Add try support via GitHub action

.github/workflows/main.yml

@@ -1,90 +1,86 @@
 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 }}
+      configuration: ${{ steps.configuration.outputs.result }}
     steps:
-      - name: Skip Decision
-        id: skipDecision
+      - name: Configuration
+        id: configuration
         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") {
-              return "run";
+            if (!['pull_request', 'merge_group', 'workflow_run'].includes(context.eventName)) {
+              // Skip the run if an identical run already exists. This helps to avoid running
+              // the workflow over and over again for the same commit hash.
+              if ((await github.rest.actions.listWorkflowRuns({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                workflow_id: "main.yml",
+                head_sha: context.sha,
+                status: "success",
+              })).data.workflow_runs.length > 0) {
+                console.log("Skipping workflow, because of duplicate job.");
+                return { platform: "none" };
+              }
             }
-            // Skip the run if an identical run already exists. This helps to avoid running
-            // the workflow over and over again for the same commit hash.
-            if ((await github.rest.actions.listWorkflowRuns({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              workflow_id: "main.yml",
-              head_sha: context.sha,
-              status: "success",
-            })).data.workflow_runs.length > 0) {
-              return "skip"
-            } else {
-              return "run"
-            }
-      - name: Platform Decision
-        id: platformDecision
-        uses: actions/github-script@v6
-        with:
-          result-encoding: string
-          script: |
-            if ("${{ steps.skipDecision.outputs.result }}" == "skip") {
-              return "none";
-            }
-            if (context.eventName == "push" || context.eventName == "merge_group") {
-              return "all";
-            }
-            return "linux"
 
+            let platform = "linux";
+            let layout = "none";
+            if (context.eventName == "workflow_call") {
+              platform = "${{ inputs.platform }}";
+              layout = "${{ inputs.layout }}";
+            } else if (["push", "merge_group"].includes(context.eventName)) {
+              platform = "all";
+              layout = "all";
+            }
+            let returnValue =  {
+              platform,
+              layout,
+              unit_tests: ['push', 'merge_group', 'workflow_call'].includes(context.eventName)
+            };
+            console.log("Using configuration: " + JSON.stringify(returnValue));
+            return returnValue;
 
   build-win:
     name: Windows
     needs: ["decision"]
-    if: ${{ needs.decision.outputs.platforms == 'all' }}
+    if: ${{ contains(fromJson('["windows", "all"]'), fromJson(needs.decision.outputs.configuration).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"]'), fromJson(needs.decision.outputs.configuration).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"]'), fromJson(needs.decision.outputs.configuration).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: ${{ fromJson(needs.decision.outputs.configuration).layout }}
+      unit-tests: ${{ fromJson(needs.decision.outputs.configuration).unit_tests }}
 
   build-result:
     name: Result
@@ -99,7 +95,7 @@ jobs:
 
     steps:
       - name: Mark skipped jobs as successful
-        if: ${{ needs.decision.outputs.skipped == 'skip' }}
+        if: ${{ fromJson(needs.decision.outputs.configuration).platform == 'none' }}
         run: exit 0
       - name: Mark the job as successful
         if: ${{ !contains(join(needs.*.result, ','), 'failure') && !contains(join(needs.*.result, ','), 'cancelled') }}

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

@@ -0,0 +1,64 @@
+on: issue_comment
+name: Try
+
+jobs:
+  parse-comment:
+    name: Process Comment
+    if: ${{ github.event.issue.pull_request }}
+    runs-on: ubuntu-latest
+    outputs:
+      configuration: ${{ steps.configuration.outputs.result }}
+    steps:
+      - uses: actions/github-script@v6
+        id: configuration
+        with:
+          script: |
+            let tokens = "${{ 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("Found try string: '" + tryString + "'");
+            let returnValue = { try: false };
+            if (tryString == "try") {
+              returnValue = { try: true, platform: 'all', layout: 'all' };
+            } else if (tryString == "try=wpt") {
+              returnValue = { try: true, platform: 'linux', layout: '2013' };
+            } else if (tryString == "try=wpt-2020") {
+              returnValue = { try: true, platform: 'linux', layout: '2020' };
+            } else if (tryString == "try=linux") {
+              returnValue = { try: true, platform: 'linux', layout: 'none' };
+            } else if (tryString == "try=mac") {
+              returnValue = { try: true, platform: 'macos', layout: 'none' };
+            } else if (tryString == "try=windows") {
+              returnValue = { try: true, platform: 'windows', layout: 'none' };
+            }
+
+            if (returnValue.try) {
+              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) {
+                console.log("User does not have permission to try.");
+                return { try: false };
+              }
+            }
+
+            console.log("Triggering try with configuration: " + JSON.stringify(returnValue));
+            return returnValue;
+
+
+  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 }}
+