Bug 1810150 - stop scheduling pull-request task graphs when there's already a...

Bug 1810150 - stop scheduling pull-request task graphs when there's already a corresponding push graph

When a PR is opened from a branch in the main repo, we used to create a
task graph for both the push event and the pull-request open or
synchronize event, associated with the same commit, and thus essentially
doing the same work twice.

With this change, we skip the pull-request graph, and rely on the push
graph to run the required checks.  This requires corresponding changes
to the mergify config to consider either of complete-pr or complete-push
as good enough to merge a PR.

.mergify.yml

 queue_rules:
   - name: default
     conditions:
-      - status-success=complete-pr
+      - or:
+        - status-success=complete-pr
+        - status-success=complete-push
 pull_request_rules:
   - name: Resolve conflict
     conditions:
@@ -12,7 +14,7 @@ pull_request_rules:
   - name: MickeyMoz - Auto Merge
     conditions:
       - author=MickeyMoz
-      - status-success=complete-pr
+      - status-success=complete-push
       - files~=^android-components/(Gecko\.kt|components/lib/publicsuffixlist/src/main/assets/publicsuffixes)
       - -files~=^(?!android-components/(Gecko\.kt|components/lib/publicsuffixlist/src/main/assets/publicsuffixes)).+$
     actions:
@@ -25,7 +27,7 @@ pull_request_rules:
   - name: L10N - Auto Merge
     conditions:
       - author~=(mozilla-l10n-automation-bot|github-actions\[bot\])
-      - status-success=complete-pr
+      - status-success=complete-push
       - files~=^(android-components|focus-android)/(.+/strings\.xml|l10n\.toml)
       - -files~=^(?!(android-components|focus-android)/(.+/strings\.xml|l10n\.toml)).+$
     actions:
@@ -38,7 +40,7 @@ pull_request_rules:
   - name: Release automation
     conditions:
       - author=github-actions[bot]
-      - status-success=complete-pr
+      - status-success=complete-push
       - files~=^android-components/(\.buildconfig\.yml|.+/NimbusGradlePlugin\.groovy|plugins/dependencies/src/main/java/(Gecko|DependenciesPlugin)\.kt|buildSrc/src/main/java/Gecko\.kt)
       - -files~=^(?!android-components/(\.buildconfig\.yml|.+/NimbusGradlePlugin\.groovy|plugins/dependencies/src/main/java/(Gecko|DependenciesPlugin)\.kt|buildSrc/src/main/java/Gecko\.kt)).+$
     actions:
@@ -52,7 +54,9 @@ pull_request_rules:
         force: false
   - name: Needs landing - Rebase
     conditions:
-      - status-success=complete-pr
+      - or:
+        - status-success=complete-pr
+        - status-success=complete-push
       - label=🛬 needs landing
       - "#approved-reviews-by>=1"
       - -draft
@@ -64,7 +68,9 @@ pull_request_rules:
         name: default
   - name: Needs landing - Squash
     conditions:
-      - status-success=complete-pr
+      - or:
+        - status-success=complete-pr
+        - status-success=complete-push
       - label=🛬 needs landing (squash)
       - "#approved-reviews-by>=1"
       - -draft

.taskcluster.yml

@@ -146,8 +146,8 @@ tasks:
               in:
                   $if: >
                       tasks_for in ["action", "cron"]
-                      || (isPullRequest && pullRequestAction in ["opened", "reopened", "synchronize"])
-                      || (tasks_for == "github-push" && head_ref[:10] != "refs/tags/" && short_head_ref != "staging.tmp" && short_head_ref != "trying.tmp" && short_head_ref[:8] != "mergify/")
+                      || (isPullRequest && pullRequestAction in ["opened", "reopened", "synchronize"] && baseRepoUrl != repoUrl)
+                      || (tasks_for == "github-push" && head_ref[:10] != "refs/tags/" && short_head_ref != "staging.tmp" && short_head_ref != "trying.tmp")
                   then:
                       $mergeDeep:
                           - $if: 'tasks_for != "action"'