Add predicate queued to taskRun to indicate that task is planned to be started in future

[BaLiKfromUA]

Changes

Closes #305

This PR introduces a new taskRun predicate: queued.

Consistent with other queued events, this predicate indicates that a task is waiting for the applicable preconditions to be satisfied before it can start running.

This is needed for two reasons:

1. There is currently a small inconsistency between the predicates available for taskRun and the kinds of work that a task can represent. The testSuiteRun subject from Testing Events already supports a queued predicate. Since a task can represent a test run, adding queued to taskRun seems consistent with the specification:

   ...a set of Tasks to be performed, like performing a build, running some tests, publishing an artifact.

2. There is currently no way to express a taskRun that has been scheduled for future execution but has not started yet. For example, a pipelineRun may already be started and in progress while one of its taskRuns is still queued.

   Note: As of July 2026, there is an ongoing discussion about introducing a separate Scheduler abstraction in CDEvents. Such an addition would not conflict with this PR. In the meantime, the queued predicate can serve as a practical compromise.

As an example for making this contribution, I've been using #145

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• Has the primer doc been updated if a design decision is involved
• Have the JSON schemas been updated if the specification changed
• Has spec version and event versions been updated according to the versioning policy
• Meets the CDEvents contributor standards

[BaLiKfromUA]

Validated JSONs locally:

>  cd tools && npm ci && npm run validate
....
taskrun queued: valid
....
50 out of 50 examples are valid

[BaLiKfromUA]

@xibz @afrittoli this PR is ready for review, from my perspective. I've fixed all signing issues and last run of CI was green (+ I checked locally).

Thank you in advance for your review time :)

[Copilot]

Pull request overview

This PR extends the Core Events specification by adding a new queued predicate for the taskRun subject, including the associated JSON Schema and a conformance example, and updating the Core Events documentation accordingly (per issue #305).

Changes:

• Added a new JSON Schema for the taskRun.queued event.
• Added a taskRun.queued conformance example event payload.
• Updated core.md to list taskRun as supporting queued and to document the new event (and corrected taskName descriptions).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
schemas/taskrunqueued.json	Introduces the JSON Schema for the taskRun.queued event.
core.md	Documents the new taskRun.queued predicate/event and updates taskRun predicate listings.
conformance/taskrun_queued.json	Adds an example payload for taskRun.queued conformance.

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[afrittoli]

Thanks, this looks good!

[BaLiKfromUA]

@afrittoli thank you a lot for review! I don't have merge access so please merge this PR if we don't wait for other maintainers.

But I am not in rush obviously, just don't know what it the process of merging in this repo :)

[afrittoli]

@xibz @davidB if you're ok with this, we can squash-merge, unless @BaLiKfromUA prefers to squash and re-push.

[BaLiKfromUA]

I am okay with squash-merge from your side.

[xibz]

@afrittoli no objections from me.

Thanks for the PR @BaLiKfromUA!

LGTM