workflow/labels: switch to a scheduled trigger (#416808)

Author: philiptaron

.github/workflows/labels.yml

@@ -6,16 +6,23 @@
 name: "Label PR"
 
 on:
+  schedule:
+    - cron: '37 * * * *'
   workflow_call:
-  workflow_run:
-    workflows:
-      - Review dismissed
-      - Review submitted
-    types: [completed]
+  workflow_dispatch:
+    inputs:
+      updatedWithin:
+        description: 'Updated within [hours]'
+        type: number
+        required: false
+        default: 0 # everything since last run
 
 concurrency:
-  group: labels-${{ github.workflow }}-${{ github.event_name }}-${{ github.event.pull_request.number || github.run_id }}
-  cancel-in-progress: true
+  # This explicitly avoids using `run_id` for the concurrency key to make sure that only
+  # *one* non-PR run can run at a time.
+  group: labels-${{ github.workflow }}-${{ github.event_name }}-${{ github.event.pull_request.number }}
+  # PR- and manually-triggered runs will be cancelled, but scheduled runs will be queued.
+  cancel-in-progress: ${{ github.event_name != 'schedule' }}
 
 permissions:
   issues: write # needed to create *new* labels
@@ -31,64 +38,111 @@ jobs:
     runs-on: ubuntu-24.04-arm
     if: "!contains(github.event.pull_request.title, '[skip treewide]')"
     steps:
-      - uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
-        id: eval
-        with:
-          script: |
-            const run_id = (await github.rest.actions.listWorkflowRuns({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              workflow_id: 'eval.yml',
-              event: 'pull_request_target',
-              head_sha: context.payload.pull_request?.head.sha ?? context.payload.workflow_run.head_sha
-            })).data.workflow_runs[0]?.id
-            core.setOutput('run-id', run_id)
-
-      - name: Download the comparison results
-        if: steps.eval.outputs.run-id
-        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
-        with:
-          run-id: ${{ steps.eval.outputs.run-id }}
-          github-token: ${{ github.token }}
-          pattern: comparison
-          path: comparison
-          merge-multiple: true
-
-      - name: Labels from eval
-        if: steps.eval.outputs.run-id && github.event_name != 'pull_request'
+      - name: Install dependencies
+        run: npm install @actions/artifact
+
+      - name: Labels from API data and Eval results
         uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        env:
+          UPDATED_WITHIN: ${{ inputs.updatedWithin }}
         with:
           script: |
+            const path = require('node:path')
+            const { DefaultArtifactClient } = require('@actions/artifact')
             const { readFile } = require('node:fs/promises')
 
-            let pull_requests
-            if (context.payload.workflow_run) {
-              // PRs from forks don't have any PRs associated by default.
-              // Thus, we request the PR number with an API call *to* the fork's repo.
-              // Multiple pull requests can be open from the same head commit, either via
-              // different base branches or head branches.
-              const { head_repository, head_sha, repository } = context.payload.workflow_run
-              pull_requests = (await github.paginate(github.rest.repos.listPullRequestsAssociatedWithCommit, {
-                owner: head_repository.owner.login,
-                repo: head_repository.name,
-                commit_sha: head_sha
-              })).filter(pull_request => pull_request.base.repo.id == repository.id)
-            } else {
-              pull_requests = [ context.payload.pull_request ]
+            const artifactClient = new DefaultArtifactClient()
+
+            if (process.env.UPDATED_WITHIN && !/^\d+$/.test(process.env.UPDATED_WITHIN))
+              throw new Error('Please enter "updated within" as integer in hours.')
+
+            const cutoff = new Date(await (async () => {
+              // Always run for Pull Request triggers, no cutoff since there will be a single
+              // response only anyway. 0 is the Unix epoch, so always smaller.
+              if (context.payload.pull_request?.number) return 0
+
+              // Manually triggered via UI when updatedWithin is set. Will fallthrough to the last
+              // option if the updatedWithin parameter is set to 0, which is the default.
+              const updatedWithin = Number.parseInt(process.env.UPDATED_WITHIN, 10)
+              if (updatedWithin) return new Date().getTime() - updatedWithin * 60 * 60 * 1000
+
+              // Normally a scheduled run, but could be workflow_dispatch, see above. Go back as far
+              // as the last successful run of this workflow to make sure we are not leaving anyone
+              // behind on GHA failures.
+              return (await github.rest.actions.listWorkflowRuns({
+                ...context.repo,
+                workflow_id: 'labels.yml',
+                event: 'schedule',
+                status: 'success',
+                exclude_pull_requests: true
+              })).data.workflow_runs[0]?.created_at
+            })())
+            core.info('cutoff timestamp: ' + cutoff.toISOString())
+
+            // To simplify this action's logic we fetch the pull_request data again below, even if
+            // we are already in a pull_request event's context and would have the data readily
+            // available. We do this by filtering the list of pull requests with head and base
+            // branch - there can only be a single open Pull Request for any such combination.
+            const prEventCondition = !context.payload.pull_request ? undefined : {
+              // "label" is in the format of `user:branch` or `org:branch`
+              head: context.payload.pull_request.head.label,
+              base: context.payload.pull_request.base.ref
             }
 
