Add try support via GitHub action

.github/workflows/main.yml

@@ -1,35 +1,34 @@
 name: Main
 
 on:
-  push:
-    # Run the entire pipeline for 'master' even though the merge queue already runs checks
-    # for every change. This just offers an extra layer of testing and covers the case of
-    # random force pushes.
-    branches: ["master", "try"]
-  pull_request:
-    types: ['opened', 'synchronize']
-    branches: ["**"]
-  merge_group:
-    types: [checks_requested]
-  workflow_dispatch:
+  workflow_call:
+    inputs:
+      platform:
+        required: true
+        type: string
+      layout:
+        required: true
+        type: string
 
 jobs:
   decision:
     name: Decision
     runs-on: ubuntu-20.04
     outputs:
       skipped: ${{ steps.skipDecision.outputs.result }}
-      platforms: ${{ steps.platformDecision.outputs.result }}
+      platform: ${{ steps.platformDecision.outputs.result }}
+      layout-engine: ${{ steps.layoutEngineDecision.outputs.result }}
+      unit-tests: ${{ steps.unitTestDecision.outputs.result }}
     steps:
-      - name: Skip Decision
+      - name: Skip Duplicates Decision
         id: skipDecision
         uses: actions/github-script@v6
         with:
           result-encoding: string
           script: |
             // Never skip workflow runs for pull requests or merge groups, which might
             // need to actually run / retry WPT tests.
-            if (context.eventName == "pull_request" || context.eventName == "merge_group") {
+            if (context.eventName == "pull_request" || context.eventName == "merge_group" || context.eventName == "workflow_run") {
               return "run";
             }
             // Skip the run if an identical run already exists. This helps to avoid running
@@ -51,40 +50,63 @@ jobs:
         with:
           result-encoding: string
           script: |
+            if (context.eventName == "workflow_call" && "${{ inputs.platform }}" != "") {
+              return "${{ inputs.platform }}";
+            }
             if ("${{ steps.skipDecision.outputs.result }}" == "skip") {
               return "none";
             }
             if (context.eventName == "push" || context.eventName == "merge_group") {
               return "all";
             }
             return "linux"
+      - name: Layout Engine Decision
+        id: layoutEngineDecision
+        uses: actions/github-script@v6
+        with:
+          result-encoding: string
+          script: |
+            if (context.eventName == "workflow_call") {
+              return "${{ inputs.layout }}";
+            }
+            if (context.eventName == "push" || context.eventName == "merge_group") {
+              return "all";
+            }
+            return "none";
+      - name: Unit Test Decision
+        id: unitTestDecision
+        uses: actions/github-script@v6
+        with:
+          result-encoding: string
+          script: |
+            return ['push', 'merge_group', 'workflow_call'].includes(context.eventName);
 
 
   build-win:
     name: Windows
     needs: ["decision"]
-    if: ${{ needs.decision.outputs.platforms == 'all' }}
+    if: ${{ contains(fromJson('["windows", "all"]'), needs.decision.outputs.platform) }}
     uses: ./.github/workflows/windows.yml
     with:
       unit-tests: true
 
   build-mac:
     name: Mac
     needs: ["decision"]
-    if: ${{ needs.decision.outputs.platforms == 'all' }}
+    if: ${{ contains(fromJson('["macos", "all"]'), needs.decision.outputs.platform) }}
     uses: ./.github/workflows/mac.yml
     with:
       unit-tests: true
 
   build-linux:
     name: Linux
     needs: ["decision"]
-    if: ${{ needs.decision.outputs.platforms == 'all' || needs.decision.outputs.platforms == 'linux' }}
+    if: ${{ contains(fromJson('["linux", "all"]'), needs.decision.outputs.platform) }}
     uses: ./.github/workflows/linux.yml
     with:
       wpt: 'test'
-      layout: ${{ (github.event_name == 'push' || github.event_name == 'merge_group') && 'all' || 'none' }}
-      unit-tests: ${{ github.event_name == 'push' || github.event_name == 'merge_group' }}
+      layout: ${{ needs.decision.outputs.layout-engine }}
+      unit-tests: ${{ needs.decision.outputs.unit-tests }}
 
   build-result:
     name: Result

.github/workflows/run-workflow-on-comment.yml

@@ -0,0 +1,56 @@
+on: issue_comment
+
+jobs:
+  parse-comment:
+    name: PR Comment
+    if: ${{ github.event.issue.pull_request }}
+    runs-on: ubuntu-latest
+    outputs:
+      configuration: ${{ steps.configuration.outputs.result }}
+    steps:
+      - uses: actions/github-script@v6
+        id: configuration
+        with:
+          script: |
+            let result = await github.rest.repos.getCollaboratorPermissionLevel({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              username: "${{ github.event.sender.login }}"
+            });
+            if (!result.data.user.permissions.push) {
+              return { try: false };
+            }
+
+            let tokens = "${{ github.event.comment.body }}".split(" ");
+            console.log(tokens);
+            let tagIndex = tokens.indexOf("@bors-servo");
+            if (tagIndex == -1 || tagIndex + 1 >= tokens.length) {
+              return { try: false };
+            }
+
+            let tryString = tokens[tagIndex + 1];
+            console.log(tryString);
+            if (tryString == "try") {
+              return { try: true, platform: 'all', layout: 'all' };
+            } else if (tryString == "try=wpt") {
+              return { try: true, platform: 'linux', layout: '2013' };
+            } else if (tryString == "try=wpt-2020") {
+              return { try: true, platform: 'linux', layout: '2020' };
+            } else if (tryString == "try=linux") {
+              return { try: true, platform: 'linux', layout: 'none' };
+            } else if (tryString == "try=mac") {
+              return { try: true, platform: 'macos', layout: 'none' };
+            } else if (tryString == "try=windows") {
+              return { try: true, platform: 'windows', layout: 'none' };
+            }
+            return { try: false };
+
+  run-try:
+    name: Run Try
+    needs: ["parse-comment"]
+    if: ${{ fromJson(needs.parse-comment.outputs.configuration).try}}
+    uses: ./.github/workflows/main.yml
+    with:
+      platform: ${{ fromJson(needs.parse-comment.outputs.configuration).platform }}
+      layout: ${{ fromJson(needs.parse-comment.outputs.configuration).layout }}
+