Changeset 59070

Timestamp:

09/19/2024 08:20:30 PM (3 months ago)

Author:

hellofromTonya

Message:

External Libraries: Skip instanceof check when null in Text_Diff::_check().

On the first foreach loop in Text_Diff::_check(), $prevtype is null. As instanceof` requires the class name term to be an object or string, a fatal error is thrown:

Fatal error: Uncaught Error: Class name must be a valid object or a string on line 279

This change:

• Adds a simple test for the Text_Diff::_check() method, which is how the bug was discovered as the test could never pass with the code as-is.

• Adds a defensive guard to protect against the fatal. It checks if $prevtype is not null as a pre-condition to for checking the instance. This bugfix also resolves the failing test.

Follow-up to [49194], [7747].

Props jrf, hellofromTonya.
See #62083.

Location:

trunk

Files:

• src/wp-includes/Text/Diff.php (modified) (1 diff)
• tests/phpunit/tests/diff/Text_Diff_Check_Test.php (added)

trunk/src/wp-includes/Text/Diff.php

@@ -277 +277 @@
         $prevtype = null;
         foreach ($this->_edits as $edit) {
-            if ($edit instanceof $prevtype) {
+            if ($prevtype !== null && $edit instanceof $prevtype) {
                 trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
             }