Handles a PushRepository.DoesNotExist exception

fixes: pulp#1712

CHANGES/1712.bugfix

@@ -0,0 +1,2 @@
+Resolved an issue that caused an HTTP 500 error when attempting to push an image with the same name
+as an existing regular repository.

docs/user/guides/push-image.md

@@ -47,7 +47,8 @@ X-Frame-Options: SAMEORIGIN
 !!! note
 
     Content is pushed to a push repository type. A push repository does not support mirroring of the
-    remote content via the Pulp API.
+    remote content via the Pulp API. Trying to push a content with the same name of an existing
+    "regular" repository will fail.
 
 !!! note
 

pulp_container/app/registry_api.py

@@ -392,7 +392,16 @@ def get_dr_push(self, request, path, create=False):
 
     def create_dr(self, path, request):
         with transaction.atomic():
-            repository = serializers.ContainerPushRepositorySerializer.get_or_create({"name": path})
+            try:
+                repository = serializers.ContainerPushRepositorySerializer.get_or_create(
+                    {"name": path}
+                )
+            except models.ContainerPushRepository.DoesNotExist:
+                raise RepositoryInvalid(
+                    name=path,
+                    message='Cannot create "' + path + '" push repository, another repository with '
+                    "the same name already exists.",
+                )
             distribution = serializers.ContainerDistributionSerializer.get_or_create(
                 {"base_path": path, "name": path}, {"repository": get_url(repository)}
             )

pulp_container/tests/functional/api/test_push_content.py

@@ -27,6 +27,7 @@
 )
 
 from pulpcore.client.pulp_container import (
+    ContainerContainerRepository,
     ContentManifestsApi,
     ContentTagsApi,
     DistributionsContainerApi,
@@ -394,6 +395,26 @@ def test_push_matching_username(
         add_to_cleanup(container_namespace_api, distribution.namespace)
 
 
+def test_push_to_existing_regular_repository(
+    container_repository_api,
+    gen_object_with_cleanup,
+    local_registry,
+    registry_client,
+):
+    """
+    Test the push to an existing non-push repository.
+
+    It should fail to create a new push repository.
+    """
+    gen_object_with_cleanup(container_repository_api, ContainerContainerRepository(name="foo"))
+    image_path = f"{REGISTRY_V2_REPO_PULP}:manifest_a"
+    local_url = "foo:1.0"
+
+    registry_client.pull(image_path)
+    with pytest.raises(CalledProcessError):
+        local_registry.tag_and_push(image_path, local_url)
+
+
 class PushManifestListTestCase(PulpTestCase, rbac_base.BaseRegistryTest):
     """A test case that verifies if a container client can push manifest lists to the registry."""