Show warning if association property name is same as table field.

src/ORM/Association.php

@@ -438,6 +438,14 @@ abstract class Association
         if ($name === null && !$this->_propertyName) {
             list(, $name) = pluginSplit($this->_name);
             $this->_propertyName = Inflector::underscore($name);
+            if (in_array($this->_propertyName, $this->_sourceTable->schema()->columns())) {
+                $msg = 'Association property name "%s" clashes with field of same name of table "%s".' .
+                    "\n" . 'You should explicitly specify the "propertyName" option.';
+                trigger_error(
+                    sprintf($msg, $this->_propertyName, $this->_sourceTable->table()),
+                    E_USER_WARNING
+                );
+            }
         }
         return $this->_propertyName;
     }

tests/TestCase/ORM/Association/BelongsToManyTest.php

@@ -700,10 +700,12 @@ class BelongsToManyTest extends TestCase
      */
     public function testSaveAssociatedEmptySetSuccess($value)
     {
+        $table = $this->getMock('Cake\ORM\Table', ['table'], [[]]);
+        $table->schema([]);
         $assoc = $this->getMock(
             '\Cake\ORM\Association\BelongsToMany',
             ['_saveTarget', 'replaceLinks'],
-            ['tags']
+            ['tags', ['sourceTable' => $table]]
         );
         $entity = new Entity([
             'id' => 1,
@@ -726,10 +728,12 @@ class BelongsToManyTest extends TestCase
      */
     public function testSaveAssociatedEmptySetUpdateSuccess($value)
     {
+        $table = $this->getMock('Cake\ORM\Table', ['table'], [[]]);
+        $table->schema([]);
         $assoc = $this->getMock(
             '\Cake\ORM\Association\BelongsToMany',
             ['_saveTarget', 'replaceLinks'],
-            ['tags']
+            ['tags', ['sourceTable' => $table]]
         );
         $entity = new Entity([
             'id' => 1,
@@ -755,10 +759,12 @@ class BelongsToManyTest extends TestCase
      */
     public function testSaveAssociatedWithReplace()
     {
+        $table = $this->getMock('Cake\ORM\Table', ['table'], [[]]);
+        $table->schema([]);
         $assoc = $this->getMock(
             '\Cake\ORM\Association\BelongsToMany',
             ['replaceLinks'],
-            ['tags']
+            ['tags', ['sourceTable' => $table]]
         );
         $entity = new Entity([
             'id' => 1,
@@ -782,10 +788,12 @@ class BelongsToManyTest extends TestCase
      */
     public function testSaveAssociatedWithReplaceReturnFalse()
     {
+        $table = $this->getMock('Cake\ORM\Table', ['table'], [[]]);
+        $table->schema([]);
         $assoc = $this->getMock(
             '\Cake\ORM\Association\BelongsToMany',
             ['replaceLinks'],
-            ['tags']
+            ['tags', ['sourceTable' => $table]]
         );
         $entity = new Entity([
             'id' => 1,

tests/TestCase/ORM/AssociationCollectionTest.php

@@ -284,7 +284,8 @@ class AssociationCollectionTest extends TestCase
      */
     public function testSaveChildrenFiltered()
     {
-        $table = $this->getMock('Cake\ORM\Table', [], [[]]);
+        $table = $this->getMock('Cake\ORM\Table', ['table'], [[]]);
+        $table->schema([]);
         $mockOne = $this->getMock(
             'Cake\ORM\Association\HasMany',
             ['saveAssociated'],