From 1b774b373eb7fafebaa43adf9e086a690461201d Mon Sep 17 00:00:00 2001
From: David Lechner <david@pybricks.com>
Date: Wed, 30 Mar 2022 11:32:04 -0500
Subject: [PATCH] github/workflows: Comment on code size change instead of
 failing CI.

This changes the code size workflow to post a comment on pull requests with
the code size report.  It also removes the error threshold so that the test
won't fail if code size increases.

Allowable code size changes are subjective, so shouldn't cause CI to fail.
In addition, failing CI tests can cause other hooks like code coverage
reports to be suppressed, so this fixes that problem as well.

Fixes issue #8464.

Signed-off-by: David Lechner <david@pybricks.com>
---
 .github/workflows/code_size.yml         | 16 ++++++-
 .github/workflows/code_size_comment.yml | 64 +++++++++++++++++++++++++
 2 files changed, 79 insertions(+), 1 deletion(-)
 create mode 100644 .github/workflows/code_size_comment.yml

diff --git a/.github/workflows/code_size.yml b/.github/workflows/code_size.yml
index 3811d91349..d4f8b195ad 100644
--- a/.github/workflows/code_size.yml
+++ b/.github/workflows/code_size.yml
@@ -24,4 +24,18 @@ jobs:
     - name: Build
       run: source tools/ci.sh && ci_code_size_build
     - name: Compute code size difference
-      run: tools/metrics.py diff --error-threshold 0 ~/size0 ~/size1
+      run: tools/metrics.py diff ~/size0 ~/size1 | tee > diff
+    - name: Save PR number
+      if: github.event_name == 'pull_request'
+      env:
+        PR_NUMBER: ${{ github.event.number }}
+      run: echo $PR_NUMBER > pr_number
+    - name: Upload diff
+      if: github.event_name == 'pull_request'
+      uses: actions/upload-artifact@v3
+      with:
+        name: code-size-report
+        path: |
+          diff
+          pr_number
+        retention-days: 1
diff --git a/.github/workflows/code_size_comment.yml b/.github/workflows/code_size_comment.yml
new file mode 100644
index 0000000000..100e82f828
--- /dev/null
+++ b/.github/workflows/code_size_comment.yml
@@ -0,0 +1,64 @@
+name: Code size comment
+
+on:
+  workflow_run:
+    workflows: [Check code size]
+    types: [completed]
+
+jobs:
+  comment:
+    runs-on: ubuntu-20.04
+    steps:
+      - name: 'Download artifact'
+        id: download-artifact
+        uses: actions/github-script@v6
+        with:
+          script: |
+            const fs = require('fs');
+
+            const allArtifacts = await github.rest.actions.listWorkflowRunArtifacts({
+               owner: context.repo.owner,
+               repo: context.repo.repo,
+               run_id: context.payload.workflow_run.id,
+            });
+
+            const matchArtifact = allArtifacts.data.artifacts.filter((artifact) => {
+              return artifact.name == "code-size-report"
+            });
+
+            if (matchArtifact.length === 0) {
+              return false;
+            }
+
+            const download = await github.rest.actions.downloadArtifact({
+               owner: context.repo.owner,
+               repo: context.repo.repo,
+               artifact_id: matchArtifact[0].id,
+               archive_format: 'zip',
+            });
+
+            fs.writeFileSync(`${process.env.GITHUB_WORKSPACE}/code-size-report.zip`, Buffer.from(download.data));
+
+            return true;
+      - name: 'Unzip artifact'
+        if: steps.download-artifact.outputs.result
+        run: unzip code-size-report.zip
+      - name: Post comment to pull request
+        if: steps.download-artifact.outputs.result
+        uses: actions/github-script@v6
+        with:
+          github-token: ${{secrets.GITHUB_TOKEN}}
+          script: |
+            const fs = require('fs');
+
+            github.rest.issues.createComment({
+              issue_number: Number(fs.readFileSync('pr_number')),
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: `Code size report:
+
+            \`\`\`
+            ${fs.readFileSync('diff')}
+            \`\`\`
+            `,
+            });