[AI] Fix flaky Compare Sizes CI job

The job intermittently failed with "==> (not found) Artifact: build-stats"
due to a race condition: action-wait-for-check waited by commit SHA while
action-download-artifact searched by PR number, picking a newer still-running
workflow run whose artifacts hadn't been uploaded yet.

Fixes:
- Use commit SHA instead of PR number for PR artifact downloads to match
  the exact workflow run that was waited on
- Add if_no_artifact_found: warn to all download steps (defense in depth)
- Upgrade CLI download steps from v11 to v18 to support this parameter
- Add timeoutSeconds/intervalSeconds to all wait-for-check steps
- Expand failure detection to cover base branch builds and add warning
  step for incomplete builds
- Make bundle-stats-comment.mjs gracefully skip missing stats files
  instead of throwing
- Add if: !cancelled() to generate/post steps so they run after warnings

https://claude.ai/code/session_015TDkitgqM2TsgFSCuGaFuF

.github/workflows/size-compare.yml

@@ -50,6 +50,8 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
           checkName: web
           ref: ${{github.base_ref}}
+          timeoutSeconds: 1200
+          intervalSeconds: 30
       - name: Wait for ${{github.base_ref}} API build to succeed
         uses: fountainhead/action-wait-for-check@5a908a24814494009c4bb27c242ea38c93c593be # v1.2.0
         id: master-api-build
@@ -57,6 +59,8 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
           checkName: api
           ref: ${{github.base_ref}}
+          timeoutSeconds: 1200
+          intervalSeconds: 30
       - name: Wait for ${{github.base_ref}} CLI build to succeed
         uses: fountainhead/action-wait-for-check@5a908a24814494009c4bb27c242ea38c93c593be # v1.2.0
         id: master-cli-build
@@ -64,6 +68,8 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
           checkName: cli
           ref: ${{github.base_ref}}
+          timeoutSeconds: 1200
+          intervalSeconds: 30
 
       - name: Wait for PR build to succeed
         uses: fountainhead/action-wait-for-check@5a908a24814494009c4bb27c242ea38c93c593be # v1.2.0
@@ -72,6 +78,8 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
           checkName: web
           ref: ${{github.event.pull_request.head.sha}}
+          timeoutSeconds: 1200
+          intervalSeconds: 30
       - name: Wait for API PR build to succeed
         uses: fountainhead/action-wait-for-check@5a908a24814494009c4bb27c242ea38c93c593be # v1.2.0
         id: wait-for-api-build
@@ -79,6 +87,8 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
           checkName: api
           ref: ${{github.event.pull_request.head.sha}}
+          timeoutSeconds: 1200
+          intervalSeconds: 30
       - name: Wait for CLI PR build to succeed
         uses: fountainhead/action-wait-for-check@5a908a24814494009c4bb27c242ea38c93c593be # v1.2.0
         id: wait-for-cli-build
@@ -86,12 +96,32 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
           checkName: cli
           ref: ${{github.event.pull_request.head.sha}}
+          timeoutSeconds: 1200
+          intervalSeconds: 30
 
       - name: Report build failure
-        if: steps.wait-for-web-build.outputs.conclusion == 'failure' || steps.wait-for-api-build.outputs.conclusion == 'failure' || steps.wait-for-cli-build.outputs.conclusion == 'failure'
+        if: |
+          steps.wait-for-web-build.outputs.conclusion == 'failure' ||
+          steps.wait-for-api-build.outputs.conclusion == 'failure' ||
+          steps.wait-for-cli-build.outputs.conclusion == 'failure' ||
+          steps.master-web-build.outputs.conclusion == 'failure' ||
+          steps.master-api-build.outputs.conclusion == 'failure' ||
+          steps.master-cli-build.outputs.conclusion == 'failure'
         run: |
           echo "Build failed on PR branch or ${{github.base_ref}}"
           exit 1
+      - name: Warn on incomplete builds
+        if: |
+          steps.wait-for-web-build.outputs.conclusion != 'success' ||
+          steps.wait-for-api-build.outputs.conclusion != 'success' ||
+          steps.wait-for-cli-build.outputs.conclusion != 'success' ||
+          steps.master-web-build.outputs.conclusion != 'success' ||
+          steps.master-api-build.outputs.conclusion != 'success' ||
+          steps.master-cli-build.outputs.conclusion != 'success'
+        run: |
+          echo "::warning::Some builds did not complete successfully. Bundle stats may be incomplete."
+          echo "Base branch - web: ${{ steps.master-web-build.outputs.conclusion }}, api: ${{ steps.master-api-build.outputs.conclusion }}, cli: ${{ steps.master-cli-build.outputs.conclusion }}"
+          echo "PR - web: ${{ steps.wait-for-web-build.outputs.conclusion }}, api: ${{ steps.wait-for-api-build.outputs.conclusion }}, cli: ${{ steps.wait-for-cli-build.outputs.conclusion }}"
 
