Issue #3484830 by smovs, pdureau, mogtofu33: Warning if "is iterable" test found

modules/ui_patterns_devel/src/Plugin/TwigValidatorRule/TwigValidatorRuleTestExpr.php

@@ -98,12 +98,11 @@ final class TwigValidatorRuleTestExpr extends TwigValidatorRulePluginBase {
     switch ($name) {
       case 'empty':
         $message = 'The exact same as just testing the variable, empty is not needed.';
-      // @phpcs:disable
-      // @todo enable when Twig 3.11 with better iterable.
-      // case 'iterable':
-      //   $message = new TranslatableMarkup('Return true for mapping and sequence.');
-      //   return [ValidatorMessage::createForNode($id, $node, $message, RfcLogLevel::WARNING)];
-      // @phpcs:enable
+        break;
+
+      case 'iterable':
+        $message = '`is iterable` test is too ambiguous. Use `is sequence` or `is mapping`.';
+        break;
     }
     return RfcLogLevel::WARNING;
   }

modules/ui_patterns_devel/tests/src/Kernel/TwigValidatorRule/TwigValidatorRuleTestExprTest.php

@@ -30,6 +30,7 @@ final class TwigValidatorRuleTestExprTest extends TwigValidatorTestBase {
         "{% set foo = 'foo' %}
         {% if foo is defined %}{% endif %}
         {% if foo is empty %}{% endif %}
+        {% if foo is iterable %}{% endif %}
         {{ foo is null }}
         {{ foo ?? 'bar' }}
         {% if foo is same as(false) %}{% endif %}
@@ -37,9 +38,10 @@ final class TwigValidatorRuleTestExprTest extends TwigValidatorTestBase {
         [
           [2, 'Not needed in Drupal because strict_variables=false.', RfcLogLevel::WARNING],
           [3, 'The exact same as just testing the variable, empty is not needed.', RfcLogLevel::WARNING],
-          [4, 'Not needed in Drupal because strict_variables=false.', RfcLogLevel::WARNING],
-          [5, 'Use `|default(foo)` filter instead of null ternary `??`.', RfcLogLevel::WARNING],
-          [6, 'Equivalent to strict comparison in PHP, often too strict.', RfcLogLevel::ERROR],
+          [4, '`is iterable` test is too ambiguous. Use `is sequence` or `is mapping`.', RfcLogLevel::WARNING],
+          [5, 'Not needed in Drupal because strict_variables=false.', RfcLogLevel::WARNING],
+          [6, 'Use `|default(foo)` filter instead of null ternary `??`.', RfcLogLevel::WARNING],
+          [7, 'Equivalent to strict comparison in PHP, often too strict.', RfcLogLevel::ERROR],
         ],
       ],
     ];