I18N: Read the revision date key that GlotPress writes into .l10n.php files.

wp_get_l10n_php_file_data() maps `PO-Revision-Date` onto `po-revision-date`,
but GlotPress writes that value under `translation-revision-date`. The key core
looks for is absent from every language pack currently served, so the function
returns an empty revision date.

The name changed upstream. The `de_CH.l10n.php` fixture already in core reports
`GlotPress/4.0.0-beta.2` and uses `po-revision-date`, while packs generated by
`GlotPress/4.0.3` use `translation-revision-date`. The mapping was correct when
the function was added in 6.6 and stopped matching later. `Project-Id-Version`
and `X-Generator` still resolve, which is why nothing looked broken.

This matters because wp_get_installed_translations() falls back to this reader
when a translation has no sibling `.po` file, and the result is sent to
api.wordpress.org to decide which language packs are stale. An empty revision
date means an installed, current pack is offered again on every check.

Accept both spellings, preferring the current one, so files written before and
after the rename resolve.

`POT-Creation-Date` maps to `pot-creation-date`, which appears in neither
format, and is left alone rather than guessed at.

The existing coverage did not catch this because the only `.l10n.php` fixture it
asserts against predates the rename. Add a fixture in the current format and a
test that fails on trunk with an empty string.

Props bejignesh.
Fixes #65809.

Author: jigneshbhavani

src/wp-includes/l10n.php

@@ -1682,11 +1682,18 @@ function wp_get_l10n_php_file_data( $php_file ) {
 	$data = (array) include $php_file;
 
 	unset( $data['messages'] );
+
+	/*
+	 * Each PO header maps to the keys a `.l10n.php` file may store it under, in
+	 * order of preference. GlotPress writes the revision date as
+	 * 'translation-revision-date'; files generated before that renaming use
+	 * 'po-revision-date', so both are accepted.
+	 */
 	$headers = array(
-		'POT-Creation-Date'  => 'pot-creation-date',
-		'PO-Revision-Date'   => 'po-revision-date',
-		'Project-Id-Version' => 'project-id-version',
-		'X-Generator'        => 'x-generator',
+		'POT-Creation-Date'  => array( 'pot-creation-date' ),
+		'PO-Revision-Date'   => array( 'translation-revision-date', 'po-revision-date' ),
+		'Project-Id-Version' => array( 'project-id-version' ),
+		'X-Generator'        => array( 'x-generator' ),
 	);
 
 	$result = array(
@@ -1696,9 +1703,12 @@ function wp_get_l10n_php_file_data( $php_file ) {
 		'X-Generator'        => '',
 	);
 
-	foreach ( $headers as $po_header => $php_header ) {
-		if ( isset( $data[ $php_header ] ) ) {
-			$result[ $po_header ] = $data[ $php_header ];
+	foreach ( $headers as $po_header => $php_headers ) {
+		foreach ( $php_headers as $php_header ) {
+			if ( isset( $data[ $php_header ] ) ) {
+				$result[ $po_header ] = $data[ $php_header ];
+				break;
+			}
 		}
 	}
 

tests/phpunit/data/l10n/translation-revision-date.l10n.php

@@ -0,0 +1,2 @@
+<?php
+return ['x-generator'=>'GlotPress/4.0.3','translation-revision-date'=>'2026-06-26 08:56:45+0000','plural-forms'=>'nplurals=2; plural=n != 1;','project-id-version'=>'Themes - Twenty Twenty-Five','language'=>'nl','messages'=>['Update %s now'=>'Werk %s nu bij']];

tests/phpunit/tests/l10n.php

@@ -154,6 +154,36 @@ public function test_wp_get_pomo_file_data() {
 		$this->assertNotEmpty( $array['X-Generator'] );
 	}
 
+	/**
+	 * Ensures the revision date is read from both spellings a `.l10n.php` file may use.
+	 *
+	 * GlotPress writes the revision date as `translation-revision-date`. Files generated
+	 * before that renaming use `po-revision-date`, so both have to resolve.
+	 *
+	 * @ticket 65809
+	 *
+	 * @covers ::wp_get_l10n_php_file_data
+	 */
+	public function test_wp_get_l10n_php_file_data_reads_revision_date() {
+		$current = wp_get_l10n_php_file_data( DIR_TESTDATA . '/l10n/translation-revision-date.l10n.php' );
+
+		$this->assertSame(
+			'2026-06-26 08:56:45+0000',
+			$current['PO-Revision-Date'],
+			'The revision date was not read from the translation-revision-date key.'
+		);
+		$this->assertSame( 'Themes - Twenty Twenty-Five', $current['Project-Id-Version'] );
+		$this->assertSame( 'GlotPress/4.0.3', $current['X-Generator'] );
+
+		$legacy = wp_get_l10n_php_file_data( DIR_TESTDATA . '/languages/de_CH.l10n.php' );
+
+		$this->assertSame(
+			'2024-01-31 19:08:22+0000',
+			$legacy['PO-Revision-Date'],
+			'The revision date was not read from the legacy po-revision-date key.'
+		);
+	}
+
 	/**
 	 * @ticket 44541
 	 *