Create backport-base.yml

.github/workflows/backport-base.yml

@@ -0,0 +1,228 @@
+# Based on: https://github.com/dotnet/arcade/blob/main/.github/workflows/backport-base.yml
+# Ref: https://github.com/dotnet/arcade/blob/7cd1cae2edfb3895f5f0ee577131e0214ed8af1a/.github/workflows/backport-base.yml
+
+on:
+  workflow_call:
+    inputs:
+      pr_title_template:
+        description: 'The template used for the PR title. Special placeholder tokens that will be replaced with a value: %target_branch%, %source_pr_title%, %source_pr_number%, %cc_users%.'
+        required: false
+        type: string
+        default: '[%target_branch%] %source_pr_title%'
+      pr_description_template:
+        description: 'The template used for the PR description. Special placeholder tokens that will be replaced with a value: %target_branch%, %source_pr_title%, %source_pr_number%, %cc_users%.'
+        required: false
+        type: string
+        default: |
+          Backport of #%source_pr_number% to %target_branch%
+
+          /cc %cc_users%
+      repository_owners:
+        description: 'A comma-separated list of repository owners where the workflow will run. Defaults to "dotnet,microsoft".'
+        required: false
+        type: string
+        default: 'dotnet,microsoft'
+
+jobs:
+  # Add cleanup job
+  # cleanup:
+  #  uses: dotnet/arcade/.github/workflows/scheduled-action-cleanup-base.yml@main
+  #  with:
+  #    repository_owners: ${{ inputs.repository_owners }}
+
+  run_backport:
+    if: ${{ contains(format('{0},', inputs.repository_owners), format('{0},', github.repository_owner)) && github.event.issue.pull_request != '' && contains(github.event.comment.body, '/backport to') }}
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      issues: write
+      pull-requests: write
+    steps:
+    - name: Extract backport target branch
+      uses: actions/github-script@v7
+      id: target-branch-extractor
+      with:
+        result-encoding: string
+        script: |
+          if (context.eventName !== "issue_comment") throw "Error: This action only works on issue_comment events.";
+
+          // extract the target branch name from the trigger phrase containing these characters: a-z, A-Z, digits, forward slash, dot, hyphen, underscore
+          const regex = /^\/backport to ([a-zA-Z\d\/\.\-\_]+)/;
+          target_branch = regex.exec(context.payload.comment.body);
+          if (target_branch == null) throw "Error: No backport branch found in the trigger phrase.";
+
+          return target_branch[1];
+    - name: Unlock comments if PR is locked
+      uses: actions/github-script@v7
+      if: ${{ github.event.issue.locked == true }}
+      with:
+        script: |
+          console.log(`Unlocking locked PR #${context.issue.number}.`);
+          await github.rest.issues.unlock({
+            issue_number: context.issue.number,
+            owner: context.repo.owner,
+            repo: context.repo.repo,
+          });
+    - name: Post backport started comment to pull request
+      uses: actions/github-script@v7
+      with:
+        script: |
+          const target_branch = '${{ steps.target-branch-extractor.outputs.result }}';
+          const backport_start_body = `Started backporting to ${target_branch}: https://github.com/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`;
+          await github.rest.issues.createComment({
+            issue_number: context.issue.number,
+            owner: context.repo.owner,
+            repo: context.repo.repo,
+            body: backport_start_body
+          });
+    - name: Checkout repo
+      uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+    - name: Run backport
+      uses: actions/github-script@v7
+      env:
+        BACKPORT_PR_TITLE_TEMPLATE: ${{ inputs.pr_title_template }}
+        BACKPORT_PR_DESCRIPTION_TEMPLATE: ${{ inputs.pr_description_template }}
+      with:
+        script: |
+          const target_branch = '${{ steps.target-branch-extractor.outputs.result }}';
+          const repo_owner = context.payload.repository.owner.login;
+          const repo_name = context.payload.repository.name;
+          const pr_number = context.payload.issue.number;
+          const comment_user = context.payload.comment.user.login;
+
+          try {
+            // verify the comment user is a repo collaborator
+            try {
+              await github.rest.repos.checkCollaborator({
+                owner: repo_owner,
+                repo: repo_name,
+                username: comment_user
+              });
+              console.log(`Verified ${comment_user} is a repo collaborator.`);
+            } catch (error) {
+              console.log(error);
+              throw new Error(`Error: @${comment_user} is not a repo collaborator, backporting is not allowed. If you're a collaborator please make sure your ${repo_owner} team membership visibility is set to Public on https://github.com/orgs/${repo_owner}/people?query=${comment_user}`);
+            }
+
+            try { await exec.exec(`git ls-remote --exit-code --heads origin ${target_branch}`) } catch { throw new Error(`Error: The specified backport target branch ${target_branch} wasn't found in the repo.`); }
+            console.log(`Backport target branch: ${target_branch}`);
+
