I18N: Ignore non-string values in the locale getters by sirreal · Pull Request #13335 · WordPress/wordpress-develop

sirreal · 2026-08-31T09:58:41Z

Prevent non-string locale values from causing a TypeError during just-in-time translation. Arrays can come from stored options, user meta, globals, filters or request parameters; the existing truthiness checks accept them.

Add is_string() checks to get_locale(), get_user_locale() and determine_locale(). sanitize_locale_name() returns an empty string for a non-string, so the sanitize_locale_name filter receives the documented type. Invalid values use the existing fallbacks: en_US for the site locale, get_locale() for the user or request locale, and the unfiltered locale for invalid filter results. Empty globals and empty locale or determine_locale filter results now use these fallbacks too. Locale string syntax is unchanged.

Writers are unchanged: wp_insert_user(), meta_input and direct metadata writes can still store non-strings, so the getters validate on read.

Adds regression tests for stored values, globals, filters and request parameters, including translation calls with array locales.

Trac ticket: https://core.trac.wordpress.org/ticket/66106

Use of AI Tools

AI assistance: Yes
Tools: Claude Code (Claude Opus 5, Claude Fable 5.1), Codex
Used for: Investigation, implementation, tests, review and description. Codex revised the description.

This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

`get_locale()`, `get_user_locale()` and `determine_locale()` are each documented to return a string, and each takes its value from a source that carries no type: the `WPLANG` option and site option, the `WPLANG` constant, the `$locale` and `$wp_local_package` globals, the `locale` user meta row, the `wp_lang` request parameter and cookie, and the `locale`, `option_WPLANG` and `determine_locale` filters. Only `empty()` and truthiness stood in the way, and a non-empty array passes both. A non-string locale reaches `WP_Textdomain_Registry::set()`, which uses it as an array key, so the first just-in-time translation for an unloaded text domain ends the request with "Cannot access offset of type array on array". On `wp-login.php` that needs no authentication: `sanitize_locale_name()` applies `preg_replace()`, which maps over an array subject and returns an array, so `?wp_lang[]=de_DE` carries one straight through. Add `is_string()` beside the non-empty checks that are already there, and fall back the way each function already falls back: to `en_US` for the site locale, to `get_locale()` for the user locale, and to the unfiltered value when a filter returns something else. Shape is left alone; only the type and emptiness are checked, so locales that work today keep working. Also ignore a non-string `locale` field in `wp_insert_user()`, the one core write path that stored it unchecked. That does not repair rows already in the database, which is why the read side is guarded too.

github-actions · 2026-08-31T10:01:53Z

Test using WordPress Playground

The changes in this pull request can previewed and tested using a WordPress Playground instance.

WordPress Playground is an experimental project that creates a full WordPress instance entirely within the browser.

Some things to be aware of

All changes will be lost when closing a tab with a Playground instance.
All changes will be lost when refreshing the page.
A fresh instance is created each time the link below is clicked.
Every time this pull request is updated, a new ZIP file containing all changes is created. If changes are not reflected in the Playground instance,
it's possible that the most recent build failed, or has not completed. Check the list of workflow runs to be sure.

For more details about these limitations and more, check out the Limitations page in the WordPress Playground documentation.

Test this pull request with WordPress Playground.

The single test named for `wp_insert_user()` only called `wp_update_user()`, so nothing exercised the field on user creation, which is the path the guard was added for. Split it in two: one test creates a user with a non-string `locale` field, the other updates one that already holds `de_DE`. The update case keeps its assertion that the row ends up empty, and its docblock now says so: a non-string does not leave the stored locale in place, it empties the row, which is the value the field takes when it is not passed at all.

The `@since` lines named only non-string values, but the guards also changed what an empty value does: on the `$locale` global short-circuit in `get_locale()`, and on the return of the `locale` and `determine_locale` filters, an empty value now falls back where it used to be returned. `wp_insert_user()` does not ignore a non-string `locale` field either. It stores an empty string, which for an update means the row is emptied rather than left alone. Also name the writers of the `$locale` global at the guard that reads it.

get_option() applies `option_{$option}` only when the option exists, and the test database has no `WPLANG` row, so the filter never ran and the test passed against unpatched source for all seven data sets. Write the row before adding the filter. The test now fails on trunk for six of the seven, the exception being the empty array, which `empty()` already caught.

Keep the one thing the reader cannot see from the code, where each value comes from, and cut the rest. Drop the `@since` lines. This fixes a fatal error, it does not change an API.

The getters now ignore non-string values, and other write paths such as meta_input and update_user_meta() store them unchanged. Validating one writer changes what wp_insert_user() stores for scalars without closing the gap.

@return

Annotate the tests added for the locale getter type checks: void on the test methods and the raw option row helper, array on the data providers, and array shapes in place of array[] in their @return lines.

github-actions · 2026-09-14T16:02:35Z

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 jonsurrell.

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

@ticket

Add @ticket 66106 to the 16 test methods this change adds. The data providers and the raw option row helper carry no ticket reference.

State what the tests cover in terms of types and the registry, without spelling out a request that ends in a fatal error on a released site.

…ring. determine_locale() passed request values to sanitize_locale_name() before its own type check. preg_replace() maps over an array, so the `sanitize_locale_name` filter received arrays in both arguments that it documents as strings.

