Fixing error 500 when importing two milestones with the same name

taiga/export_import/serializers.py

@@ -296,6 +296,23 @@ class MilestoneExportSerializer(serializers.ModelSerializer):
     watchers = UserRelatedField(many=True, required=False)
     modified_date = serializers.DateTimeField(required=False)
 
+    def __init__(self, *args, **kwargs):
+        project = kwargs.pop('project', None)
+        super(MilestoneExportSerializer, self).__init__(*args, **kwargs)
+        if project:
+            self.project = project
+
+    def validate_name(self, attrs, source):
+        """
+        Check the milestone name is not duplicated in the project
+        """
+        name = attrs[source]
+        qs = self.project.milestones.filter(name=name)
+        if qs.exists():
+              raise serializers.ValidationError("Name duplicated for the project")
+
+        return attrs
+
     class Meta:
         model = milestones_models.Milestone
         exclude = ('id', 'project')

taiga/export_import/service.py

@@ -185,7 +185,7 @@ def store_task(project, task):
 
 
 def store_milestone(project, milestone):
-    serialized = serializers.MilestoneExportSerializer(data=milestone)
+    serialized = serializers.MilestoneExportSerializer(data=milestone, project=project)
     if serialized.is_valid():
         serialized.object.project = project
         serialized.object._importing = True

tests/integration/test_importer_api.py

@@ -637,3 +637,21 @@ def test_valid_milestone_import(client):
     response = client.post(url, json.dumps(data), content_type="application/json")
     assert response.status_code == 201
     response_data = json.loads(response.content.decode("utf-8"))
+
+def test_milestone_import_duplicated_milestone(client):
+    user = f.UserFactory.create()
+    project = f.ProjectFactory.create(owner=user)
+    client.login(user)
+
+    url = reverse("importer-milestone", args=[project.pk])
+    data = {
+        "name": "Imported milestone",
+        "estimated_start": "2014-10-10",
+        "estimated_finish": "2014-10-20",
+    }
+    # We create twice the same milestone
+    response = client.post(url, json.dumps(data), content_type="application/json")
+    response = client.post(url, json.dumps(data), content_type="application/json")
+    assert response.status_code == 400
+    response_data = json.loads(response.content.decode("utf-8"))
+    assert response_data["milestones"][0]["name"][0] == "Name duplicated for the project"