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framework/CHANGELOG.md

@@ -4,7 +4,7 @@ Yii Framework 2 Change Log
 2.0.14.2 under development
 ------------------------
 
-- Bug #15858: Fixed array undefined offset error calling Html::errorSummary with same error messages from different model attributes (FabrizioCaldarelli)
+- Bug #15858: Fixed `Undefined offset` error calling `yii\helpers\Html::errorSummary()` with the same error messages for different model attributes (FabrizioCaldarelli, silverfire)
 - Bug #15783: Regenerate CSRF token only when logging in directly (samdark)
 - Bug #15801: Fixed `has-error` CSS class assignment in `yii\widgets\ActiveField` when attribute name is prefixed with tabular index (FabrizioCaldarelli)
 - Bug #15792: Added missing `yii\db\QueryBuilder::conditionClasses` setter (silverfire)

framework/helpers/BaseHtml.php

@@ -1255,14 +1255,13 @@ class BaseHtml
             $lines = array_unique(array_merge($lines, $model->getErrorSummary($showAllErrors)));
         }
 
-        // Fix #15858 (FlorinRo) - If there are same message errors for different attributes, array_unique could skip some array key,
-        // so the next for cycle could fail because key missing.
-        // Applying array_values reorder array keys.
+        // If there are the same error messages for different attributes, array_unique will leave gaps
+        // between sequential keys. Applying array_values to reorder array keys.
         $lines = array_values($lines);
 
         if ($encode) {
-            for ($i = 0, $linesCount = count($lines); $i < $linesCount; $i++) {
-                $lines[$i] = Html::encode($lines[$i]);
+            foreach ($lines as &$line) {
+                $line = Html::encode($line);
             }
         }
 

tests/framework/helpers/HtmlTest.php

@@ -1321,6 +1321,7 @@ EOD;
 
     /**
      * Test that attributes that output same errors, return unique message error
+     * @see https://github.com/yiisoft/yii2/pull/15859
      */
     public function testCollectError()
     {