From 8499bbdd17d9ab6b5921425ffae2ba2ea0b709dc Mon Sep 17 00:00:00 2001
From: Joey Perrott <josephperrott.github@gmail.com>
Date: Wed, 29 Jan 2020 09:47:54 -0800
Subject: [PATCH] ci: only lint commit messages in the PR (#35035)

PR Close #35035
---
 tools/gulp-tasks/validate-commit-message.js | 31 +++++++--------------
 tools/rebase-pr.js                          |  1 -
 tools/utils/get-refs-and-shas-for-target.js | 18 +++++++-----
 3 files changed, 21 insertions(+), 29 deletions(-)

diff --git a/tools/gulp-tasks/validate-commit-message.js b/tools/gulp-tasks/validate-commit-message.js
index 0930c6f64f..7fbf56f7f5 100644
--- a/tools/gulp-tasks/validate-commit-message.js
+++ b/tools/gulp-tasks/validate-commit-message.js
@@ -8,38 +8,27 @@
 
 
 // tslint:disable:no-console
-module.exports = (gulp) => () => {
+module.exports = (gulp) => async() => {
   try {
-    if (process.env['CIRCLECI'] === 'true' && !process.env['CIRCLE_PR_NUMBER']) {
+    if (process.env['CI'] === 'true' && process.env['CI_PULL_REQUEST'] === 'false') {
       console.info(
-        `Since commit messages are validated as part of the PR review process,\n` +
-        `we do not need to commit messages on CI runs on upstream branches.\n\n` +
-        `Skipping validate-commit-message check`
-        )
+          `Since valid commit messages are enforced by PR linting on CI,\n` +
+          `we do not need to validate commit messages on CI runs on upstream branches.\n\n` +
+          `Skipping validate-commit-message check`);
       process.exit();
     }
     const validateCommitMessage = require('../validate-commit-message');
     const shelljs = require('shelljs');
+    const getRefsAndShasForTarget = require('../utils/get-refs-and-shas-for-target');
 
     shelljs.set('-e');  // Break on error.
 
-    let baseBranch = 'master';
-    const currentVersion = require('semver').parse(require('../../package.json').version);
-    const baseHead =
-        shelljs
-            .exec(`git ls-remote --heads origin ${currentVersion.major}.${currentVersion.minor}.*`)
-            .trim()
-            .split('\n')
-            .pop();
-    if (baseHead) {
-      const match = /refs\/heads\/(.+)/.exec(baseHead);
-      baseBranch = match && match[1] || baseBranch;
-    }
+    const target = await getRefsAndShasForTarget(process.env['CIRCLE_PR_NUMBER']);
 
     // We need to fetch origin explicitly because it might be stale.
     // I couldn't find a reliable way to do this without fetch.
     const result = shelljs.exec(
-        `git fetch origin ${baseBranch} && git log --reverse --format=%s origin/${baseBranch}..HEAD | grep -v "#34769"`);
+        `git log --reverse --format=%s ${target.commonAncestorSha}..${target.latestShaOfPrBranch}`);
 
     if (result.code) {
       throw new Error(`Failed to fetch commits: ${result.stderr}`);
@@ -47,10 +36,10 @@ module.exports = (gulp) => () => {
 
     const commitsByLine = result.trim().split(/\n/).filter(line => line != '');
 
-    console.log(`Examining ${commitsByLine.length} commit(s) between ${baseBranch} and HEAD`);
+    console.log(`Examining ${commitsByLine.length} commit(s) between ${target.base.ref} and HEAD`);
 
     if (commitsByLine.length == 0) {
-      console.log(`There are zero new commits between ${baseBranch} and HEAD`);
+      console.log(`There are zero new commits between ${target.base.ref} and HEAD`);
     }
 
     const disallowSquashCommits = true;
diff --git a/tools/rebase-pr.js b/tools/rebase-pr.js
index 53f13aa3d0..53d4280c71 100644
--- a/tools/rebase-pr.js
+++ b/tools/rebase-pr.js
@@ -107,4 +107,3 @@ async function _main(repository, prNumber) {
   await exec(`git rebase origin/${target.base.ref}`);
   console.log('Rebase successful.');
 }
-
diff --git a/tools/utils/get-refs-and-shas-for-target.js b/tools/utils/get-refs-and-shas-for-target.js
index e0f18b4fd3..42a8989069 100644
--- a/tools/utils/get-refs-and-shas-for-target.js
+++ b/tools/utils/get-refs-and-shas-for-target.js
@@ -6,6 +6,9 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+// This script uses `console` to print messages to the user.
+// tslint:disable:no-console
+
 const https = require('https');
 const util = require('util');
 const child_process = require('child_process');
@@ -68,18 +71,19 @@ module.exports = async function getRefsAndShasForTarget(prNumber) {
   const {stdout: commonAncestorSha} =
       await exec(`git merge-base origin/${result.base.ref} ${latestShaOfPrBranch}`);
 
-  return {
+  const output = {
     base: {
-      ref: result.base.ref.trim(),
-      sha: result.base.sha.trim(),
+      ref: result.base.ref,
+      sha: result.base.sha,
     },
     head: {
-      ref: result.head.ref.trim(),
-      sha: result.head.sha.trim()
+      ref: result.head.ref,
+      sha: result.head.sha,
     },
     commonAncestorSha: commonAncestorSha.trim(),
     latestShaOfTargetBranch: latestShaOfTargetBranch.trim(),
     latestShaOfPrBranch: latestShaOfPrBranch.trim(),
-  }
+  };
 
-}
+  return output;
+};