Bug 1455448: Don't include `firefox` in the decision task index; r=dustin,mshal,rail,Callek a=release

The decision task is used for everything built as part of a push (for
mozilla-central, this is firefox, devedition and fennec, as well as tasks that
aren't strictly part of any product). Thus, having `firefox` encoded as part of
the decision task doesn't make sense.

This changes the route from
    index.gecko.v2.${repository.project}.latest.firefox.decision
to
    index.gecko.v2.${repository.project}.latest.taskgraph.decision
while leaving the latter for backwards compatability with tools that expect it.

Differential Revision: https://phabricator.services.mozilla.com/D996

--HG--
extra : rebase_source : c4c4691bb4633225e5e37b21982b916f76353e27
extra : source : 6ef1607a3e63250eefbda5333d61fd338c23311d

.taskcluster.yml

@@ -52,19 +52,25 @@ tasks:
             kind: 'action-callback'
 
       routes:
-        $if: 'tasks_for == "hg-push"'
-        then:
-          - "index.gecko.v2.${repository.project}.latest.firefox.decision"
-          - "index.gecko.v2.${repository.project}.revision.${push.revision}.firefox.decision"
-          - "index.gecko.v2.${repository.project}.pushlog-id.${push.pushlog_id}.decision"
+        $flatten:
           - "tc-treeherder.v2.${repository.project}.${push.revision}.${push.pushlog_id}"
-          - "notify.email.${ownerEmail}.on-failed"
-          - "notify.email.${ownerEmail}.on-exception"
-        else:
-          - "tc-treeherder.v2.${repository.project}.${push.revision}.${push.pushlog_id}"
-          - $if: 'tasks_for == "action"'
-            then: "index.gecko.v2.${repository.project}.pushlog-id.${push.pushlog_id}.actions.${ownTaskId}"
-            else: "index.gecko.v2.${repository.project}.latest.firefox.decision-${cron.job_name}"
+          - $if: 'tasks_for == "hg-push"'
+            then:
+              - "index.gecko.v2.${repository.project}.latest.taskgraph.decision"
+              - "index.gecko.v2.${repository.project}.revision.${push.revision}.taskgraph.decision"
+              - "index.gecko.v2.${repository.project}.pushlog-id.${push.pushlog_id}.decision"
+              - "notify.email.${ownerEmail}.on-failed"
+              - "notify.email.${ownerEmail}.on-exception"
+              # These are the old index routes for the decision task.
+              # They are still here so external tools that referenced them continue to work.
+              - "index.gecko.v2.${repository.project}.latest.firefox.decision"
+              - "index.gecko.v2.${repository.project}.revision.${push.revision}.firefox.decision"
+            else:
+              $if: 'tasks_for == "action"'
+              then: "index.gecko.v2.${repository.project}.pushlog-id.${push.pushlog_id}.actions.${ownTaskId}"
+              else:
+              - "index.gecko.v2.${repository.project}.latest.taskgraph.decision-${cron.job_name}"
+              - "index.gecko.v2.${repository.project}.latest.firefox.decision-${cron.job_name}"
 
       scopes:
         $if: 'tasks_for == "hg-push"'

taskcluster/taskgraph/parameters.py

@@ -188,7 +188,9 @@ def load_parameters_file(filename, strict=True):
         if filename.startswith("task-id="):
             task_id = filename.split("=")[1]
         elif filename.startswith("project="):
-            index = "gecko.v2.{}.latest.firefox.decision".format(filename.split("=")[1])
+            index = "gecko.v2.{project}.latest.firefox.decision".format(
+                project=filename.split("=")[1],
+            )
             task_id = find_task_id(index)
 
         if task_id: