feat(code-mappings): Allow multiple source roots per stack root (#111704)

## Summary

- Change unique constraint on `RepositoryProjectPathConfig` from
`(project, stack_root)` to `(project, stack_root, source_root)`
- Update single-mapping serializer validation to include `source_root`
in duplicate check
- Update bulk endpoint upsert key to match on `(stack_root,
source_root)` instead of just `stack_root`

This allows the same stack trace root (e.g. `io/sentry/opentelemetry`)
to map to multiple source paths in the repo (e.g.
`sentry-opentelemetry-core/src/...` and
`sentry-opentelemetry-bootstrap/src/...`), which is needed for monorepos
with shared package prefixes across modules.

Stack trace resolution already handles this correctly — it iterates all
mappings sorted by specificity and uses the first match that resolves to
a real file.

## Test plan

- [x] All 63 existing tests pass (bulk + single endpoints)
- [x] Updated tests to reflect new constraint semantics
- [ ] Deploy migration and verify with real monorepo upload

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: romtsn

migrations_lockfile.txt

@@ -31,7 +31,7 @@ replays: 0007_organizationmember_replay_access
 
 seer: 0005_delete_seerorganizationsettings
 
-sentry: 1057_drop_legacy_alert_rule_tables
+sentry: 1058_change_code_mapping_unique_constraint
 
 social_auth: 0003_social_auth_json_field
 

src/sentry/integrations/api/endpoints/organization_code_mappings.py

@@ -70,13 +70,15 @@ def organization(self):
 
     def validate(self, attrs):
         query = RepositoryProjectPathConfig.objects.filter(
-            project_id=attrs.get("project_id"), stack_root=attrs.get("stack_root")
+            project_id=attrs.get("project_id"),
+            stack_root=attrs.get("stack_root"),
+            source_root=attrs.get("source_root"),
         )
         if self.instance:
             query = query.exclude(id=self.instance.id)
         if query.exists():
             raise serializers.ValidationError(
-                "Code path config already exists with this project and stack trace root"
+                "Code path config already exists with this project, stack trace root, and source root"
             )
         return attrs
 

src/sentry/integrations/api/endpoints/organization_code_mappings_bulk.py

@@ -256,11 +256,9 @@ def post(self, request: Request, organization: Organization) -> Response:
                         config = RepositoryProjectPathConfig.objects.select_for_update().get(
                             project=project,
                             stack_root=mapping["stack_root"],
+                            source_root=mapping["source_root"],
                         )
-                        for key, value in {
-                            **defaults,
-                            "source_root": mapping["source_root"],
-                        }.items():
+                        for key, value in defaults.items():
                             setattr(config, key, value)
                         created = False
                     except RepositoryProjectPathConfig.DoesNotExist:

src/sentry/integrations/models/repository_project_path_config.py

@@ -37,7 +37,7 @@ class RepositoryProjectPathConfig(DefaultFieldsModelExisting):
     class Meta:
         app_label = "sentry"
         db_table = "sentry_repositoryprojectpathconfig"
-        unique_together = (("project", "stack_root"),)
+        unique_together = (("project", "stack_root", "source_root"),)
 
     def __repr__(self) -> str:
         return (

src/sentry/issues/auto_source_code_config/code_mapping.py

@@ -348,12 +348,12 @@ def create_code_mapping(
     new_code_mapping, _ = RepositoryProjectPathConfig.objects.update_or_create(
         project=project,
         stack_root=code_mapping.stacktrace_root,
+        source_root=code_mapping.source_path,
         defaults={
             "repository": repository,
             "organization_id": organization.id,
             "integration_id": installation.model.id,
             "organization_integration_id": installation.org_integration.id,
-            "source_root": code_mapping.source_path,
             "default_branch": code_mapping.repo.branch,
             # This function is called from the UI, thus, we know that the code mapping is user generated
             "automatically_generated": False,

src/sentry/issues/auto_source_code_config/task.py

@@ -238,12 +238,12 @@ def create_code_mapping(
         _, created = RepositoryProjectPathConfig.objects.get_or_create(
             project=project,
             stack_root=code_mapping.stacktrace_root,
+            source_root=code_mapping.source_path,
             defaults={
                 "repository": repository,
                 "organization_integration_id": org_integration.id,
                 "integration_id": org_integration.integration_id,
                 "organization_id": org_integration.organization_id,
-                "source_root": code_mapping.source_path,
                 "default_branch": code_mapping.repo.branch,
                 "automatically_generated": True,
             },

