Add support to query a CL's branch to gerrit recipe module

Bug: 740456
Change-Id: Ic4f3c1f046cfa025d8e60172ee58e2b2e1b76ee6
Reviewed-on: https://chromium-review.googlesource.com/565560
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Aaron Gable <agable@chromium.org>

recipes/README.recipes.md

@@ -312,7 +312,18 @@ Create a new branch from given project and commit
 Returns:
   the ref of the branch created
 
-— **def [get\_changes](/recipes/recipe_modules/gerrit/api.py#66)(self, host, query_params, start=None, limit=None, \*\*kwargs):**
+— **def [get\_change\_destination\_branch](/recipes/recipe_modules/gerrit/api.py#68)(self, host, change, \*\*kwargs):**
+
+Get the upstream branch for a given CL.
+
+Args:
+  host: Gerrit host to query.
+  change: The change number.
+
+Returns:
+  the name of the branch
+
+— **def [get\_changes](/recipes/recipe_modules/gerrit/api.py#93)(self, host, query_params, start=None, limit=None, \*\*kwargs):**
 
 Query changes for the given host.
 
@@ -327,7 +338,7 @@ Returns:
   A list of change dicts as documented here:
       https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#list-changes
 
-— **def [get\_gerrit\_branch](/recipes/recipe_modules/gerrit/api.py#47)(self, host, project, branch, \*\*kwargs):**
+— **def [get\_gerrit\_branch](/recipes/recipe_modules/gerrit/api.py#49)(self, host, project, branch, \*\*kwargs):**
 
 Get a branch from given project and commit
 

recipes/recipe_modules/gerrit/api.py

@@ -44,6 +44,8 @@ class GerritApi(recipe_api.RecipeApi):
     ref = step_result.json.output.get('ref')
     return ref
 
+  # TODO(machenbach): Rename to get_revision? And maybe above to
+  # create_ref?
   def get_gerrit_branch(self, host, project, branch, **kwargs):
     """
     Get a branch from given project and commit
@@ -63,6 +65,31 @@ class GerritApi(recipe_api.RecipeApi):
     revision = step_result.json.output.get('revision')
     return revision
 
+  def get_change_destination_branch(self, host, change, **kwargs):
+    """
+    Get the upstream branch for a given CL.
+
+    Args:
+      host: Gerrit host to query.
+      change: The change number.
+
+    Returns:
+      the name of the branch
+    """
+    assert int(change)
+    kwargs.setdefault('name', 'get_change_destination_branch')
+    changes = self.get_changes(
+        host,
+        [('change', change)],
+        limit=1,
+        **kwargs
+    )
+    if not changes or 'branch' not in changes[0]:
+      self.m.step.active_result.presentation.status = self.m.step.EXCEPTION
+      raise self.m.step.InfraFailure(
+          'Error quering for branch of CL %s' % change)
+    return changes[0]['branch']
+
   def get_changes(self, host, query_params, start=None, limit=None, **kwargs):
     """
     Query changes for the given host.
@@ -91,7 +118,7 @@ class GerritApi(recipe_api.RecipeApi):
       args += ['-p', '%s=%s' % (k, v)]
 
     return self(
-        'changes',
+        kwargs.pop('name', 'changes'),
         args,
         step_test_data=lambda: self.test_api.get_changes_response_data(),
         **kwargs

recipes/recipe_modules/gerrit/examples/full.expected/basic.json

@@ -100,9 +100,72 @@
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_PACKAGE_REPO[depot_tools]/gerrit_client.py",
+      "changes",
+      "--host",
+      "https://chromium-review.googlesource.com",
+      "--json_file",
+      "/path/to/tmp/json",
+      "--limit",
+      "1",
+      "-p",
+      "change=123"
+    ],
+    "env": {
+      "PATH": "<PATH>:RECIPE_PACKAGE_REPO[depot_tools]"
+    },
+    "infra_step": true,
+    "name": "gerrit get_change_destination_branch",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@json.output@[@@@",
+      "@@@STEP_LOG_LINE@json.output@  {@@@",
+      "@@@STEP_LOG_LINE@json.output@    \"_number\": \"91827\", @@@",
+      "@@@STEP_LOG_LINE@json.output@    \"branch\": \"master\", @@@",
+      "@@@STEP_LOG_LINE@json.output@    \"change_id\": \"Ideadbeef\", @@@",
+      "@@@STEP_LOG_LINE@json.output@    \"created\": \"2017-01-30 13:11:20.000000000\", @@@",
+      "@@@STEP_LOG_LINE@json.output@    \"has_review_started\": false, @@@",
+      "@@@STEP_LOG_LINE@json.output@    \"project\": \"chromium/src\", @@@",
+      "@@@STEP_LOG_LINE@json.output@    \"status\": \"NEW\", @@@",
+      "@@@STEP_LOG_LINE@json.output@    \"subject\": \"Change title\"@@@",
+      "@@@STEP_LOG_LINE@json.output@  }@@@",
+      "@@@STEP_LOG_LINE@json.output@]@@@",
+      "@@@STEP_LOG_END@json.output@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_PACKAGE_REPO[depot_tools]/gerrit_client.py",
+      "changes",
+      "--host",
+      "https://chromium-review.googlesource.com",
+      "--json_file",
+      "/path/to/tmp/json",
+      "--limit",
+      "1",
+      "-p",
+      "change=123"
+    ],
+    "env": {
+      "PATH": "<PATH>:RECIPE_PACKAGE_REPO[depot_tools]"
+    },
+    "infra_step": true,
+    "name": "gerrit missing_cl",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@json.output@[]@@@",
+      "@@@STEP_LOG_END@json.output@@@",
+      "@@@STEP_EXCEPTION@@@"
+    ]
+  },
   {
     "name": "$result",
+    "reason": "Error quering for branch of CL 123",
     "recipe_result": null,
-    "status_code": 0
+    "status_code": 1
   }
 ]
\ No newline at end of file

recipes/recipe_modules/gerrit/examples/full.py

@@ -32,6 +32,12 @@ def RunSteps(api):
       limit=1,
   )
 
+  api.gerrit.get_change_destination_branch(host, change=123)
+
+  api.gerrit.get_change_destination_branch(
+      host, change=123, name='missing_cl')
+
+
 def GenTests(api):
   yield (
       api.test('basic')
@@ -43,4 +49,8 @@ def GenTests(api):
           'gerrit get_gerrit_branch',
           api.gerrit.make_gerrit_get_branch_response_data()
       )
+      + api.step_data(
+          'gerrit missing_cl',
+          api.gerrit.get_empty_changes_response_data()
+      )
   )

recipes/recipe_modules/gerrit/test_api.py

@@ -38,3 +38,6 @@ class GerritTestApi(recipe_test_api.RecipeTestApi):
         'subject': 'Change title',
       },
     ])
+
+  def get_empty_changes_response_data(self):
+    return self._make_gerrit_response_json([])