type change""
Add a Container.toString() to help when debugging.
Harden inputs to basename
Add Zuul postflight publish job
Pass around Task parent instead of its fields
Fix to alter change context for TaskChangeFactories
Add tasks-factories static properties tests
Add a names-factory STATIC Properties test
Add ensures to the task tests setups
Split the task preload properties test out
Split the task preload optional test out
Split the append preloaded subtasks test out
Split the task override preload pass/fail tests out
Split the task preload hints tests out
Split the task preload preload test out
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Change-Id: I68fefcfe1a0f96fee6d0bcea18060852291f973d
