Issue #3173103 by TolstoyDotCom, aludescher, smustgrave, J., jonathan1055, TR:...

Issue #3173103 by TolstoyDotCom, aludescher, smustgrave, J., jonathan1055, TR: False positives when identifying what is a placeholder, for deprecation error

core/lib/Drupal/Component/Render/FormattableMarkup.php

@@ -241,8 +241,10 @@ protected static function placeholderFormat($string, array $args) {
           break;
 
         default:
-          // Warn for random variables that won't be replaced.
-          trigger_error(sprintf('Invalid placeholder (%s) with string: "%s"', $key, $string), E_USER_WARNING);
+          if (!ctype_alnum($key[0])) {
+            // Warn for random placeholders that won't be replaced.
+            trigger_error(sprintf('Invalid placeholder (%s) with string: "%s"', $key, $string), E_USER_WARNING);
+          }
           // No replacement possible therefore we can discard the argument.
           unset($args[$key]);
           break;

core/tests/Drupal/Tests/Component/Render/FormattableMarkupTest.php

@@ -117,12 +117,12 @@ public function testUnexpectedPlaceholder($string, $arguments, $error_number, $e
    */
   public function providerTestUnexpectedPlaceholder() {
     return [
-      ['Non alpha starting character: ~placeholder', ['~placeholder' => 'replaced'], E_USER_WARNING, 'Invalid placeholder (~placeholder) with string: "Non alpha starting character: ~placeholder"'],
-      ['Alpha starting character: placeholder', ['placeholder' => 'replaced'], E_USER_WARNING, 'Invalid placeholder (placeholder) with string: "Alpha starting character: placeholder"'],
+      ['Non alpha, non-allowed starting character: ~placeholder', ['~placeholder' => 'replaced'], E_USER_WARNING, 'Invalid placeholder (~placeholder) with string: "Non alpha, non-allowed starting character: ~placeholder"'],
+      ['Alpha starting character: placeholder', ['placeholder' => 'replaced'], NULL, ''],
       // Ensure that where the placeholder is located in the string is
       // irrelevant.
-      ['placeholder', ['placeholder' => 'replaced'], E_USER_WARNING, 'Invalid placeholder (placeholder) with string: "placeholder"'],
-      ['No replacements', ['foo' => 'bar'], E_USER_WARNING, 'Invalid placeholder (foo) with string: "No replacements"'],
+      ['placeholder', ['placeholder' => 'replaced'], NULL, ''],
+      ['No replacements', ['foo' => 'bar'], NULL, ''],
     ];
   }