[Backport] Fixing problem when PATCH in a resource using prefetch_related

taiga/base/serializers.py

@@ -31,7 +31,7 @@ class TagsField(serializers.WritableField):
     def from_native(self, data):
         if not data:
             return data
-            
+
         ret = sum([tag.split(",") for tag in data], [])
         return ret
 
@@ -144,3 +144,16 @@ class ModelSerializer(serializers.ModelSerializer):
             if field:
                 field.required = True
         return super().perform_validation(attrs)
+
+    def save(self, **kwargs):
+        """
+        Due to DRF bug with M2M fields we refresh object state from database
+        directly if object is models.Model type and it contains m2m fields
+
+        See: https://github.com/tomchristie/django-rest-framework/issues/1556
+        """
+        self.object = super(serializers.ModelSerializer, self).save(**kwargs)
+        model = self.Meta.model
+        if model._meta.model._meta.local_many_to_many and self.object.pk:
+            self.object = model.objects.get(pk=self.object.pk)
+        return self.object

taiga/projects/issues/serializers.py

@@ -16,7 +16,9 @@
 
 from rest_framework import serializers
 
-from taiga.base.serializers import Serializer, TagsField, NeighborsSerializerMixin, PgArrayField
+from taiga.base.serializers import (Serializer, TagsField, NeighborsSerializerMixin, 
+        PgArrayField, ModelSerializer)
+
 from taiga.mdrender.service import render as mdrender
 from taiga.projects.validators import ProjectExistsValidator
 from taiga.projects.notifications.validators import WatchersValidator
@@ -24,7 +26,7 @@ from taiga.projects.notifications.validators import WatchersValidator
 from . import models
 
 
-class IssueSerializer(WatchersValidator, serializers.ModelSerializer):
+class IssueSerializer(WatchersValidator, ModelSerializer):
     tags = TagsField(required=False)
     external_reference = PgArrayField(required=False)
     is_closed = serializers.Field(source="is_closed")
@@ -61,7 +63,7 @@ class IssueNeighborsSerializer(NeighborsSerializerMixin, IssueSerializer):
         return NeighborIssueSerializer(neighbor).data
 
 
-class NeighborIssueSerializer(serializers.ModelSerializer):
+class NeighborIssueSerializer(ModelSerializer):
     class Meta:
         model = models.Issue
         fields = ("id", "ref", "subject")

taiga/projects/tasks/serializers.py

@@ -16,7 +16,9 @@
 
 from rest_framework import serializers
 
-from taiga.base.serializers import Serializer, TagsField, NeighborsSerializerMixin, PgArrayField
+from taiga.base.serializers import (Serializer, TagsField, NeighborsSerializerMixin,
+        PgArrayField, ModelSerializer)
+        
 from taiga.mdrender.service import render as mdrender
 from taiga.projects.validators import ProjectExistsValidator
 from taiga.projects.milestones.validators import SprintExistsValidator
@@ -26,7 +28,7 @@ from taiga.projects.notifications.validators import WatchersValidator
 from . import models
 
 
-class TaskSerializer(WatchersValidator, serializers.ModelSerializer):
+class TaskSerializer(WatchersValidator, ModelSerializer):
     tags = TagsField(required=False, default=[])
     external_reference = PgArrayField(required=False)
     comment = serializers.SerializerMethodField("get_comment")
@@ -63,7 +65,7 @@ class TaskNeighborsSerializer(NeighborsSerializerMixin, TaskSerializer):
         return NeighborTaskSerializer(neighbor).data
 
 
-class NeighborTaskSerializer(serializers.ModelSerializer):
+class NeighborTaskSerializer(ModelSerializer):
     class Meta:
         model = models.Task
         fields = ("id", "ref", "subject")

taiga/projects/userstories/serializers.py

@@ -18,7 +18,9 @@ import json
 from django.apps import apps
 from rest_framework import serializers
 
-from taiga.base.serializers import Serializer, TagsField, NeighborsSerializerMixin, PgArrayField
+from taiga.base.serializers import (Serializer, TagsField, NeighborsSerializerMixin,
+        PgArrayField, ModelSerializer)
+
 from taiga.mdrender.service import render as mdrender
 from taiga.projects.validators import ProjectExistsValidator, UserStoryStatusExistsValidator
 from taiga.projects.userstories.validators import UserStoryExistsValidator
@@ -37,7 +39,7 @@ class RolePointsField(serializers.WritableField):
         return json.loads(obj)
 
 
-class UserStorySerializer(WatchersValidator, serializers.ModelSerializer):
+class UserStorySerializer(WatchersValidator, ModelSerializer):
     tags = TagsField(default=[], required=False)
     external_reference = PgArrayField(required=False)
     points = RolePointsField(source="role_points", required=False)
@@ -95,7 +97,7 @@ class UserStoryNeighborsSerializer(NeighborsSerializerMixin, UserStorySerializer
         return NeighborUserStorySerializer(neighbor).data
 
 
-class NeighborUserStorySerializer(serializers.ModelSerializer):
+class NeighborUserStorySerializer(ModelSerializer):
     class Meta:
         model = models.UserStory
         fields = ("id", "ref", "subject")