Fix: #57469 fatal error when a sidebar widgets set to null #9603

DarkMatter-999 · 2025-08-26T13:01:12Z

Trac ticket: https://core.trac.wordpress.org/ticket/57469

The PR ensures that any NULL values in the sidebars_widgets array are replaced with empty arrays during widget retrieval and mapping.

This is needed as PHP 8.x introduces stricter type and warning behaviors that can break assumptions made in earlier versions.

Code used to testing:

DELETE FROM `wp_options` WHERE `option_name` = 'sidebars_widgets';
INSERT INTO `wp_options` (`option_name`, `option_value`, `autoload`) VALUES ('sidebars_widgets','a:2:{s:19:"wp_inactive_widgets";N;s:9:"sidebar-1";N;}','yes');

Before:

sidebar-null-values-before.mov

After:

sidebar-null-values-after.mov

github-actions · 2025-08-26T13:20:28Z

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github-actions · 2025-08-27T09:25:15Z

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Core Committers: Use this line as a base for the props when committing in SVN:

Props lakshyajeet, westonruter, mindctrl.

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

…` and `wp_map_sidebars_widgets()`

mindctrl · 2025-09-08T19:22:23Z

@DarkMatter-999 thanks for adding phpunit tests.

Here's my test report for this PR:

Test Report

Description

This report validates whether the indicated patch works as expected.

Patch tested: #9603

Environment

WordPress: 6.9-alpha-60093-src
PHP: 8.2.29
Server: nginx/1.29.0
Database: mysqli (Server: 8.4.6 / Client: mysqlnd 8.2.29)
Browser: Chrome 140.0.0.0
OS: macOS
Theme: Twenty Twenty-Five 1.3
MU Plugins:
- phpmailer.php
Plugins:
- Test Reports 1.2.0

Actual Results

✅ Issue resolved with patch.

Additional Notes

Without this patch, once the fatal error happens, the site is inoperable until a manual fix is applied.
Since it's unclear how the sidebar widgets get set to null in some cases, I manually created wp_options.sidebars_widgets with a sidebar containing a null value using the MySQL commands in the description above.

Delete existing config

mysql> DELETE FROM `wp_options` WHERE `option_name` = 'sidebars_widgets';
Query OK, 1 row affected (0.00 sec)

Insert config with null values

mysql> INSERT INTO `wp_options` (`option_name`, `option_value`, `autoload`) VALUES ('sidebars_widgets','a:2:{s:19:"wp_inactive_widgets";N;s:9:"sidebar-1";N;}','yes');
Query OK, 1 row affected (0.00 sec)

Get config to confirm new values

mysql> select * from wp_options where option_name = 'sidebars_widgets';
+-----------+------------------+-------------------------------------------------------+----------+
| option_id | option_name      | option_value                                          | autoload |
+-----------+------------------+-------------------------------------------------------+----------+
|       175 | sidebars_widgets | a:2:{s:19:"wp_inactive_widgets";N;s:9:"sidebar-1";N;} | yes      |
+-----------+------------------+-------------------------------------------------------+----------+
1 row in set (0.00 sec)

Get config after switching themes in wp-admin

mysql> select * from wp_options where option_name = 'sidebars_widgets';
+-----------+------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+
| option_id | option_name      | option_value                                                                                                                                                                                                                                                             | autoload |
+-----------+------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+
|       175 | sidebars_widgets | a:7:{s:19:"wp_inactive_widgets";a:5:{i:0;s:7:"block-2";i:1;s:7:"block-3";i:2;s:7:"block-4";i:3;s:7:"block-5";i:4;s:7:"block-6";}s:9:"sidebar-1";a:0:{}s:9:"sidebar-2";a:0:{}s:9:"sidebar-3";a:0:{}s:9:"sidebar-4";a:0:{}s:9:"sidebar-5";a:0:{}s:13:"array_version";i:3;} | yes      |
+-----------+------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+
1 row in set (0.00 sec)

mysql>

westonruter · 2025-09-08T21:59:45Z

src/wp-includes/widgets.php


+	// Replace null values inside the array with an empty array.
+	foreach ( $sidebars_widgets as $key => $value ) {
+		if ( null === $value ) {


