Run composer compat as a part of grunt (precommit|prerelease)

[KarunyaChavan]

This PR wires composer compat into the Grunt build pipeline so that potential PHP compatibility regressions are caught automatically before a commit or release.

Trac ticket: https://core.trac.wordpress.org/ticket/50393

What this changes

Gruntfile.js

• Registers a new compat:php Grunt task that invokes composer compat (i.e. phpcs --standard=phpcompat.xml.dist) against the set of changed PHP files, consistent with how the existing lint:php and format:php tasks are structured.
• Adds compat:php to the precommit:php task sequence (between phpstan and phpunit), so it runs automatically during both grunt precommit (when .php files are staged) and grunt prerelease (which already includes precommit:php).
• Fixes a silent array-mutation bug in format:php and lint:php where args.unshift() was modifying the shared changedFiles.php array reference in place. Both tasks now call .slice() to operate on a copy, preventing the composer subcommand name from being prepended to the shared array between task runs.

Use of AI Tools

AI assistance: Yes
Model(s): GPT-5-mini
Used for: Surfacing the changedFiles.php mutation bug and verifying optimality of patch.

[github-actions]

Hi @KarunyaChavan! 👋

Thank you for your contribution to WordPress! 💖

It looks like this is your first pull request to wordpress-develop. Here are a few things to be aware of that may help you out!

No one monitors this repository for new pull requests. Pull requests must be attached to a Trac ticket to be considered for inclusion in WordPress Core. To attach a pull request to a Trac ticket, please include the ticket's full URL in your pull request description.

Pull requests are never merged on GitHub. The WordPress codebase continues to be managed through the SVN repository that this GitHub repository mirrors. Please feel free to open pull requests to work on any contribution you are making.

More information about how GitHub pull requests can be used to contribute to WordPress can be found in the Core Handbook.

Please include automated tests. Including tests in your pull request is one way to help your patch be considered faster. To learn about WordPress' test suites, visit the Automated Testing page in the handbook.

If you have not had a chance, please review the Contribute with Code page in the WordPress Core Handbook.

The Developer Hub also documents the various coding standards that are followed:

• PHP Coding Standards
• CSS Coding Standards
• HTML Coding Standards
• JavaScript Coding Standards
• Accessibility Coding Standards
• Inline Documentation Standards

Thank you,
The WordPress Project

[github-actions]

Test using WordPress Playground

The changes in this pull request can previewed and tested using a WordPress Playground instance.

WordPress Playground is an experimental project that creates a full WordPress instance entirely within the browser.

Some things to be aware of

• All changes will be lost when closing a tab with a Playground instance.
• All changes will be lost when refreshing the page.
• A fresh instance is created each time the link below is clicked.
• Every time this pull request is updated, a new ZIP file containing all changes is created. If changes are not reflected in the Playground instance,
  it's possible that the most recent build failed, or has not completed. Check the list of workflow runs to be sure.

For more details about these limitations and more, check out the Limitations page in the WordPress Playground documentation.

Test this pull request with WordPress Playground.

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Core Committers: Use this line as a base for the props when committing in SVN:

Props karunyachavan84.

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.