One test per guarded source: the option, the `$locale` global, the `locale` filter, user meta, the `wp_lang` request parameter and the `determine_locale` filter, plus the translation call that threw the TypeError. Drop the data providers and the duplicate string-type assertion.

sirreal · 2026-09-14T16:41:49Z

@josephscott This is ready for review if you'd like to take a look.

westonruter · 2026-09-15T19:24:35Z

+	 *
+	 * @ticket 66106
+	 */
+	public function test_sanitize_locale_name_returns_empty_string_for_a_non_string() {


Since the other test methods have void:

Suggested change

public function test_sanitize_locale_name_returns_empty_string_for_a_non_string() {

public function test_sanitize_locale_name_returns_empty_string_for_a_non_string(): void {

westonruter · 2026-09-15T19:29:24Z

+	 *
+	 * @ticket 66106
+	 *
+	 * @group ms-excluded


The methods could add global docs:

Suggested change

* @group ms-excluded

* @group ms-excluded

*

* @global wpdb $wpdb WordPress database abstraction object.

* @global string $locale The current locale.

westonruter · 2026-09-15T19:30:21Z

+	 * @ticket 66106
+	 */
+	public function test_sanitize_locale_name_returns_empty_string_for_a_non_string() {
+		$this->assertSame( '', sanitize_locale_name( array( 'de_DE' ) ) );


Suggested change

$this->assertSame( '', sanitize_locale_name( array( 'de_DE' ) ) );

$this->assertSame( '', sanitize_locale_name( array( 'de_DE' ) ) ); // @phpstan-ignore argument.type (Passing an array is intentional here.)

westonruter · 2026-09-15T19:34:19Z

+		wp_cache_flush();
+
+		$found  = get_locale();
+		$locale = $old_locale;


This should be done in tear_down. (And in the other test methods too.)

westonruter · 2026-09-15T19:35:11Z

+		$old_locale = $locale;
+		$locale     = null;


This should be done in set_up. (And in the other test methods too.)

sirreal added 8 commits September 14, 2026 14:52

Merge branch 'trunk' into fix/locale-getter-type-validation

3ec6881

Merge trunk into fix/locale-getter-type-validation.

b4cc5f8

Docs: Trim the comments on the locale guards.

d6b2ae6

Keep the one thing the reader cannot see from the code, where each value comes from, and cut the rest. Drop the `@since` lines. This fixes a fatal error, it does not change an API.

Users: Drop the wp_insert_user() locale type check.

9da8fc8

The getters now ignore non-string values, and other write paths such as meta_input and update_user_meta() store them unchanged. Validating one writer changes what wp_insert_user() stores for scalars without closing the gap.

Tests: Add return types to the locale getter type tests.

cae7c02

Annotate the tests added for the locale getter type checks: void on the test methods and the raw option row helper, array on the data providers, and array shapes in place of array[] in their @return lines.

sirreal marked this pull request as ready for review September 14, 2026 16:02

sirreal added 2 commits September 14, 2026 20:04

Tests: Reference the ticket from the locale getter type tests.

ce9a317

Add @ticket 66106 to the 16 test methods this change adds. The data providers and the raw option row helper carry no ticket reference.

Tests: Describe the locale type failure without the request recipe.

50ce952

State what the tests cover in terms of types and the registry, without spelling out a request that ends in a fatal error on a released site.

sirreal marked this pull request as draft September 14, 2026 16:09

sirreal added 2 commits September 14, 2026 20:14

sirreal marked this pull request as ready for review September 14, 2026 16:40

westonruter requested changes Sep 15, 2026

View reviewed changes

Navigation Menu

Uh oh!

I18N: Ignore non-string values in the locale getters - #13335

I18N: Ignore non-string values in the locale getters#13335
sirreal wants to merge 13 commits into
WordPress:trunkfrom
sirreal:fix/locale-getter-type-validation

sirreal commented Aug 31, 2026 •

edited

Loading

Uh oh!

github-actions Bot commented Aug 31, 2026

Uh oh!

github-actions Bot commented Sep 14, 2026

Uh oh!

sirreal commented Sep 14, 2026

Uh oh!

westonruter Sep 15, 2026

Uh oh!

westonruter Sep 15, 2026

Uh oh!

westonruter Sep 15, 2026

Uh oh!

westonruter Sep 15, 2026

Uh oh!

westonruter Sep 15, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

	public function test_sanitize_locale_name_returns_empty_string_for_a_non_string() {
	public function test_sanitize_locale_name_returns_empty_string_for_a_non_string(): void {

	$this->assertSame( '', sanitize_locale_name( array( 'de_DE' ) ) );
	$this->assertSame( '', sanitize_locale_name( array( 'de_DE' ) ) ); // @phpstan-ignore argument.type (Passing an array is intentional here.)

Uh oh!

Conversation

sirreal commented Aug 31, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Use of AI Tools

Uh oh!

github-actions Bot commented Aug 31, 2026

Test using WordPress Playground

Some things to be aware of

Uh oh!

github-actions Bot commented Sep 14, 2026

Uh oh!

sirreal commented Sep 14, 2026

Uh oh!

westonruter Sep 15, 2026

Choose a reason for hiding this comment

Uh oh!

westonruter Sep 15, 2026

Choose a reason for hiding this comment

Uh oh!

westonruter Sep 15, 2026

Choose a reason for hiding this comment

Uh oh!

westonruter Sep 15, 2026

Choose a reason for hiding this comment

Uh oh!

westonruter Sep 15, 2026

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

sirreal commented Aug 31, 2026 •

edited

Loading