Rewrite Rules: Require a path-segment boundary when stripping the home path in WP::parse_request()

[irozum]

WP::parse_request() strips the site's home path off the front of PATH_INFO/REQUEST_URI/PHP_SELF using a regex built with sprintf( '|^%s|i', preg_quote( $home_path, '|' ) ). Because this only anchors on the start of the string and never checks what comes right after the home path, it matches any path that merely begins with the same characters as the home path, not just paths that are actually nested under it.

For a site installed in a subdirectory named wp, a request for wp-json/wc/v1/products (a REST API route) gets the literal substring wp stripped off the front, leaving the mangled path -json/wc/v1/products — breaking REST API routing on such installs. The same root cause affects any endpoint whose name happens to share a prefix with the install's subdirectory (e.g. a sitemap.xml request on a site installed under /site).

This changes the regex to require a / or end-of-string right after the home path (!^%s(?:/|$)!i) before stripping it, so a bare prefix match like wp-json is left alone, while a real subdirectory match like wp/wp-json/... still has wp/ stripped correctly.

Adds a regression test, Tests_WP_ParseRequest::test_pathinfo_prefix_matching_home_path_is_not_stripped, which fails on trunk and passes with this fix.

Trac ticket: https://core.trac.wordpress.org/ticket/40339

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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