I18N: Correct strict comparison in WP_Translations::translate_plural().

This ensures that the `$count` value is compared as an integer to account for plugins or themes passing a numeric string instead.

Follow-up to [57337].

Props dd32, mukesh27, swissspidy, pmbaldha, SergeyBiryukov.
Fixes #63642.

git-svn-id: https://develop.svn.wordpress.org/trunk@60484 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/l10n/class-wp-translations.php

@@ -124,7 +124,7 @@ public function translate_plural( $singular, $plural, $count = 1, $context = ''
 		}
 
 		// Fall back to the original with English grammar rules.
-		return ( 1 === $count ? $singular : $plural );
+		return ( 1 === (int) $count ? $singular : $plural );
 	}
 
 	/**

tests/phpunit/tests/l10n/wpTranslations.php

@@ -226,10 +226,16 @@ public function test_translate_plural() {
 	public function test_translate_plural_complex() {
 		load_textdomain( 'wp-tests-domain', DIR_TESTDATA . '/l10n/plural-complex.mo' );
 
+		$this->assertSame( '%s razpoložljiva posodobitev', _n( '%s update available', '%s updates available', '1', 'wp-tests-domain' ) ); // 1, 101, 201
 		$this->assertSame( '%s razpoložljiva posodobitev', _n( '%s update available', '%s updates available', 101, 'wp-tests-domain' ) ); // 1, 101, 201
 		$this->assertSame( '%s razpoložljivi posodobitvi', _n( '%s update available', '%s updates available', 102, 'wp-tests-domain' ) ); // 2, 102, 202
 		$this->assertSame( '%s razpoložljive posodobitve', _n( '%s update available', '%s updates available', 103, 'wp-tests-domain' ) ); // 3, 4, 103
 		$this->assertSame( '%s razpoložljivih posodobitev', _n( '%s update available', '%s updates available', 5, 'wp-tests-domain' ) ); // 0, 5, 6
+
+		// Test with strings that are not in the translation files.
+		$this->assertSame( 'Singular', _n( 'Singular', 'Plural', 1, 'wp-tests-domain' ) );
+		$this->assertSame( 'Singular', _n( 'Singular', 'Plural', '1', 'wp-tests-domain' ) );
+		$this->assertSame( 'Plural', _n( 'Singular', 'Plural', 2, 'wp-tests-domain' ) );
 	}
 
 	/**
@@ -239,10 +245,16 @@ public function test_translate_plural_complex() {
 	public function test_translate_plural_complex_php() {
 		load_textdomain( 'wp-tests-domain', DIR_TESTDATA . '/l10n/plural-complex.php' );
 
+		$this->assertSame( '%s razpoložljiva posodobitev', _n( '%s update available', '%s updates available', '1', 'wp-tests-domain' ) ); // 1, 101, 201
 		$this->assertSame( '%s razpoložljiva posodobitev', _n( '%s update available', '%s updates available', 101, 'wp-tests-domain' ) ); // 1, 101, 201
 		$this->assertSame( '%s razpoložljivi posodobitvi', _n( '%s update available', '%s updates available', 102, 'wp-tests-domain' ) ); // 2, 102, 202
 		$this->assertSame( '%s razpoložljive posodobitve', _n( '%s update available', '%s updates available', 103, 'wp-tests-domain' ) ); // 3, 4, 103
 		$this->assertSame( '%s razpoložljivih posodobitev', _n( '%s update available', '%s updates available', 5, 'wp-tests-domain' ) ); // 0, 5, 6
+
+		// Test with strings that are not in the translation files.
+		$this->assertSame( 'Singular', _n( 'Singular', 'Plural', 1, 'wp-tests-domain' ) );
+		$this->assertSame( 'Singular', _n( 'Singular', 'Plural', '1', 'wp-tests-domain' ) );
+		$this->assertSame( 'Plural', _n( 'Singular', 'Plural', 2, 'wp-tests-domain' ) );
 	}
 
 	/**