Fix server processing of wp-context getting out of sync

[luisherranz]

What?

Fix a problem where the internal stack of contexts could get out of sync when the JSON is not valid during the server processing of wp-context.

Why?

As spotted by @DAreRodz here, the internal stack of contexts can get out of sync when a call to set_context fails.

For context, the "Fatal error" that can be seen in #54816 (comment) is caused by a problem insidegutenberg_interactivity_process_wp_context implementation, which is calling $context->rewind_context() even when no context where added on a potential failure. That could empty the context stack and make subsequent $context->set_context( $new_context ) calls fail.

How?

Make sure that we're always adding a new array to the stack, even if the JSON is not valid.

Testing Instructions

This is covered by a unit test, but if you want to test it out:

• Add an interactive block.
• Add a div with valid JSON in a wp-context directive.
• Add nested divs inside with wp-context and invalid JSONs.
• Check that it doesn't do a fatal error and that the initial context is still valid.

[github-actions]

This pull request has changed or added PHP files. Please confirm whether these changes need to be synced to WordPress Core, and therefore featured in the next release of WordPress.

If so, it is recommended to create a new Trac ticket and submit a pull request to the WordPress Core Github repository soon after this pull request is merged.

If you're unsure, you can always ask for help in the #core-editor channel in WordPress Slack.

Thank you! ❤️

View changed files

❔ lib/experimental/interactivity-api/class-wp-directive-context.php
❔ lib/experimental/interactivity-api/directives/wp-context.php
❔ phpunit/experimental/interactivity-api/directives/wp-context-test.php

[github-actions]

Flaky tests detected in f341fc1.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/6558724095
📝 Reported issues:

• [Flaky Test] should partially select with shift + click (@webkit) #53524 in /test/e2e/specs/editor/various/multi-block-selection.spec.js

[DAreRodz]

The code looks good to me. Approved!

PS: There's a thing that worries me: this is supposed to fail only when the content of wp-context is not valid. Are we generating an invalid context somewhere, or could it be a different issue this time? 🤔

[luisherranz]

For now, let's cover invalid contexts. If more problems arise, we'll check them out 🙂

Thanks for the quick review, David! 🎉

[mikachan]

👋 Hey! Checking if this PR should be included in 6.4 - if so, we should add the Backport to WP Beta/RC label. Thanks!

[luisherranz]

Hey @mikachan. No, this part is still experimental and it's not included in the 6.4 release.