workflows/labels: refactor to search instead of listing PRs

This doesn't provide much value in itself, yet, but is much more
flexible in the next step, when also looking at much older PRs.

.github/workflows/labels.yml

@@ -101,6 +101,9 @@ jobs:
             github.hook.wrap('request', async (request, options) => {
               // Requests to the /rate_limit endpoint do not count against the rate limit.
               if (options.url == '/rate_limit') return request(options)
+              // Search requests are in a different resource group, which allows 30 requests / minute.
+              // We do less than a handful each run, so not implementing throttling for now.
+              if (options.url.startsWith('/search/')) return request(options)
               stats.requests++
               if (['POST', 'PUT', 'PATCH', 'DELETE'].includes(options.method))
                 return writeLimits.schedule(request.bind(null, options))
@@ -131,17 +134,28 @@ jobs:
             if (process.env.UPDATED_WITHIN && !/^\d+$/.test(process.env.UPDATED_WITHIN))
               throw new Error('Please enter "updated within" as integer in hours.')
 
-            async function handle(pull_request, done, cutoff) {
+            async function handle(item) {
               try {
                 const log = (k,v,skip) => {
-                  core.info(`PR #${pull_request.number} - ${k}: ${v}` + (skip ? ' (skipped)' : ''))
+                  core.info(`#${item.number} - ${k}: ${v}` + (skip ? ' (skipped)' : ''))
                   return skip
                 }
 
-                if (log('Last updated at', pull_request.updated_at, new Date(pull_request.updated_at) < cutoff))
-                  return done()
+                log('Last updated at', item.updated_at)
                 stats.prs++
-                log('URL', pull_request.html_url)
+                log('URL', item.html_url)
+
+                const pull_number = item.number
+                const issue_number = item.number
+
+                // The search result is of a format that works for both issues and pull requests and thus
+                // does not have all fields of a full pull_request response. Notably, it is missing `head.sha`,
+                // which we need to fetch the workflow run below. When triggered via pull_request event,
+                // this field is already available.
+                const pull_request = item.head ? item : (await github.rest.pulls.get({
+                  ...context.repo,
+                  pull_number
+                })).data
 
                 const run_id = (await github.rest.actions.listWorkflowRuns({
                   ...context.repo,
@@ -188,7 +202,7 @@ jobs:
                     repositoryOwner: context.repo.owner,
                     token: core.getInput('github-token')
                   },
-                  path: path.resolve(pull_request.number.toString()),
+                  path: path.resolve(pull_number.toString()),
                   expectedHash: artifact.digest
                 })
 
@@ -197,7 +211,7 @@ jobs:
                 const before = Object.fromEntries(
                   (await github.paginate(github.rest.issues.listLabelsOnIssue, {
                     ...context.repo,
-                    issue_number: pull_request.number
+                    issue_number
                   }))
                   .map(({ name }) => [name, true])
                 )
@@ -205,17 +219,17 @@ jobs:
                 const approvals = new Set(
                   (await github.paginate(github.rest.pulls.listReviews, {
                     ...context.repo,
-                    pull_number: pull_request.number
+                    pull_number
                   }))
                   .filter(review => review.state == 'APPROVED')
                   .map(review => review.user?.id)
                 )
 
                 const maintainers = new Set(Object.keys(
-                  JSON.parse(await readFile(`${pull_request.number}/maintainers.json`, 'utf-8'))
+                  JSON.parse(await readFile(`${pull_number}/maintainers.json`, 'utf-8'))
                 ).map(m => Number.parseInt(m, 10)))
 
-                const evalLabels = JSON.parse(await readFile(`${pull_request.number}/changed-paths.json`, 'utf-8')).labels
+                const evalLabels = JSON.parse(await readFile(`${pull_number}/changed-paths.json`, 'utf-8')).labels
 
                 // Manage the labels
                 const after = Object.assign(
@@ -249,11 +263,11 @@ jobs:
 
                 await github.rest.issues.setLabels({
                   ...context.repo,
-                  issue_number: pull_request.number,
+                  issue_number,
                   labels
                 })
               } catch (cause) {
-                throw new Error(`Labeling PR #${pull_request.number} failed.`, { cause })
+                throw new Error(`Labeling #${item.number} failed.`, { cause })
               }
             }
 
@@ -280,18 +294,21 @@ jobs:
               })())
               core.info('cutoff timestamp: ' + cutoff.toISOString())
 
-              const prs = await github.paginate(
-                github.rest.pulls.list,
+              const items = await github.paginate(
+                github.rest.search.issuesAndPullRequests,
                 {
-                  ...context.repo,
-                  state: 'open',
-                  sort: 'updated',
-                  direction: 'desc',
-                },
-                (response, done) => response.data.map(pull_request => handle(pull_request, done, cutoff))
+                  q: [
+                    `repo:"${process.env.GITHUB_REPOSITORY}"`,
+                    'type:pr',
+                    'is:open',
+                    `updated:>=${cutoff.toISOString()}`
+                  ].join(' AND '),
+                  // TODO: Remove in 2025-10, when it becomes the default.
+                  advanced_search: true
+                }
               );
 
-              (await Promise.allSettled(prs.flat()))
+              (await Promise.allSettled(items.map(handle)))
                 .filter(({ status }) => status == 'rejected')
                 .map(({ reason }) => core.setFailed(`${reason.message}\n${reason.cause.stack}`))