Fixes #2653: Fixed the bug that unsetting an unpopulated AR relation would…

framework/CHANGELOG.md

@@ -52,6 +52,7 @@ Yii Framework 2 Change Log
 - Bug #2559: Going back on browser history breaks GridView filtering with `Pjax` (tonydspaniard)
 - Bug #2607: `yii message` tool wasn't updating `message` table (mitalcoi)
 - Bug #2624: Html::textArea() should respect "name" option. (qiangxue)
+- Bug #2653: Fixed the bug that unsetting an unpopulated AR relation would trigger exception (qiangxue)
 - Bug: Fixed `Call to a member function registerAssetFiles() on a non-object` in case of wrong `sourcePath` for an asset bundle (samdark)
 - Bug: Fixed incorrect event name for `yii\jui\Spinner` (samdark)
 - Bug: Json::encode() did not handle objects that implement JsonSerializable interface correctly (cebe)

framework/db/ActiveRecordInterface.php

@@ -272,9 +272,10 @@ interface ActiveRecordInterface
 	 * (normally this would be a relational [[ActiveQuery]] object).
 	 * It can be declared in either the ActiveRecord class itself or one of its behaviors.
 	 * @param string $name the relation name
+	 * @param boolean $throwException whether to throw exception if the relation does not exist.
 	 * @return ActiveQueryInterface the relational query object
 	 */
-	public function getRelation($name);
+	public function getRelation($name, $throwException = true);
 
 	/**
 	 * Establishes the relationship between two records.

framework/db/BaseActiveRecord.php

@@ -305,7 +305,7 @@ abstract class BaseActiveRecord extends Model implements ActiveRecordInterface
 			unset($this->_attributes[$name]);
 		} elseif (array_key_exists($name, $this->_related)) {
 			unset($this->_related[$name]);
-		} else {
+		} elseif ($this->getRelation($name, false) === null) {
 			parent::__unset($name);
 		}
 	}
@@ -1063,20 +1063,30 @@ abstract class BaseActiveRecord extends Model implements ActiveRecordInterface
 	 * A relation is defined by a getter method which returns an [[ActiveQueryInterface]] object.
 	 * It can be declared in either the Active Record class itself or one of its behaviors.
 	 * @param string $name the relation name
-	 * @return ActiveQueryInterface|ActiveQuery the relational query object
+	 * @param boolean $throwException whether to throw exception if the relation does not exist.
+	 * @return ActiveQueryInterface|ActiveQuery the relational query object. If the relation does not exist
+	 * and `$throwException` is false, null will be returned.
 	 * @throws InvalidParamException if the named relation does not exist.
 	 */
-	public function getRelation($name)
+	public function getRelation($name, $throwException = true)
 	{
 		$getter = 'get' . $name;
 		try {
 			// the relation could be defined in a behavior
 			$relation = $this->$getter();
 		} catch (UnknownMethodException $e) {
-			throw new InvalidParamException(get_class($this) . ' has no relation named "' . $name . '".', 0, $e);
+			if ($throwException) {
+				throw new InvalidParamException(get_class($this) . ' has no relation named "' . $name . '".', 0, $e);
+			} else {
+				return null;
+			}
 		}
 		if (!$relation instanceof ActiveQueryInterface) {
-			throw new InvalidParamException(get_class($this) . ' has no relation named "' . $name . '".');
+			if ($throwException) {
+				throw new InvalidParamException(get_class($this) . ' has no relation named "' . $name . '".');
+			} else {
+				return null;
+			}
 		}
 
 		if (method_exists($this, $getter)) {
@@ -1084,7 +1094,11 @@ abstract class BaseActiveRecord extends Model implements ActiveRecordInterface
 			$method = new \ReflectionMethod($this, $getter);
 			$realName = lcfirst(substr($method->getName(), 3));
 			if ($realName !== $name) {
-				throw new InvalidParamException('Relation names are case sensitive. ' . get_class($this) . " has a relation named \"$realName\" instead of \"$name\".");
+				if ($throwException) {
+					throw new InvalidParamException('Relation names are case sensitive. ' . get_class($this) . " has a relation named \"$realName\" instead of \"$name\".");
+				} else {
+					return null;
+				}
 			}
 		}
 
@@ -1367,4 +1381,16 @@ abstract class BaseActiveRecord extends Model implements ActiveRecordInterface
 		$fields = array_keys($this->getRelatedRecords());
 		return array_combine($fields, $fields);
 	}
+
+	/**
+	 * Sets the element value at the specified offset to null.
+	 * This method is required by the SPL interface `ArrayAccess`.
+	 * It is implicitly called when you use something like `unset($model[$offset])`.
+	 * @param mixed $offset the offset to unset element
+	 */
+	public function offsetUnset($offset)
+	{
+		// use unset to trigger __unset()
+		unset($this->$offset);
+	}
 }

tests/unit/framework/ar/ActiveRecordTestTrait.php

@@ -184,7 +184,7 @@ trait ActiveRecordTestTrait
 		$this->assertEquals(['user3', 'user2', 'user1'], $this->callCustomerFind()->orderBy(['name' => SORT_DESC])->column('name'));
 	}
 
-	public function testfindIndexBy()
+	public function testFindIndexBy()
 	{
 		$customerClass = $this->getCustomerClass();
 		/** @var TestCase|ActiveRecordTestTrait $this */
@@ -205,7 +205,7 @@ trait ActiveRecordTestTrait
 		$this->assertTrue($customers['3-user3'] instanceof $customerClass);
 	}
 
-	public function testfindIndexByAsArray()
+	public function testFindIndexByAsArray()
 	{
 		/** @var TestCase|ActiveRecordTestTrait $this */
 		// indexBy + asArray
@@ -399,6 +399,10 @@ trait ActiveRecordTestTrait
 		$this->assertEquals(2, count($orders));
 		$this->assertEquals(1, count($customer->relatedRecords));
 
+		// unset
+		unset($customer['orders']);
+		$this->assertFalse($customer->isRelationPopulated('orders'));
+
 		/** @var Customer $customer */
 		$customer = $this->callCustomerFind(2);
 		$this->assertFalse($customer->isRelationPopulated('orders'));
@@ -422,6 +426,9 @@ trait ActiveRecordTestTrait
 		$this->assertEquals(1, count($customers[1]->orders));
 		$this->assertEquals(2, count($customers[2]->orders));
 		$this->assertEquals(0, count($customers[3]->orders));
+		// unset
+		unset($customers[1]->orders);
+		$this->assertFalse($customers[1]->isRelationPopulated('orders'));
 
 		$customer = $this->callCustomerFind()->where(['id' => 1])->with('orders')->one();
 		$this->assertTrue($customer->isRelationPopulated('orders'));