Utils: Preserve omitted ability input

[jorgefilipecosta]

What?

• Preserves omitted runAbility() input as undefined instead of normalizing it to null.
• Omits REST fallback input payloads when the caller does not provide input.
• Keeps explicitly provided empty-object input as request input.

Why?

Some abilities use an object schema with a default empty object for empty collection/query mode. Passing null prevents the abilities client from applying that schema default and can make runAbility( 'core/users' ) fail where executeAbility( 'core/users' ) succeeds.

Core users is at #774.

How?

• Passes the optional runAbility() input argument through to the client abilities API without coercing omitted input to null.
• Builds REST fallback requests without a data.input payload when input is omitted.
• Preserves explicitly provided input values, including {}, when building REST fallback requests.

Use of AI Tools

AI assistance: Yes
Tool(s): Codex
Model(s): GPT-5
Used for: Implementation assistance, manual test planning, and PR description updates. Final changes were reviewed and verified locally.

Testing Instructions

Manual testing:

1. Use the Playground preview or a local environment with this PR and the core/users ability from Add core/read-users ability #774 available.
2. Open a WordPress admin page where the abilities client modules are loaded, such as the post editor after enabling one AI experiment.
3. In the browser console, run const { ready } = await import( '@wordpress/core-abilities' ); await ready; const { executeAbility } = await import( '@wordpress/abilities' ); await executeAbility( 'core/users' );.
4. Confirm the call succeeds and returns the users result without passing an input argument.
5. In the same browser console, run await wp.apiFetch( { path: '/wp-abilities/v1/abilities/core/users/run', method: 'POST' } );.
6. Confirm the REST fallback shape with no data.input also succeeds.
7. Run await wp.apiFetch( { path: '/wp-abilities/v1/abilities/core/users/run', method: 'POST', data: { input: {} } } );.
8. Confirm the explicit empty-object input still succeeds, verifying that omitted input and {} remain distinct.

Automated testing:

• npm run lint:js -- src/utils/run-ability.ts
• npm run typecheck

Screenshots or screencast

Not applicable; this is a utility behavior change without UI changes.

Changelog Entry

Fixed - Preserve omitted runAbility() input so ability schema defaults can apply when abilities are invoked without input.

[github-actions]

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Co-authored-by: jorgefilipecosta <jorgefilipecosta@git.wordpress.org>
Co-authored-by: dkotter <dkotter@git.wordpress.org>
Co-authored-by: gziolo <gziolo@git.wordpress.org>

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[github-actions]

✅ WordPress Plugin Check Report

✅ Status: Passed

📊 Report

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.48%. Comparing base (ea79289) to head (8d34d98).
⚠️ Report is 3 commits behind head on develop.

Additional details and impacted files

@@            Coverage Diff             @@
##             develop     #775   +/-   ##
==========================================
  Coverage      76.48%   76.48%           
  Complexity      1869     1869           
==========================================
  Files             89       89           
  Lines           7990     7990           
==========================================
  Hits            6111     6111           
  Misses          1879     1879           

Flag	Coverage Δ
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[gziolo]

Approved. Verified locally: install, build, tests, lint, and typecheck all pass. Nice, focused fix.

One small follow-up (not blocking): the GET/DELETE path has no test yet, and an explicit null is treated differently there (no input) than in POST (input: null). Worth a quick test and a decision on that case later.

[dkotter]

Would be great if we can ensure the PR template is followed here. Noticing the Use of AI Tools and Changelog Entry sections aren't provided right now and the Testing Instructions section just includes automated test steps whereas we want manual test steps there

[jorgefilipecosta]

Would be great if we can ensure the PR template is followed here. Noticing the Use of AI Tools and Changelog Entry sections aren't provided right now and the Testing Instructions section just includes automated test steps whereas we want manual test steps there

The description was updated 👍