Bug 1508382: [taskgraph] Verify that the specifed sparse profile exists; r=gps

Differential Revision: https://phabricator.services.mozilla.com/D12449

--HG--
extra : moz-landing-system : lando

taskcluster/taskgraph/transforms/job/toolchain.py

@@ -161,8 +161,8 @@ def docker_worker_toolchain(config, job, taskdesc):
 
     sparse_profile = []
     if run.get('sparse-profile'):
-        sparse_profile = ['--sparse-profile',
-                          'build/sparse-profiles/{}'.format(run['sparse-profile'])]
+        sparse_profile = ['--sparse-profile=build/sparse-profiles/{}'
+                          .format(run['sparse-profile'])]
 
     worker['command'] = [
         '{workdir}/bin/run-task'.format(**run),

taskcluster/taskgraph/transforms/task.py

@@ -1914,6 +1914,16 @@ def check_run_task_caches(config, tasks):
                     break
 
                 if arg.startswith('--sparse-profile'):
+                    if '=' not in arg:
+                        raise Exception(
+                            '{} is specifying `--sparse-profile` to run-task as two arguments. '
+                            'Unable to determine if the sparse profile exists.'.format(
+                                task['label']))
+                    _, sparse_profile = arg.split('=', 1)
+                    if not os.path.exists(os.path.join(GECKO, sparse_profile)):
+                        raise Exception(
+                            '{} is using non-existant sparse profile {}.'.format(
+                                task['label'], sparse_profile))
                     require_sparse_cache = True
                     break