src/sentry/migrations/1058_change_code_mapping_unique_constraint.py

@@ -0,0 +1,49 @@
+# Generated by Django 5.2.12 on 2026-03-27 11:40
+
+from django.db import migrations, models
+
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+    # This flag is used to mark that a migration shouldn't be automatically run in production.
+    # This should only be used for operations where it's safe to run the migration after your
+    # code has deployed. So this should not be used for most operations that alter the schema
+    # of a table.
+    # Here are some things that make sense to mark as post deployment:
+    # - Large data migrations. Typically we want these to be run manually so that they can be
+    #   monitored and not block the deploy for a long period of time while they run.
+    # - Adding indexes to large tables. Since this can take a long time, we'd generally prefer to
+    #   run this outside deployments so that we don't block them. Note that while adding an index
+    #   is a schema change, it's completely safe to run the operation after the code has deployed.
+    # Once deployed, run these manually via: https://develop.sentry.dev/database-migrations/#migration-deployment
+
+    is_post_deployment = False
+
+    dependencies = [
+        ("sentry", "1057_drop_legacy_alert_rule_tables"),
+    ]
+
+    operations = [
+        migrations.SeparateDatabaseAndState(
+            database_operations=[
+                migrations.AddConstraint(
+                    model_name="repositoryprojectpathconfig",
+                    constraint=models.UniqueConstraint(
+                        fields=["project", "stack_root", "source_root"],
+                        name="sentry_repositoryproject_project_id_stack_root_so_c371dfa7_uniq",
+                    ),
+                ),
+                migrations.AlterUniqueTogether(
+                    name="repositoryprojectpathconfig",
+                    unique_together=set(),
+                ),
+            ],
+            state_operations=[
+                migrations.AlterUniqueTogether(
+                    name="repositoryprojectpathconfig",
+                    unique_together={("project", "stack_root", "source_root")},
+                ),
+            ],
+        ),
+    ]

tests/sentry/api/endpoints/issues/test_organization_derive_code_mappings.py

@@ -321,7 +321,12 @@ def test_post_existing_code_mapping(self) -> None:
         response = self.client.post(self.url, data=config_data, format="json")
         assert response.status_code == 201, response.content
 
-        new_code_mapping = RepositoryProjectPathConfig.objects.get(
+        # Both mappings should coexist: the original and the newly derived one
+        mappings = RepositoryProjectPathConfig.objects.filter(
             project=self.project, stack_root="/stack/root"
         )
-        assert new_code_mapping.source_root == "/source/root"
+        assert mappings.count() == 2
+        assert set(mappings.values_list("source_root", flat=True)) == {
+            "/source/root/wrong",
+            "/source/root",
+        }

tests/sentry/integrations/api/endpoints/test_organization_code_mappings.py

@@ -329,7 +329,7 @@ def test_validate_path_conflict(self) -> None:
         assert response.status_code == 400
         assert response.data == {
             "nonFieldErrors": [
-                "Code path config already exists with this project and stack trace root"
+                "Code path config already exists with this project, stack trace root, and source root"
             ]
         }
 

tests/sentry/integrations/api/endpoints/test_organization_code_mappings_bulk.py

@@ -96,7 +96,8 @@ def test_update_existing_mapping(self) -> None:
             project=self.project1,
             repo=self.repo1,
             stack_root="com/example/maps",
-            source_root="old/source/root",
+            source_root="modules/maps/src/main/java/com/example/maps",
+            default_branch="old-branch",
         )
 
         response = self.make_post(
@@ -114,24 +115,26 @@ def test_update_existing_mapping(self) -> None:
         assert response.data["updated"] == 1
 
         config = RepositoryProjectPathConfig.objects.get(
-            project=self.project1, stack_root="com/example/maps"
+            project=self.project1,
+            stack_root="com/example/maps",
+            source_root="modules/maps/src/main/java/com/example/maps",
         )
-        assert config.source_root == "modules/maps/src/main/java/com/example/maps"
+        assert config.default_branch == "main"
 
     def test_mixed_create_and_update(self) -> None:
         self.create_code_mapping(
             project=self.project1,
             repo=self.repo1,
             stack_root="com/example/existing",
-            source_root="old/path",
+            source_root="existing/path",
         )
 
         response = self.make_post(
             {
                 "mappings": [
                     {
                         "stackRoot": "com/example/existing",
-                        "sourceRoot": "new/path",
+                        "sourceRoot": "existing/path",
                     },
                     {
                         "stackRoot": "com/example/new",
@@ -440,7 +443,7 @@ def test_repo_from_other_org_returns_404(self) -> None:
         response = self.make_post({"repository": "other-org/other-repo"})
         assert response.status_code == 404
 
-    def test_duplicate_stack_roots_in_request_last_wins(self) -> None:
+    def test_same_stack_root_different_source_roots_creates_both(self) -> None:
         response = self.make_post(
             {
                 "mappings": [
@@ -456,13 +459,17 @@ def test_duplicate_stack_roots_in_request_last_wins(self) -> None:
             }
         )
         assert response.status_code == 200, response.content
-        assert response.data["created"] == 1
-        assert response.data["updated"] == 1
+        assert response.data["created"] == 2
+        assert response.data["updated"] == 0
 
-        config = RepositoryProjectPathConfig.objects.get(
+        configs = RepositoryProjectPathConfig.objects.filter(
             project=self.project1, stack_root="com/example/maps"
         )
-        assert config.source_root == "second/source/root"
+        assert configs.count() == 2
+        assert set(configs.values_list("source_root", flat=True)) == {
+            "first/source/root",
+            "second/source/root",
+        }
 
     def test_multiple_repos_same_name_returns_409(self) -> None:
         # Intentionally use Repository.objects.create since create_repo uses