Fix issue when unlinking Gitlab account

app/Model/Base.php

@@ -96,6 +96,22 @@ abstract class Base extends \Core\Base
         }
     }
 
+    /**
+     * Force some fields to be null if empty
+     *
+     * @access public
+     * @param  array        $values    Input array
+     * @param  string[]     $keys      List of keys
+     */
+    public function convertNullFields(array &$values, array $keys)
+    {
+        foreach ($keys as $key) {
+            if (array_key_exists($key, $values) && empty($values[$key])) {
+                $values[$key] = null;
+            }
+        }
+    }
+
     /**
      * Build SQL condition for a given time range
      *

app/Model/User.php

@@ -279,7 +279,7 @@ class User extends Base
 
         $this->removeFields($values, array('confirmation', 'current_password'));
         $this->resetFields($values, array('is_admin', 'is_ldap_user', 'is_project_admin', 'disable_login_form'));
-        $this->removeEmptyFields($values, array('gitlab_id'));
+        $this->convertNullFields($values, array('gitlab_id'));
         $this->convertIntegerFields($values, array('gitlab_id'));
     }
 

doc/gitlab-authentication.markdown

@@ -76,3 +76,8 @@ Kanboard uses these information from your Gitlab profile:
 - Gitlab unique id
 
 The Gitlab unique id is used to link the local user account and the Gitlab account.
+
+Known issues
+------------
+
+Gitlab OAuth will work only with url rewrite enabled. At the moment, Gitlab doesn't support callback url with query string parameters. See [Gitlab issue](https://gitlab.com/gitlab-org/gitlab-ce/issues/2443)

tests/units/Model/UserTest.php

@@ -250,7 +250,7 @@ class UserTest extends Base
         );
 
         $u->prepare($input);
-        $this->assertEquals(array(), $input);
+        $this->assertEquals(array('gitlab_id' => null), $input);
 
         $input = array(
             'gitlab_id' => 'something',
@@ -325,8 +325,11 @@ class UserTest extends Base
     public function testUpdate()
     {
         $u = new User($this->container);
-        $this->assertNotFalse($u->create(array('username' => 'toto', 'password' => '123456', 'name' => 'Toto')));
+        $this->assertEquals(2, $u->create(array('username' => 'toto', 'password' => '123456', 'name' => 'Toto')));
+        $this->assertEquals(3, $u->create(array('username' => 'plop', 'gitlab_id' => '123')));
+
         $this->assertTrue($u->update(array('id' => 2, 'username' => 'biloute')));
+        $this->assertTrue($u->update(array('id' => 3, 'gitlab_id' => '')));
 
         $user = $u->getById(2);
         $this->assertNotFalse($user);
@@ -335,6 +338,10 @@ class UserTest extends Base
         $this->assertEquals('Toto', $user['name']);
         $this->assertEquals(0, $user['is_admin']);
         $this->assertEquals(0, $user['is_ldap_user']);
+
+        $user = $u->getById(3);
+        $this->assertNotEmpty($user);
+        $this->assertEquals(null, $user['gitlab_id']);
     }
 
     public function testRemove()