I18N: Add a new way to determine whether a translation is available.

A new `has_translation()` function can be used to determine whether a translation exists for a given string.

Props louiswol94, swissspidy, drzraf, ckanitz, tomhine, mchirag2002, samuelsilvapt.
Fixes #52696.



git-svn-id: https://develop.svn.wordpress.org/trunk@59029 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/l10n.php

@@ -1988,3 +1988,17 @@ function wp_get_word_count_type() {
 
 	return $wp_locale->get_word_count_type();
 }
+
+/**
+ * Returns a boolean to indicate whether a translation exists for a given string with optional text domain and locale.
+ *
+ * @since 6.7.0
+ *
+ * @param string  $singular   Singular translation to check.
+ * @param string  $textdomain Optional. Text domain. Default 'default'.
+ * @param ?string $locale     Optional. Locale. Default current locale.
+ * @return bool  True if the translation exists, false otherwise.
+ */
+function has_translation( string $singular, string $textdomain = 'default', ?string $locale = null ): bool {
+	return WP_Translation_Controller::get_instance()->has_translation( $singular, $textdomain, $locale );
+}

src/wp-includes/l10n/class-wp-translation-controller.php

@@ -434,4 +434,22 @@ protected function get_files( string $textdomain = 'default', ?string $locale =
 
 		return $this->loaded_translations[ $locale ][ $textdomain ] ?? array();
 	}
+
+	/**
+	 * Returns a boolean to indicate whether a translation exists for a given string with optional text domain and locale.
+	 *
+	 * @since 6.7.0
+	 *
+	 * @param string  $singular   Singular translation to check.
+	 * @param string  $textdomain Optional. Text domain. Default 'default'.
+	 * @param ?string $locale     Optional. Locale. Default current locale.
+	 * @return bool  True if the translation exists, false otherwise.
+	 */
+	public function has_translation( string $singular, string $textdomain = 'default', ?string $locale = null ): bool {
+		if ( null === $locale ) {
+			$locale = $this->current_locale;
+		}
+
+		return false !== $this->locate_translation( $singular, $textdomain, $locale );
+	}
 }

tests/phpunit/tests/l10n/wpTranslationController.php

@@ -361,4 +361,51 @@ public function test_switch_to_locale_translations_stay_loaded_custom_textdomain
 		$this->assertSame( 'Este es un plugin dummy', $actual );
 		$this->assertSame( 'This is a dummy plugin', $after );
 	}
+
+	/**
+	 * @ticket 52696
+	 * @covers ::has_translation
+	 */
+	public function test_has_translation_with_existing_translation() {
+		load_textdomain( 'wp-tests-domain', DIR_TESTDATA . '/pomo/simple.mo' );
+		$this->assertTrue( WP_Translation_Controller::get_instance()->has_translation( 'baba', 'wp-tests-domain', 'en_US' ) );
+	}
+
+	/**
+	 * @ticket 52696
+	 * @covers ::has_translation
+	 */
+	public function test_has_translation_with_no_translation() {
+		$this->assertFalse( WP_Translation_Controller::get_instance()->has_translation( 'Goodbye', 'wp-tests-domain', 'en_US' ) );
+	}
+
+	/**
+	 * @ticket 52696
+	 * @covers ::has_translation
+	 */
+	public function test_has_translation_with_different_textdomain() {
+		load_textdomain( 'wp-tests-domain', DIR_TESTDATA . '/pomo/simple.mo' );
+		$this->assertFalse( WP_Translation_Controller::get_instance()->has_translation( 'baba', 'custom-domain', 'en_US' ) );
+	}
+
+	/**
+	 * @ticket 52696
+	 * @covers ::has_translation
+	 */
+	public function test_has_translation_with_different_locale() {
+		switch_to_locale( 'es_ES' );
+		load_textdomain( 'wp-tests-domain', DIR_TESTDATA . '/pomo/simple.mo' );
+		$actual = WP_Translation_Controller::get_instance()->has_translation( 'baba', 'wp-tests-domain', 'es_ES' );
+		restore_previous_locale();
+		$this->assertTrue( $actual );
+	}
+
+	/**
+	 * @ticket 52696
+	 * @covers ::has_translation
+	 */
+	public function test_has_translation_with_no_locale_provided() {
+		load_textdomain( 'wp-tests-domain', DIR_TESTDATA . '/pomo/simple.mo' );
+		$this->assertTrue( WP_Translation_Controller::get_instance()->has_translation( 'baba', 'wp-tests-domain' ) );
+	}
 }