Changeset 56681 for trunk/src/wp-includes/option.php

Timestamp:

09/25/2023 04:23:52 PM (16 months ago)

Author:

flixos90

Message:

Options, Meta APIs: Improve logic to avoid unnecessary database writes in update_option().

Prior to this change, a strict comparison between the old and new database value could lead to a false negative, since database values are generally stored as strings. For example, passing an integer to update_option() would almost always result in an update given any existing database value for that option would be that number cast to a string.

This changeset adjusts the logic to perform an intentional "loose-y" comparison by casting the values to strings. Extensive coverage previously added in [56648] provides additional confidence that this does not introduce any backward compatibility issues.

Props mukesh27, costdev, spacedmonkey, joemcgill, flixos90, nacin, atimmer, duck_, boonebgorges.
Fixes #22192.

File:

• trunk/src/wp-includes/option.php (modified) (2 diffs)

trunk/src/wp-includes/option.php

@@ -777 +777 @@
     $value = apply_filters( 'pre_update_option', $value, $option, $old_value );
 
+    /** This filter is documented in wp-includes/option.php */
+    $default_value = apply_filters( "default_option_{$option}", false, $option, false );
+
     /*
      * If the new and old values are the same, no need to update.
      *
-     * Unserialized values will be adequate in most cases. If the unserialized
-     * data differs, the (maybe) serialized data is checked to avoid
-     * unnecessary database calls for otherwise identical object instances.
-     *
-     * See https://core.trac.wordpress.org/ticket/38903
-     */
-    if ( $value === $old_value || maybe_serialize( $value ) === maybe_serialize( $old_value ) ) {
+     * An exception applies when no value is set in the database, i.e. the old value is the default.
+     * In that case, the new value should always be added as it may be intentional to store it rather than relying on the default.
+     *
+     * See https://core.trac.wordpress.org/ticket/38903 and https://core.trac.wordpress.org/ticket/22192.
+     */
+    if ( $old_value !== $default_value && _is_equal_database_value( $old_value, $value ) ) {
         return false;
     }
 
-    /** This filter is documented in wp-includes/option.php */
-    if ( apply_filters( "default_option_{$option}", false, $option, false ) === $old_value ) {
+    if ( $old_value === $default_value ) {
+
         // Default setting for new options is 'yes'.
         if ( null === $autoload ) {
@@ -2888 +2890 @@
     return $registered[ $option ]['default'];
 }
+
+/**
+ * Determines whether two values will be equal when stored in the database.
+ *
+ * @since 6.4.0
+ * @access private
+ *
+ * @param mixed $old_value The old value to compare.
+ * @param mixed $new_value The new value to compare.
+ * @return bool True if the values are equal, false otherwise.
+ */
+function _is_equal_database_value( $old_value, $new_value ) {
+    $values = array(
+        'old' => $old_value,
+        'new' => $new_value,
+    );
+
+    foreach ( $values as $_key => &$_value ) {
+        // Cast scalars or null to a string so type discrepancies don't result in cache misses.
+        if ( null === $_value || is_scalar( $_value ) ) {
+            $_value = (string) $_value;
+        }
+    }
+
+    if ( $values['old'] === $values['new'] ) {
+        return true;
+    }
+
+    /*
+     * Unserialized values will be adequate in most cases. If the unserialized
+     * data differs, the (maybe) serialized data is checked to avoid
+     * unnecessary database calls for otherwise identical object instances.
+     *
+     * See https://core.trac.wordpress.org/ticket/38903
+     */
+    return maybe_serialize( $old_value ) === maybe_serialize( $new_value );
+}