What if it was set to something other than an array or null, like a string, boolean, integer, or object? Wouldn't this be more appropriate:

Suggested change

if ( null === $value ) {

if ( ! is_array( $value ) ) {

moving forward with this approach

westonruter · 2025-09-08T22:00:54Z

src/wp-includes/widgets.php


+		// Replace null values inside the array with an empty array.
+		foreach ( $new_sidebars_widgets as $key => $value ) {
+			if ( null === $value ) {


Suggested change

if ( null === $value ) {

if ( ! is_array( $value ) ) {

westonruter · 2025-09-08T22:05:12Z

src/wp-includes/widgets.php

+	// Replace null values inside the array with an empty array.
+	foreach ( $sidebars_widgets as $key => $value ) {
+		if ( null === $value ) {
+			$sidebars_widgets[ $key ] = array();
+		}
+	}


Alternatively:

Suggested change

// Replace null values inside the array with an empty array.

foreach ( $sidebars_widgets as $key => $value ) {

if ( null === $value ) {

$sidebars_widgets[ $key ] = array();

}

}

$sidebars_widgets = array_filter( $sidebars_widgets, 'is_array' );

I think checking for is_array will be a better solution and is a drop in replacement because it preserves sidebar keys and guarantees any downstream operations receive arrays, this is consistent with how older PHP version like 7.4 handle array_merge and array_search.

Using array_filter($sidebars_widgets, 'is_array') will remove entries that are not arrays, which can drop keys and change control flow in the downstream code that expects those keys to exist.

westonruter · 2025-09-08T22:06:04Z

src/wp-includes/widgets.php

+		// Replace null values inside the array with an empty array.
+		foreach ( $new_sidebars_widgets as $key => $value ) {
+			if ( null === $value ) {
+				$new_sidebars_widgets[ $key ] = array();
+			}
+		}


Alternatively:

Suggested change

// Replace null values inside the array with an empty array.

foreach ( $new_sidebars_widgets as $key => $value ) {

if ( null === $value ) {

$new_sidebars_widgets[ $key ] = array();

}

}

$new_sidebars_widgets = array_filter( $new_sidebars_widgets, 'is_array' );

westonruter

This looks good. Just a minor suggestion to merge a couple assertions.

tests/phpunit/tests/widgets.php

github-actions · 2025-09-12T18:04:15Z

A commit was made that fixes the Trac ticket referenced in the description of this pull request.

SVN changeset: 60732
GitHub commit: c683208

This PR will be closed, but please confirm the accuracy of this and reopen if there is more work to be done.

fix: replace null sidebar widget entries with empty arrays

474077d

docs: improve clarity of inline comments

fff3b1e

DarkMatter-999 marked this pull request as ready for review August 27, 2025 09:25

test: add tests for null sidebar normalization in `retrieve_widgets()…

e5d56b5

…` and `wp_map_sidebars_widgets()`

westonruter requested changes Sep 8, 2025

View reviewed changes

DarkMatter-999 added 2 commits September 9, 2025 11:43

fix: add check for whether the value is an array

1c298fd

docs: update comments to reflect changes

ce06687

DarkMatter-999 requested a review from westonruter September 11, 2025 10:37

westonruter approved these changes Sep 12, 2025

View reviewed changes

tests/phpunit/tests/widgets.php Outdated Show resolved Hide resolved

tests/phpunit/tests/widgets.php Outdated Show resolved Hide resolved

test: simplified widget tests

484c479

github-actions bot closed this Sep 12, 2025

Fix: #57469 fatal error when a sidebar widgets set to null #9603

Fix: #57469 fatal error when a sidebar widgets set to null #9603

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DarkMatter-999 commented Aug 26, 2025

Before:

After:

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github-actions bot commented Aug 26, 2025

Test using WordPress Playground

Some things to be aware of

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github-actions bot commented Aug 27, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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mindctrl commented Sep 8, 2025

Test Report

Description

Environment

Actual Results

Additional Notes

Delete existing config

Insert config with null values

Get config to confirm new values

Get config after switching themes in wp-admin

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github-actions bot commented Aug 27, 2025 •

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