Adding action to generate branch for forks (#2977)

* adding action to generate branch for forks + build comment for forks

* only create/update a new branch if the trigger comment was made in a fork pr

* changing comment used to trigger build

* restrict to open PRs only

* changing trigger for testing

Author: LFDanLu

.circleci/comment.js

@@ -7,19 +7,57 @@ const octokit = new Octokit({
 run();
 
 async function run() {
+  let pr;
+  // If we aren't running on a PR commit, double check if this is a branch created for a fork. If so, we'll need to
+  // comment the build link on the fork.
   if (!process.env.CIRCLE_PULL_REQUEST) {
-    return;
+    try {
+      const commit = await octokit.git.getCommit({
+        owner: 'adobe',
+        repo: 'react-spectrum',
+        commit_sha: process.env.CIRCLE_SHA1
+      });
+
+      // Check if it is a merge commit from the github "Branch from fork action"
+      if (commit && commit.data?.parents?.length === 2 && commit.data.message.indexOf('Merge') > -1) {
+        // Unfortunately listPullRequestsAssociatedWithCommit doesn't return fork prs so have to use search api
+        // to find the fork PR the original commit lives in
+        const forkHeadCommit = commit.data.parents[1].sha;
+        const searchRes = await octokit.search.issuesAndPullRequests({
+          q: `${forkHeadCommit}+repo:adobe/react-spectrum+is:pr+is:open`
+        });
+
+        // Look for a PR that is from a fork and has a matching head commit as the current branch
+        const pullNumbers = searchRes.data.items.filter(i => i.pull_request !== undefined).map(j => j.number);
+        for (let pull_number of pullNumbers) {
+          const {data} = await octokit.pulls.get({
+            owner: 'adobe',
+            repo: 'react-spectrum',
+            pull_number
+          });
+          if (data && data.head.repo.full_name !== 'adobe/react-spectrum' && data.head.sha === forkHeadCommit) {
+            pr = pull_number;
+            break;
+          }
+        }
+      }
+    } catch (error) {
+      console.error(error);
+    }
+  } else {
+    pr = process.env.CIRCLE_PULL_REQUEST.split('/').pop();
   }
 
-  let pr = process.env.CIRCLE_PULL_REQUEST.split('/').pop();
-  await octokit.issues.createComment({
-    owner: 'adobe',
-    repo: 'react-spectrum',
-    issue_number: pr,
-    body: `Build successful! 🎉
+  if (pr != null) {
+    await octokit.issues.createComment({
+      owner: 'adobe',
+      repo: 'react-spectrum',
+      issue_number: pr,
+      body: `Build successful! 🎉
 
-* [View the storybook](https://reactspectrum.blob.core.windows.net/reactspectrum/${process.env.CIRCLE_SHA1}/storybook/index.html)
-* [View the storybook-16](https://reactspectrum.blob.core.windows.net/reactspectrum/${process.env.CIRCLE_SHA1}/storybook-16/index.html)
-* [View the documentation](https://reactspectrum.blob.core.windows.net/reactspectrum/${process.env.CIRCLE_SHA1}/docs/index.html)`
-  });
+  * [View the storybook](https://reactspectrum.blob.core.windows.net/reactspectrum/${process.env.CIRCLE_SHA1}/storybook/index.html)
+  * [View the storybook-16](https://reactspectrum.blob.core.windows.net/reactspectrum/${process.env.CIRCLE_SHA1}/storybook-16/index.html)
+  * [View the documentation](https://reactspectrum.blob.core.windows.net/reactspectrum/${process.env.CIRCLE_SHA1}/docs/index.html)`
+    });
+  }
 }

.github/actions/branch/action.yml

@@ -0,0 +1,5 @@
+name: 'Branch from fork'
+description: 'creates a branch based off PR from fork'
+runs:
+  using: 'node16'
+  main: 'index.js'

.github/actions/branch/index.js

@@ -0,0 +1,58 @@
+const core = require('@actions/core');
+const github = require('@actions/github');
+
+const octokit = new github.GitHub(process.env.GITHUB_TOKEN);
+run();
+// Creates a branch off a fork PR
+async function run() {
+  const context = github.context;
+  try {
+    // Get info of the fork PR
+    const prNumber = context.issue.number;
+    const {data} = await octokit.pulls.get({
+      ...context.repo,
+      pull_number: prNumber
+    });
+
+    // Only create/update a branch if the PR from a fork
+    if (data.head.repo.full_name !== context.payload.repository.full_name) {
+      const branch = `${data.user.login}-${data.head.ref}`;
+      const ref = `refs/heads/${branch}`;
+      const sha = data.merge_commit_sha;
+
+      let res;
+      // Look up if branch for fork PR exists in base repo
+      try {
+        res = await octokit.repos.getBranch({
+          ...context.repo,
+          branch
+        });
+      } catch (error) {
+        if (!(error.name === 'HttpError' && error.status === 404)) {
+          throw error;
+        } else {
+          // If branch doesn't exist for the forked PR, create one so we can get a
+          // build for it and return
+          await octokit.git.createRef({
+            ...context.repo,
+            ref,
+            sha
+          });
+          return;
+        }
+      }
+
+      // If branch already exists update it to match fork PR state.
+      if (res.status === 200) {
+        await octokit.git.updateRef({
+          ...context.repo,
+          sha,
+          ref: `heads/${branch}`,
+          force: true
+        })
+      }
+    }
+  } catch (error) {
+    core.setFailed(error.message);
+  }
+}

.github/workflows/pr-comment.yaml

@@ -0,0 +1,24 @@
+name: PR comment
+on: issue_comment
+
+jobs:
+  pr_commented:
+    name: PR comment workflow
+    if: |
+      github.event.issue.pull_request &&
+      github.repository == 'adobe/react-spectrum' &&
+      github.actor == 'LFDanLu'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@main
+      - name: Use Node 16
+        uses: actions/setup-node@v2
+        with:
+          node-version: '16'
+      - name: install
+        run: yarn install
+      - name: Comment contains trigger
+        if: contains(github.event.comment.body, 'GET_BUILD')
+        uses: ./.github/actions/branch
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}