Add a file existence check in class-wp-theme-json-resolver to avoid…

[pbearne]

… potential errors.

Trac ticket: https://core.trac.wordpress.org/ticket/64620

[github-actions]

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[github-actions]

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[westonruter]

@pbearne It's still not clear how to reproduce this issue. I wonder if wrapping the code in an is_readable() will just make it harder to debug. Should there be an else statement to say the expected file is missing? Again, having a way to reproduce this would be helpful, and thus could be added as a test.

[pbearne]

@westonruter what would you like in the else
an error
an empty array is already returned as default

[Copilot]

Pull request overview

This PR adjusts WP_Theme_JSON_Resolver::read_json_file() to avoid calling wp_json_file_decode() when the passed path is not readable, preventing avoidable errors/warnings when theme.json (or similar JSON files) are missing or inaccessible.

Changes:

• Add a readability check before decoding JSON files in WP_Theme_JSON_Resolver::read_json_file().
• Preserve existing caching behavior for successfully decoded theme.json-shaped arrays.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/wp-includes/class-wp-theme-json-resolver.php:114

• is_readable() is true for directories, which would still allow wp_json_file_decode() to run. That function calls json_decode( file_get_contents( $filename ) ...); if file_get_contents() returns false (e.g., path is a directory), PHP 8+ can throw a TypeError because json_decode() requires a string. Consider requiring a regular file as well as readability before decoding.

			if ( is_readable( $file_path ) ) {
				$decoded_file = wp_json_file_decode( $file_path, array( 'associative' => true ) );
				if ( is_array( $decoded_file ) ) {
					static::$theme_json_file_cache[ $file_path ] = $decoded_file;
					return static::$theme_json_file_cache[ $file_path ];
				}

[t-hamano]

@pbearne Can you address the feedback from Copilot? Both seem like reasonable points to me.