From f283b50e86ad8c202c6f31f0cae6e62959aa1d6d Mon Sep 17 00:00:00 2001
From: Florian Haas <florian@cleura.com>
Date: Wed, 16 Aug 2023 12:27:24 +0200
Subject: [PATCH] build: Post pull request comments on build check failure

Without this change, when a PR results in a build failure, the onus is
on the PR submitter to find the failed build, and the corresponding
build log. That is somewhat tedious and not particularly intuituive.

Instead, use a separate GitHub Action that posts a comment back to the
PR thread, containing a direct link to the failed build log. This
should hopefully make it easier for PR submitters to find out what
exactly their submitted change breaks.

References:
https://github.com/quipper/comment-failure-action/
https://github.com/quipper/comment-failure-action/pull/6
---
 .github/workflows/build.yml   |  2 +-
 .github/workflows/check.yml   |  2 +-
 .github/workflows/comment.yml | 20 ++++++++++++++++++++
 .github/workflows/deploy.yml  |  2 +-
 4 files changed, 23 insertions(+), 3 deletions(-)
 create mode 100644 .github/workflows/comment.yml

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index d731f0ee6..33f66b1eb 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -36,7 +36,7 @@ jobs:
           - '3.9'
           - '3.10'
 
-name: Build
+name: build
 
 # We want to run this workflow on each push to a topic branch, and on
 # each pull request. Once we merge to main, we want to run the
diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index cb0e8b891..46c8d0cf5 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -16,7 +16,7 @@ jobs:
         run: |
           tox -e check-prod
 
-name: 'Check links'
+name: check
 
 # We want to run this workflow every time we build the site.
 # In addition, we want to run it once a week on a schedule.
diff --git a/.github/workflows/comment.yml b/.github/workflows/comment.yml
new file mode 100644
index 000000000..189da07e5
--- /dev/null
+++ b/.github/workflows/comment.yml
@@ -0,0 +1,20 @@
+# Post a comment back on a PR thread, in case an associated workflow
+# failed. Note that comment-failure-action is a no-op in case the
+# workflow was not invoked in response to a PR. In other words, this
+# action only creates comments for workflows configured with
+# "on: pull_request".
+---
+jobs:
+  comment-failure:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: quipper/comment-failure-action@v0.1.1
+
+name: comment
+
+'on':
+  workflow_run:
+    types:
+      - completed
+    workflows:
+      - build
diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 37e759689..adc2d56ac 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -17,7 +17,7 @@ jobs:
       - name: Deploy to gh-pages
         run: tox -e deploy-github
 
-name: Deploy
+name: deploy
 
 'on':
   push: