Fix V3 collection list endpoint

https://pulp.plan.io/issues/8276
closes #8276

(cherry picked from commit 292d158)

CHANGES/8276.bugfix

@@ -0,0 +1 @@
+Fix V3 collection list endpoint when repository is empty

pulp_ansible/app/galaxy/v3/views.py

@@ -280,7 +280,7 @@ def get_serializer_context(self, *args, **kwargs):
         super_data = super().get_serializer_context()
         if getattr(self, "available_versions_context", None):
             super_data["available_versions"] = self.available_versions_context
-        super_data["deprecated_collections"] = self.deprecated_collections_context
+        super_data["deprecated_collections"] = getattr(self, "deprecated_collections_context", [])
         return super_data
 
     def update(self, request, *args, **kwargs):

pulp_ansible/tests/functional/cli/test_collection_upload.py

@@ -9,6 +9,7 @@
 
 from pulpcore.client.pulp_ansible import (
     DistributionsAnsibleApi,
+    PulpAnsibleGalaxyApiCollectionsApi,
     PulpAnsibleGalaxyApiV3VersionsApi,
     RemotesCollectionApi,
     RepositoriesAnsibleApi,
@@ -33,6 +34,7 @@ def setUpClass(cls):
         cls.repo_versions_api = RepositoriesAnsibleVersionsApi(cls.client)
         cls.remote_collection_api = RemotesCollectionApi(cls.client)
         cls.distributions_api = DistributionsAnsibleApi(cls.client)
+        cls.collections_v3api = PulpAnsibleGalaxyApiCollectionsApi(cls.client)
         cls.collections_versions_v3api = PulpAnsibleGalaxyApiV3VersionsApi(cls.client)
 
     def test_upload_collection(self):
@@ -88,6 +90,10 @@ def test_upload_collection_with_requires_ansible(self):
         distribution = self.distributions_api.read(created_resources[0])
 
         self.addCleanup(self.distributions_api.delete, distribution.pulp_href)
+
+        collections = self.collections_v3api.list(distribution.base_path)
+        self.assertEqual(collections.meta.count, 0)
+
         colletion_path = os.path.join(
             os.getcwd(), "pulp_ansible/tests/assets/collections/pulp-testing_asset-1.0.0.tar.gz"
         )
@@ -98,6 +104,9 @@ def test_upload_collection_with_requires_ansible(self):
         subprocess.run(cmd.split())
         wait_tasks()
 
+        collections = self.collections_v3api.list(distribution.base_path)
+        self.assertEqual(collections.meta.count, 1)
+
         repo = self.repo_api.read(repo.pulp_href)
         repo_version = self.repo_versions_api.read(repo.latest_version_href)
         self.assertEqual(repo_version.number, 1)  # We uploaded 1 collection