API: support rebuilding external version builds with build create end…

…point (#11407)

* API: support rebuilding external version builds with build create endpoint

On the old dashboard, we are using a hidden form on two views to retry
builds, but the API is a more consistent way to do this. The feature
this endpoint is missing that BuildTriggerMixin has is retrying a build
for a version using the last build commit.

What is different in this method is that we don't give the user an error
if the build isn't the latest build for a version. To the user, this
detail shouldn't matter and this endpoint instead automatically uses the last
build to get the commit to start the new build.

* Add basic test case for external build trigger

* Refactor tests

* Lint

readthedocs/api/v3/tests/test_builds.py

@@ -3,6 +3,7 @@
 from django.test import override_settings
 from django.urls import reverse
 
+from readthedocs.builds.constants import EXTERNAL
 from readthedocs.subscriptions.constants import TYPE_CONCURRENT_BUILDS
 from readthedocs.subscriptions.products import RTDProductFeature
 
@@ -82,6 +83,37 @@ def test_projects_versions_builds_list_post(self):
             self._get_response_dict("projects-versions-builds-list_POST"),
         )
 
+    def test_external_version_projects_versions_builds_list_post(self):
+        """Build starts using last commit against external version."""
+        self.version.type = EXTERNAL
+        self.build.commit = "d4e5f6"
+        self.version.save()
+        self.build.save()
+        url = reverse(
+            "projects-versions-builds-list",
+            kwargs={
+                "parent_lookup_project__slug": self.project.slug,
+                "parent_lookup_version__slug": self.version.slug,
+            },
+        )
+
+        self.client.credentials(HTTP_AUTHORIZATION=f"Token {self.token.key}")
+        self.assertEqual(self.project.builds.count(), 1)
+        response = self.client.post(url)
+        self.assertEqual(response.status_code, 202)
+        self.assertEqual(self.project.builds.count(), 2)
+
+        response_json = response.json()
+        response_json["build"]["created"] = "2019-04-29T14:00:00Z"
+        expected = self._get_response_dict("projects-versions-builds-list_POST")
+        expected["build"]["commit"] = "d4e5f6"
+        expected["version"]["type"] = "external"
+        expected["version"]["urls"][
+            "documentation"
+        ] = "http://project--v1.0.external-builds.readthedocs.io/en/v1.0/"
+        expected["version"]["urls"]["vcs"] = "https://github.com/rtfd/project/pull/v1.0"
+        self.assertDictEqual(response_json, expected)
+
     def test_projects_builds_notifications_list(self):
         url = reverse(
             "projects-builds-notifications-list",

readthedocs/api/v3/views.py

@@ -369,8 +369,21 @@ def get_serializer_class(self):
     def create(self, request, **kwargs):  # pylint: disable=arguments-differ
         project = self._get_parent_project()
         version = self._get_parent_version()
-
-        _, build = trigger_build(project, version=version)
+        build_retry = None
+        commit = None
+
+        if version.is_external:
+            # We use the last build for a version here as we want to update VCS
+            # providers and need to reference the latest commit to do so.
+            build_retry = version.last_build
+            if build_retry:
+                commit = build_retry.commit
+
+        _, build = trigger_build(
+            project=project,
+            version=version,
+            commit=commit,
+        )
 
         # TODO: refactor this to be a serializer
         # BuildTriggeredSerializer(build, project, version).data

readthedocs/builds/views.py

@@ -43,6 +43,9 @@ def get_queryset(self):
         return queryset
 
 
+# TODO this class and views that extend this class can be removed when the old
+# dashboard goes away and RTD_EXT_THEME_ENABLED is removed. Instead of using a
+# hidden form on views, the new dashboard uses APIv3 to trigger new builds.
 class BuildTriggerMixin:
     @method_decorator(login_required)
     def post(self, request, project_slug):