-            await Promise.all(
-              pull_requests.map(async (pull_request) => {
-                const pr = {
-                  owner: context.repo.owner,
-                  repo: context.repo.repo,
-                  issue_number: pull_request.number
-                }
+            await github.paginate(
+              github.rest.pulls.list,
+              {
+                ...context.repo,
+                state: 'open',
+                sort: 'updated',
+                direction: 'desc',
+                ...prEventCondition
+              },
+              async (response, done) => await Promise.all(response.data.map(async (pull_request) => {
+                const log = (k,v) => core.info(`PR #${pull_request.number} - ${k}: ${v}`)
+
+                log('Last updated at', pull_request.updated_at)
+                if (new Date(pull_request.updated_at) < cutoff) return done()
+
+                const run_id = (await github.rest.actions.listWorkflowRuns({
+                  ...context.repo,
+                  workflow_id: 'eval.yml',
+                  event: 'pull_request_target',
+                  // For PR events, the workflow run is still in progress with this job itself.
+                  status: prEventCondition ? 'in_progress' : 'success',
+                  exclude_pull_requests: true,
+                  head_sha: pull_request.head.sha
+                })).data.workflow_runs[0]?.id
+
+                // Newer PRs might not have run Eval to completion, yet. We can skip them, because this
+                // job will be run as part of that Eval run anyway.
+                log('Last eval run', run_id)
+                if (!run_id) return;
+
+                const artifact = (await github.rest.actions.listWorkflowRunArtifacts({
+                  ...context.repo,
+                  run_id,
+                  name: 'comparison'
+                })).data.artifacts[0]
+
+                // Instead of checking the boolean artifact.expired, we will give us a minute to
+                // actually download the artifact in the next step and avoid that race condition.
+                log('Artifact expires at', artifact.expires_at)
+                if (new Date(artifact.expires_at) < new Date(new Date().getTime() + 60 * 1000)) return;
+
+                await artifactClient.downloadArtifact(artifact.id, {
+                  findBy: {
+                    repositoryName: context.repo.repo,
+                    repositoryOwner: context.repo.owner,
+                    token: core.getInput('github-token')
+                  },
+                  path: path.resolve('comparison'),
+                  expectedHash: artifact.digest
+                })
 
                 // Get all currently set labels that we manage
                 const before =
-                  (await github.paginate(github.rest.issues.listLabelsOnIssue, pr))
-                  .map(({ name }) => name)
+                  pull_request.labels.map(({ name }) => name)
                   .filter(name =>
                     name.startsWith('10.rebuild') ||
                     name == '11.by: package-maintainer' ||
@@ -98,8 +152,7 @@ jobs:
 
                 const approvals = new Set(
                   (await github.paginate(github.rest.pulls.listReviews, {
-                    owner: context.repo.owner,
-                    repo: context.repo.repo,
+                    ...context.repo,
                     pull_number: pull_request.number
                   }))
                   .filter(review => review.state == 'APPROVED')
@@ -119,7 +172,8 @@ jobs:
                 await Promise.all(
                   before.filter(name => !after.includes(name))
                   .map(name => github.rest.issues.removeLabel({
-                    ...pr,
+                    ...context.repo,
+                    issue_number: pull_request.number
                     name
                   }))
                 )
@@ -128,17 +182,18 @@ jobs:
                 const added = after.filter(name => !before.includes(name))
                 if (added.length > 0) {
                   await github.rest.issues.addLabels({
-                    ...pr,
+                    ...context.repo,
+                    issue_number: pull_request.number
                     labels: added
                   })
                 }
-              })
+              }))
             )
 
       - uses: actions/labeler@8558fd74291d67161a8a78ce36a881fa63b766a9 # v5.0.0
         name: Labels from touched files
         if: |
-          github.event_name != 'workflow_run' &&
+          github.event_name == 'pull_request_target' &&
           github.event.pull_request.head.repo.owner.login != 'NixOS' || !(
             github.head_ref == 'haskell-updates' ||
             github.head_ref == 'python-updates' ||
@@ -153,7 +208,7 @@ jobs:
       - uses: actions/labeler@8558fd74291d67161a8a78ce36a881fa63b766a9 # v5.0.0
         name: Labels from touched files (no sync)
         if: |
-          github.event_name != 'workflow_run' &&
+          github.event_name == 'pull_request_target' &&
           github.event.pull_request.head.repo.owner.login != 'NixOS' || !(
             github.head_ref == 'haskell-updates' ||
             github.head_ref == 'python-updates' ||
@@ -171,7 +226,7 @@ jobs:
         # This is to avoid the mass of labels there, which is mostly useless - and really annoying for
         # the backport labels.
         if: |
-          github.event_name != 'workflow_run' &&
+          github.event_name == 'pull_request_target' &&
           github.event.pull_request.head.repo.owner.login == 'NixOS' && (
             github.head_ref == 'haskell-updates' ||
             github.head_ref == 'python-updates' ||