       - name: Download web build artifact from ${{github.base_ref}}
         uses: dawidd6/action-download-artifact@1f8785ff7a5130826f848e7f72725c85d241860f # v18
@@ -102,6 +132,7 @@ jobs:
           workflow_conclusion: '' # ignore the conclusion of the workflow, since we already checked it
           name: build-stats
           path: base
+          if_no_artifact_found: warn
       - name: Download API build artifact from ${{github.base_ref}}
         uses: dawidd6/action-download-artifact@1f8785ff7a5130826f848e7f72725c85d241860f # v18
         id: pr-api-build
@@ -111,41 +142,46 @@ jobs:
           workflow_conclusion: '' # ignore the conclusion of the workflow, since we already checked it
           name: api-build-stats
           path: base
+          if_no_artifact_found: warn
       - name: Download build stats from PR
         uses: dawidd6/action-download-artifact@1f8785ff7a5130826f848e7f72725c85d241860f # v18
         with:
-          pr: ${{github.event.pull_request.number}}
+          commit: ${{github.event.pull_request.head.sha}}
           workflow: build.yml
           workflow_conclusion: '' # ignore the conclusion of the workflow, since we already checked it
           name: build-stats
           path: head
           allow_forks: true
+          if_no_artifact_found: warn
       - name: Download API stats from PR
         uses: dawidd6/action-download-artifact@1f8785ff7a5130826f848e7f72725c85d241860f # v18
         with:
-          pr: ${{github.event.pull_request.number}}
+          commit: ${{github.event.pull_request.head.sha}}
           workflow: build.yml
           workflow_conclusion: '' # ignore the conclusion of the workflow, since we already checked it
           name: api-build-stats
           path: head
           allow_forks: true
+          if_no_artifact_found: warn
       - name: Download CLI build artifact from ${{github.base_ref}}
-        uses: dawidd6/action-download-artifact@ac66b43f0e6a346234dd65d4d0c8fbb31cb316e5 # v11
+        uses: dawidd6/action-download-artifact@1f8785ff7a5130826f848e7f72725c85d241860f # v18
         with:
           branch: ${{github.base_ref}}
           workflow: build.yml
           workflow_conclusion: '' # ignore the conclusion of the workflow, since we already checked it
           name: cli-build-stats
           path: base
+          if_no_artifact_found: warn
       - name: Download CLI stats from PR
-        uses: dawidd6/action-download-artifact@ac66b43f0e6a346234dd65d4d0c8fbb31cb316e5 # v11
+        uses: dawidd6/action-download-artifact@1f8785ff7a5130826f848e7f72725c85d241860f # v18
         with:
-          pr: ${{github.event.pull_request.number}}
+          commit: ${{github.event.pull_request.head.sha}}
           workflow: build.yml
           workflow_conclusion: '' # ignore the conclusion of the workflow, since we already checked it
           name: cli-build-stats
           path: head
           allow_forks: true
+          if_no_artifact_found: warn
       - name: Strip content hashes from stats files
         run: |
           if [ -f ./head/web-stats.json ]; then
@@ -162,6 +198,7 @@ jobs:
             fi
           done
       - name: Generate combined bundle stats comment
+        if: ${{ !cancelled() }}
         run: |
           node packages/ci-actions/bin/bundle-stats-comment.mjs \
             --base desktop-client=./base/web-stats.json \
@@ -175,6 +212,7 @@ jobs:
             --identifier combined \
             --format pr-body > bundle-stats-comment.md
       - name: Post combined bundle stats comment
+        if: ${{ !cancelled() }}
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           GITHUB_REPOSITORY: ${{ github.repository }}

packages/ci-actions/bin/bundle-stats-comment.mjs

@@ -5,7 +5,7 @@
  * Heavily inspired by https://github.com/twk3/rollup-size-compare-action (MIT).
  */
 
-import { readFile } from 'node:fs/promises';
+import { access, readFile } from 'node:fs/promises';
 import path from 'node:path';
 import process from 'node:process';
 
@@ -179,8 +179,19 @@ function parseArgs(argv) {
 }
 
 async function loadStats(filePath) {
+  const absolutePath = path.resolve(process.cwd(), filePath);
+
+  // Check if the file exists before trying to read it
+  try {
+    await access(absolutePath);
+  } catch {
+    console.error(
+      `[bundle-stats] Stats file not found: "${filePath}" — skipping`,
+    );
+    return null;
+  }
+
   try {
-    const absolutePath = path.resolve(process.cwd(), filePath);
     const fileContents = await readFile(absolutePath, 'utf8');
     const parsed = JSON.parse(fileContents);
 
@@ -196,7 +207,7 @@ async function loadStats(filePath) {
         ? error.message
         : 'Unknown error while parsing stats file';
     console.error(`[bundle-stats] Failed to parse "${filePath}": ${message}`);
-    throw new Error(`Failed to load stats file "${filePath}": ${message}`);
+    return null;
   }
 }
 
@@ -687,6 +698,13 @@ async function main() {
     );
     const headStats = await loadStats(section.headPath);
 
+    if (!baseStats || !headStats) {
+      console.error(
+        `[bundle-stats] Skipping section "${section.name}": missing ${!baseStats ? 'base' : 'head'} stats`,
+      );
+      continue;
+    }
+
     const statsDiff = getStatsDiff(baseStats, headStats);
     const chunkDiff = getChunkModuleDiff(baseStats, headStats);