From 7c8cbc4ead92195fcd75ff269d36b7976bca28f9 Mon Sep 17 00:00:00 2001
From: Sangeetha <sangeethailango21@gmail.com>
Date: Mon, 24 Nov 2025 21:22:17 +0530
Subject: [PATCH] [WEB-4428] fix: duplicate labels with case insensitive
 (#7388)

Co-authored-by: sriramveeraghanta <veeraghanta.sriram@gmail.com>
---
 apps/api/plane/app/serializers/issue.py       | 13 ++++++
 apps/api/plane/app/views/issue/label.py       | 19 ++++++--
 .../tests/unit/serializers/test_label.py      | 43 +++++++++++++++++++
 3 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 apps/api/plane/tests/unit/serializers/test_label.py

diff --git a/apps/api/plane/app/serializers/issue.py b/apps/api/plane/app/serializers/issue.py
index 583b62fd6..21a286d5e 100644
--- a/apps/api/plane/app/serializers/issue.py
+++ b/apps/api/plane/app/serializers/issue.py
@@ -364,6 +364,19 @@ class LabelSerializer(BaseSerializer):
         ]
         read_only_fields = ["workspace", "project"]
 
+    def validate_name(self, value):
+        project_id = self.context.get("project_id")
+
+        label = Label.objects.filter(project_id=project_id, name__iexact=value)
+
+        if self.instance:
+            label = label.exclude(id=self.instance.pk)
+
+        if label.exists():
+            raise serializers.ValidationError(detail="LABEL_NAME_ALREADY_EXISTS")
+
+        return value
+
 
 class LabelLiteSerializer(BaseSerializer):
     class Meta:
diff --git a/apps/api/plane/app/views/issue/label.py b/apps/api/plane/app/views/issue/label.py
index 85e79c011..ad0a29080 100644
--- a/apps/api/plane/app/views/issue/label.py
+++ b/apps/api/plane/app/views/issue/label.py
@@ -39,7 +39,9 @@ class LabelViewSet(BaseViewSet):
     @allow_permission([ROLE.ADMIN])
     def create(self, request, slug, project_id):
         try:
-            serializer = LabelSerializer(data=request.data)
+            serializer = LabelSerializer(
+                data=request.data, context={"project_id": project_id}
+            )
             if serializer.is_valid():
                 serializer.save(project_id=project_id)
                 return Response(serializer.data, status=status.HTTP_201_CREATED)
@@ -64,8 +66,18 @@ class LabelViewSet(BaseViewSet):
                 {"error": "Label with the same name already exists in the project"},
                 status=status.HTTP_400_BAD_REQUEST,
             )
-        # call the parent method to perform the update
-        return super().partial_update(request, *args, **kwargs)
+
+        serializer = LabelSerializer(
+            instance=self.get_object(),
+            data=request.data,
+            context={"project_id": kwargs["project_id"]},
+            partial=True,
+        )
+
+        if serializer.is_valid():
+            serializer.save()
+            return Response(serializer.data)
+        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
 
     @invalidate_cache(path="/api/workspaces/:slug/labels/", url_params=True, user=False)
     @allow_permission([ROLE.ADMIN])
@@ -77,6 +89,7 @@ class BulkCreateIssueLabelsEndpoint(BaseAPIView):
     @allow_permission([ROLE.ADMIN])
     def post(self, request, slug, project_id):
         label_data = request.data.get("label_data", [])
+
         project = Project.objects.get(pk=project_id)
 
         labels = Label.objects.bulk_create(
diff --git a/apps/api/plane/tests/unit/serializers/test_label.py b/apps/api/plane/tests/unit/serializers/test_label.py
new file mode 100644
index 000000000..91cde1c4a
--- /dev/null
+++ b/apps/api/plane/tests/unit/serializers/test_label.py
@@ -0,0 +1,43 @@
+import pytest
+from plane.app.serializers import LabelSerializer
+from plane.db.models import Project, Label
+
+
+@pytest.mark.unit
+class TestLabelSerializer:
+    """Test the LabelSerializer"""
+
+    @pytest.mark.django_db
+    def test_label_serializer_create_valid_data(self, db, workspace):
+        """Test creating a label with valid data"""
+        project = Project.objects.create(
+            name="Test Project", identifier="TEST", workspace=workspace
+        )
+
+        serializer = LabelSerializer(
+            data={"name": "Test Label"},
+            context={"project_id": project.id},
+        )
+        assert serializer.is_valid()
+        assert serializer.errors == {}
+        serializer.save(project_id=project.id)
+
+        label = Label.objects.all().first()
+        assert label.name == "Test Label"
+        assert label.project == project
+        assert label
+
+    @pytest.mark.django_db
+    def test_label_serializer_create_duplicate_name(self, db, workspace):
+        """Test creating a label with a duplicate name"""
+        project = Project.objects.create(
+            name="Test Project", identifier="TEST", workspace=workspace
+        )
+
+        Label.objects.create(name="Test Label", project=project)
+
+        serializer = LabelSerializer(
+            data={"name": "Test Label"}, context={"project_id": project.id}
+        )
+        assert not serializer.is_valid()
+        assert serializer.errors == {"name": ["LABEL_NAME_ALREADY_EXISTS"]}