Deprecate Conditions CRD

[jerop]

With the implementation of Conditions Beta, specifically WhenExpressions, we want to deprecate the Conditions CRD because:

• Efficiency: Conditions have to spin up new Pods for every check, even simple ones. WhenExpressions enable guarding Tasks with simple checks without spinning up new Pods. Read more.
• Simplicity: Conditions actually manifested themselves as Tasks. In more complex use cases, we can use Tasks themselves to produce Results that can be used to specify WhenExpressions in subsequent Tasks. Read more.
• Flexibility: When Conditions evaluated to False and the associated Task was skipped, the subsequent Tasks were skipped as well. Tasks guarded by WhenExpressions support passing in a field -continueAfterSkip - that enables ordering-dependent Tasks to execute when it is set to True. Read more.
• Status: It is difficult to distinguish Conditions causing a Task to be skipped or the Task failing for other reasons. When WhenExpressions evaluate to false, the associated Task is listed in a Skipped Tasks section of the status alongside the resolved WhenExpressions. If they evaluate to True, the resolved WhenExpressions are listed alongside the TaskRun status. Read more.

Conditions CRD has been listed in the deprecations table since the release of v0.16.0.

This is a milestone for release of Pipelines v1beta2.

cc @bobcatfish

[jerop]

/kind cleanup

[tekton-robot]

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/lifecycle stale

Send feedback to tektoncd/plumbing.

[vdemeester]

/remove-lifecycle stale
/lifecycle frozen
/area roadmap

[afrittoli]

@jerop @vdemeester @bobcatfish Do we need a v1beta2 to remove Conditions?
They have been deprecated since v0.16.0 and we Nov 2020 was the first time we could have removed them according to the policy.

[jerop]

I don't think it's worth the effort to create v1beta2 just to remove Conditions, especially given that we're already working towards v1 which won't have Conditions - TEP-0096