+            console.log("Applying backport patch");
+
+            await exec.exec(`git checkout ${target_branch}`);
+            await exec.exec(`git clean -xdff`);
+
+            // configure git
+            await exec.exec(`git config user.name "github-actions"`);
+            await exec.exec(`git config user.email "[email protected]"`);
+
+            // create temporary backport branch
+            const temp_branch = `backport/pr-${pr_number}-to-${target_branch}`;
+            await exec.exec(`git checkout -b ${temp_branch}`);
+
+            // skip opening PR if the branch already exists on the origin remote since that means it was opened
+            // by an earlier backport and force pushing to the branch updates the existing PR
+            let should_open_pull_request = true;
+            try {
+              await exec.exec(`git ls-remote --exit-code --heads origin ${temp_branch}`);
+              should_open_pull_request = false;
+            } catch { }
+
+            // download and apply patch
+            await exec.exec(`curl -sSL "${context.payload.issue.pull_request.patch_url}" --output changes.patch`);
+
+            const git_am_command = "git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patch";
+            let git_am_output = `$ ${git_am_command}\n\n`;
+            let git_am_failed = false;
+            try {
+              await exec.exec(git_am_command, [], {
+                listeners: {
+                  stdout: function stdout(data) { git_am_output += data; },
+                  stderr: function stderr(data) { git_am_output += data; }
+                }
+              });
+            } catch (error) {
+              git_am_output += error;
+              git_am_failed = true;
+            }
+
+            if (git_am_failed) {
+              const git_am_failed_body = `@${context.payload.comment.user.login} backporting to ${target_branch} failed, the patch most likely resulted in conflicts:\n\n\`\`\`shell\n${git_am_output}\n\`\`\`\n\nPlease backport manually!`;
+              await github.rest.issues.createComment({
+                owner: repo_owner,
+                repo: repo_name,
+                issue_number: pr_number,
+                body: git_am_failed_body
+              });
+              throw new Error("Error: git am failed, most likely due to a merge conflict.", false);
+            }
+            else {
+              // push the temp branch to the repository
+              await exec.exec(`git push --force --set-upstream origin HEAD:${temp_branch}`);
+            }
+
+            if (!should_open_pull_request) {
+              console.log("Backport temp branch already exists, skipping opening a PR.");
+              return;
+            }
+
+            // prepare the GitHub PR details
+
+            // get users to cc (append PR author if different from user who issued the backport command)
+            let cc_users = `@${comment_user}`;
+            if (comment_user != context.payload.issue.user.login) cc_users += ` @${context.payload.issue.user.login}`;
+
+            // replace the special placeholder tokens with values
+            const { BACKPORT_PR_TITLE_TEMPLATE, BACKPORT_PR_DESCRIPTION_TEMPLATE } = process.env
+
+            const backport_pr_title = BACKPORT_PR_TITLE_TEMPLATE
+              .replace(/%target_branch%/g, target_branch)
+              .replace(/%source_pr_title%/g, context.payload.issue.title)
+              .replace(/%source_pr_number%/g, context.payload.issue.number)
+              .replace(/%cc_users%/g, cc_users);
+
+            const backport_pr_description = BACKPORT_PR_DESCRIPTION_TEMPLATE
+              .replace(/%target_branch%/g, target_branch)
+              .replace(/%source_pr_title%/g, context.payload.issue.title)
+              .replace(/%source_pr_number%/g, context.payload.issue.number)
+              .replace(/%cc_users%/g, cc_users);
+
+            // open the GitHub PR
+            await github.rest.pulls.create({
+              owner: repo_owner,
+              repo: repo_name,
+              title: backport_pr_title,
+              body: backport_pr_description,
+              head: temp_branch,
+              base: target_branch
+            });
+
+            console.log("Successfully opened the GitHub PR.");
+          } catch (error) {
+
+            core.setFailed(error);
+
+            // post failure to GitHub comment
+            const unknown_error_body = `@${comment_user} an error occurred while backporting to ${target_branch}, please check the run log for details!\n\n${error.message}`;
+            await github.rest.issues.createComment({
+              owner: repo_owner,
+              repo: repo_name,
+              issue_number: pr_number,
+              body: unknown_error_body
+            });
+          }
+
+    - name: Re-lock PR comments
+      uses: actions/github-script@v7
+      if: ${{ github.event.issue.locked == true && (success() || failure()) }}
+      with:
+        script: |
+          console.log(`Locking previously locked PR #${context.issue.number} again.`);
+          await github.rest.issues.lock({
+            issue_number: context.issue.number,
+            owner: context.repo.owner,
+            repo: context.repo.repo,
+            lock_reason: "resolved"
+          });