ci(pr-title): reduce API calls and check out current revision

.github/workflows/pr-title.yml

@@ -25,7 +25,7 @@ jobs:
       - name: Checkout base revision
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
-          ref: ${{ github.event.pull_request.base.sha }}
+          ref: ${{ github.sha }}
           persist-credentials: false
 
       - name: Auto-rename GitHub revert title to Conventional Commit
@@ -63,6 +63,8 @@ jobs:
             core.info(`PR title OK: ${title}`)
 
             const type = match[3]
+            if (!/^(?:feat|fix|perf|docs)$/.test(type)) return
+
             const changedFiles = await github.paginate(github.rest.pulls.listFiles, {
               ...context.repo,
               pull_number: pullRequest.number,
@@ -71,13 +73,17 @@ jobs:
             const files = []
             const { appendChangedPaths, isInternalOnly } = require('./scripts/release/changelog')
             appendChangedPaths(files, changedFiles)
-            if (/^(?:feat|fix|perf|docs)$/.test(type) && isInternalOnly(files)) {
+            if (isInternalOnly(files)) {
               core.setFailed(`PR title type "${type}" is public, but every changed file is internal. ` +
                 'Use test, bench, ci, or chore.')
             }
 
       - name: Sync labels with PR title
-        if: steps.rename.outputs.renamed != 'true'
+        if: >-
+          steps.rename.outputs.renamed != 'true' &&
+          (github.event.action == 'opened' ||
+          github.event.action == 'reopened' ||
+          (github.event.action == 'edited' && github.event.changes.title != null))
         uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           script: |

scripts/pr-title.spec.mjs

@@ -0,0 +1,81 @@
+import assert from 'node:assert/strict'
+import fs from 'node:fs'
+import vm from 'node:vm'
+
+import { describe, it } from 'mocha'
+import YAML from 'yaml'
+
+const workflow = YAML.parse(fs.readFileSync(new URL('../.github/workflows/pr-title.yml', import.meta.url), 'utf8'))
+const job = workflow.jobs['conventional-commit']
+const steps = new Map()
+for (const step of job.steps) steps.set(step.name, step)
+
+const checkout = steps.get('Checkout base revision')
+const validation = steps.get('Validate PR title and release-note context')
+const labelSync = steps.get('Sync labels with PR title')
+const validateTitle = vm.runInNewContext(
+  `(async function validateTitle (context, core, github, process, require) {\n${validation.with.script}\n})`
+)
+const releaseHelpers = {
+  appendChangedPaths: Function.prototype,
+  isInternalOnly: () => false,
+}
+const loadReleaseHelpers = () => releaseHelpers
+
+describe('PR title workflow', () => {
+  it('lists changed files only for public title types', async () => {
+    const expectedCallsByType = new Map([
+      ['feat', 1],
+      ['fix', 1],
+      ['perf', 1],
+      ['docs', 1],
+      ['style', 0],
+      ['refactor', 0],
+      ['test', 0],
+      ['bench', 0],
+      ['build', 0],
+      ['ci', 0],
+      ['chore', 0],
+      ['revert', 0],
+    ])
+    const validations = []
+
+    for (const [type, expectedCalls] of expectedCallsByType) {
+      let listFilesCalls = 0
+      const context = {
+        repo: { owner: 'DataDog', repo: 'dd-trace-js' },
+        payload: { pull_request: { number: 1, title: `${type}: change` } },
+      }
+      const core = {
+        info: Function.prototype,
+        setFailed: assert.fail,
+      }
+      const github = {
+        paginate: () => {
+          listFilesCalls++
+          return []
+        },
+        rest: { pulls: { listFiles: Function.prototype } },
+      }
+      const process = { env: { PR_TITLE_PATTERN: job.env.PR_TITLE_PATTERN } }
+
+      validations.push(validateTitle(context, core, github, process, loadReleaseHelpers))
+
+      assert.strictEqual(listFilesCalls, expectedCalls, type)
+    }
+
+    await Promise.all(validations)
+  })
+
+  it('syncs labels only for events that can require reconciliation', () => {
+    assert.strictEqual(labelSync.if.replaceAll(/\s+/g, ' '),
+      "steps.rename.outputs.renamed != 'true' && " +
+      "(github.event.action == 'opened' || " +
+      "github.event.action == 'reopened' || " +
+      "(github.event.action == 'edited' && github.event.changes.title != null))")
+  })
+
+  it('checks out the workflow revision', () => {
+    assert.strictEqual(checkout.with.ref, '$' + '{{ github.sha }}')
+  })
+})