Script Loader: Guard compression_test() with manage_options check

[irozum]

compression_test() is called from wp-admin/admin-footer.php for every user who can access wp-admin, whenever the can_compress_scripts option is unset — not only administrators. It outputs a <script> block that fires AJAX requests to the wp-compression-test action, but that AJAX handler (wp_ajax_wp_compression_test()) requires the manage_options capability, so non-admin users (e.g. Editors) get -1 responses and can never actually resolve the test. This also contradicts the function's own docblock, which states it "Has no effect when the current user is not an administrator."

This PR adds a current_user_can( 'manage_options' ) check at the top of compression_test() so it returns early — and outputs nothing — for users who can't act on the result, matching the documented behavior. Administrators are unaffected.

Trac ticket: https://core.trac.wordpress.org/ticket/65750

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Claude Sonnet 5
Used for: Implementation, tests, and PR description. Reviewed by Igor Rozum.

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[Copilot]

Pull request overview

This PR updates the Script Loader compression test so it only outputs its inline <script> block for users who can actually complete the related AJAX flow (i.e., users with the manage_options capability), aligning runtime behavior with the existing docblock and the capability check already enforced by the wp_ajax_wp_compression_test() handler.

Changes:

• Add an early current_user_can( 'manage_options' ) guard in compression_test() to prevent output for non-privileged wp-admin users.
• Add PHPUnit coverage to verify compression_test() outputs nothing for a user without manage_options, and still outputs the test script for a user with it.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/wp-admin/includes/template.php	Adds a manage_options capability guard to prevent emitting the compression-test inline script for non-admin-capable users.
tests/phpunit/tests/admin/includesTemplate.php	Adds tests asserting compression_test() output is empty for an Editor and contains the test script for an Administrator.

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[github-actions]

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[szepeviktor]

@irozum Maybe you should add your modification at the root:

wordpress-develop/src/wp-admin/admin-footer.php

Lines 107 to 112 in d7de266

	// get_site_option() won't exist when auto upgrading from <= 2.7.
	if ( function_exists( 'get_site_option' )
	&& false === get_site_option( 'can_compress_scripts' )
	) {
	compression_test();
	}

[westonruter]

Suggested change

	ob_start();
	compression_test();
	$output = ob_get_clean();
	$output = get_echo( 'compression_test' );

[westonruter]

Suggested change

	ob_start();
	compression_test();
	$output = ob_get_clean();
	$output = get_echo( 'compression_test' );