Fixed `Component::off()` not to throw an exception

Fixes #15822

framework/CHANGELOG.md

@@ -6,6 +6,7 @@ Yii Framework 2 Change Log
 
 - 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)
+- Bug #15822: Fixed `yii\base\Component::off()` not to throw an exception when handler does not exist (silverfire)
 
 
 2.0.14.1 February 24, 2018

framework/base/Component.php

@@ -556,9 +556,9 @@ class Component extends BaseObject
             return true;
         }
 
+        $removed = false;
         // plain event names
         if (isset($this->_events[$name])) {
-            $removed = false;
             foreach ($this->_events[$name] as $i => $event) {
                 if ($event[0] === $handler) {
                     unset($this->_events[$name][$i]);
@@ -572,18 +572,19 @@ class Component extends BaseObject
         }
 
         // wildcard event names
-        $removed = false;
-        foreach ($this->_eventWildcards[$name] as $i => $event) {
-            if ($event[0] === $handler) {
-                unset($this->_eventWildcards[$name][$i]);
-                $removed = true;
+        if (isset($this->_eventWildcards[$name])) {
+            foreach ($this->_eventWildcards[$name] as $i => $event) {
+                if ($event[0] === $handler) {
+                    unset($this->_eventWildcards[$name][$i]);
+                    $removed = true;
+                }
             }
-        }
-        if ($removed) {
-            $this->_eventWildcards[$name] = array_values($this->_eventWildcards[$name]);
-            // remove empty wildcards to save future redundant regex checks:
-            if (empty($this->_eventWildcards[$name])) {
-                unset($this->_eventWildcards[$name]);
+            if ($removed) {
+                $this->_eventWildcards[$name] = array_values($this->_eventWildcards[$name]);
+                // remove empty wildcards to save future redundant regex checks:
+                if (empty($this->_eventWildcards[$name])) {
+                    unset($this->_eventWildcards[$name]);
+                }
             }
         }
 

tests/framework/base/ComponentTest.php

@@ -436,6 +436,15 @@ class ComponentTest extends TestCase
         $this->assertFalse($this->component->hasEventHandlers('foo'));
         $this->assertFalse($this->component->off('foo'));
     }
+
+    public function testDetachNotAttachedHandler()
+    {
+        $obj = new NewComponent();
+
+        $obj->on('test', [$this, 'handler']);
+        $this->assertFalse($obj->off('test', [$this, 'handler2']), 'Trying to remove the handler that is not attached');
+        $this->assertTrue($obj->off('test', [$this, 'handler']), 'Trying to remove the attached handler');
+    }
 }
 
 class NewComponent extends Component