Fix: cast $blog_id to int in wp_cache_clear_cache() to prevent crash on non-multisite installs

[DeveloperBatuhanALGUL]

Problem

When a third-party theme or plugin calls wp_cache_clear_cache('all', false) with a non-integer $blog_id, the function passes that value directly to get_supercache_dir(), which internally calls get_blog_option() — a multisite-only function. On non-multisite installs, this causes a fatal error.

Fixes #1019

Fix

Cast $blog_id to int at the top of the function. This ensures any non-integer value (e.g. 'all', false) is normalized to 0, which correctly triggers the single-site cache clearing path.

Testing

1. On a non-multisite WordPress install, call wp_cache_clear_cache('all', false)
2. Confirm no fatal error occurs and cache is cleared correctly

[donnchawp]

This review was generated by AI.

The (int) $blog_id cast is correct and resolves #1019: (int) 'all' and (int) false both normalize to 0, routing to the single-site path. Normalizing the parameter to the type the function assumes is the right data-level fix. That one line should be the entire PR.

The other four changes (@fclose( $fr ) → if ( $fr ) { fclose( $fr ); }) are unrelated to #1019 and should be dropped:

1. Out of scope. The PR title, body, and linked issue describe only the cast. The fclose edits in wp_cache_get_ob() / wp_cache_shutdown_callback() are undocumented and touch a different code path.

2. Two are dead code. At lines ~2511 and ~2965 the new if ( $fr ) { fclose( $fr ); } sits inside an existing if ( $fr ) { block — the guard can never be false. Revert these to bare fclose( $fr );.

3. Inconsistent error handling. In the ! $gz branch a guarded close now sits beside @fclose( $fr2 ) and @unlink( ... ), so the error path is no longer uniform. Either leave the block's existing @ style untouched, or change it consistently — not half.

Please resubmit with only the $blog_id cast.

Minor (no change required): global declarations conventionally precede statements, but order doesn't affect global semantics here.

[donnchawp]

This comment was generated by AI.

For visibility: to unblock a release, the two genuinely-needed fixes in this PR have been split into focused PRs:

• Cast $blog_id to int in wp_cache_clear_cache() #1054 — the (int) $blog_id cast (fixes improper handling of arguments in wp_cache_clear_cache function / was: WP Super Cache using multsite function get_blog_option when doing bulk-updates for plugins on non-multisite #1019, this PR's stated goal).
• Guard fclose() against false stream in supercache-only mode #1053 — the fclose( $fr ) guards in the error branches, which fix a separate critical bug: @fclose( false ) fatals on PHP 8+ (@ doesn't suppress TypeError). That's issue WP Super Cache fclose(): Argument #1 ($stream) must be of type resource, false given #1016.

So this PR actually addressed two real issues. The remaining two changes here (the fclose( $fr ) guards at the call sites that are already inside if ( $fr ) blocks) are redundant and were the basis of the earlier change request.

No action needed on your side — once #1053 and #1054 land, this PR can be closed as superseded. Thanks for surfacing both bugs.