Serializer previous_diff_id

backend/code_review_backend/issues/v2/api.py

@@ -11,12 +11,33 @@
 from rest_framework.generics import ListAPIView
 
 from code_review_backend.issues.models import Diff, IssueLink
-from code_review_backend.issues.v2.serializers import IssueLinkHashSerializer
+from code_review_backend.issues.v2.serializers import DiffIssuesSerializer
 
 
 class IssueList(ListAPIView):
-    serializer_class = IssueLinkHashSerializer
+    """
+    Returns issues that are linked to a diff, and depending on the selected mode:
+    * known: Issues that have also being detected from the base repository (e.g. mozilla-central).
+        `previous_diff_id` is always returned as null when listing known issues.
+    * unresolved: Issues that were linked to the previous diff of the same parent revision, and are
+        still present on the current diff. Filters out issues that are known by the backend.
+    * closed: Issues that were listed on the previous diff of the same parent revision, but does
+        not exist on the current diff.
+
+    This endpoint does not uses pagination.
+    """
+
     allowed_modes = ["unresolved", "known", "closed"]
+    pagination_class = None
+
+    def get_serializer(self, queryset, many=True):
+        return DiffIssuesSerializer(
+            {
+                "previous_diff_id": self.previous_diff,
+                "issues": queryset,
+            },
+            context=self.get_serializer_context(),
+        )
 
     @cached_property
     def diff(self):
@@ -26,13 +47,14 @@ def diff(self):
 
     @cached_property
     def previous_diff(self):
-        previous_diff = (
+        if self.mode == "known":
+            # No need to search for a previous diff for known issues
+            return None
+        return (
             self.diff.revision.diffs.filter(created__lt=self.diff.created)
             .order_by("created")
             .last()
         )
-        if not previous_diff:
-            raise BadRequest("No previous diff was found to compare issues")
 
     @cached_property
     def mode(self):
@@ -54,9 +76,6 @@ def distinct_issues(self, qs):
 
     @property
     def known_issues(self):
-        """
-        Issues that have also being detected from the base repository (e.g. mozilla-central).
-        """
         return self.distinct_issues(
             self.diff.issue_links.annotate(
                 known=Exists(
@@ -70,11 +89,8 @@ def known_issues(self):
 
     @property
     def unresolved_issues(self):
-        """
-        Issues that were linked to the previous diff of the same
-        parent revision, and are still present on the current diff.
-        Filters out issues that are known by the backend.
-        """
+        if not self.previous_diff:
+            raise BadRequest("No previous diff was found to compare issues")
         return self.distinct_issues(
             self.known_issues.filter(known=False).annotate(
                 unresolved=Exists(
@@ -88,10 +104,8 @@ def unresolved_issues(self):
 
     @property
     def closed_issues(self):
-        """
-        Issues that were listed on the previous diff of the same
-        parent revision, but does not exist on the current diff.
-        """
+        if not self.previous_diff:
+            raise BadRequest("No previous diff was found to compare issues")
         return self.distinct_issues(
             self.previous_diff.issue_links.annotate(
                 closed=~Exists(

backend/code_review_backend/issues/v2/serializers.py

@@ -12,3 +12,8 @@ class IssueLinkHashSerializer(serializers.ModelSerializer):
     class Meta:
         model = IssueLink
         fields = ("id", "hash")
+
+
+class DiffIssuesSerializer(serializers.Serializer):
+    previous_diff_id = serializers.UUIDField(allow_null=True, read_only=True)
+    issues = IssueLinkHashSerializer(many=True)