i18n: Ensure empty strings are consistently translated to ''.

This changeset fixes an edge case where empty strings were wrongly translated to `'0'` (falsey value) instead of `''` (empty string).

Props Chouby, manooweb, rafiahmedd, lopo.
Fixes #55941.


git-svn-id: https://develop.svn.wordpress.org/trunk@54315 602fd350-edb4-49c9-b593-d223f7449a82

Author: audrasjb

src/wp-includes/pomo/entry.php

@@ -87,10 +87,10 @@ public function Translation_Entry( $args = array() ) {
 		/**
 		 * Generates a unique key for this entry.
 		 *
-		 * @return string|false The key or false if the entry is empty.
+		 * @return string|false The key or false if the entry is null.
 		 */
 		public function key() {
-			if ( null === $this->singular || '' === $this->singular ) {
+			if ( null === $this->singular ) {
 				return false;
 			}
 

tests/phpunit/tests/pomo/translations.php

@@ -127,4 +127,31 @@ public function test_digit_and_merge() {
 		$this->assertSame( '1', $domain->translate( '1' ) );
 	}
 
+	/**
+	 * @ticket 55941
+	 */
+	public function test_translate_falsy_key() {
+		$entry_empty = new Translation_Entry(
+			array(
+				'singular'     => '',
+				'translations' => array(
+					'',
+				),
+			)
+		);
+		$entry_zero  = new Translation_Entry(
+			array(
+				'singular'     => '0',
+				'translations' => array(
+					'0',
+				),
+			)
+		);
+		$po          = new Translations();
+		$po->add_entry( $entry_empty );
+		$po->add_entry( $entry_zero );
+
+		$this->assertSame( '', $po->translate( '' ) );
+		$this->assertSame( '0', $po->translate( '0' ) );
+	}
 }