From 0bd051cc1638baeacdf6cce375314f6ecf592f38 Mon Sep 17 00:00:00 2001
From: Em Sharnoff <sharnoff@neon.tech>
Date: Tue, 24 Sep 2024 19:07:55 -0700
Subject: [PATCH 1/3] CI: Add PR title checker

Loosely adapted the workflow from what we have in neondatabase/cloud,
but with the format changed to match what we've previously done in this
repo.
---
 .github/workflows/pr-format-verification.yml | 66 ++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 .github/workflows/pr-format-verification.yml

diff --git a/.github/workflows/pr-format-verification.yml b/.github/workflows/pr-format-verification.yml
new file mode 100644
index 000000000..a222b1224
--- /dev/null
+++ b/.github/workflows/pr-format-verification.yml
@@ -0,0 +1,66 @@
+name: PR format verification
+
+on:
+  pull_request:
+    branches:
+      - main
+    types:
+      # By default, a workflow only runs when a pull_request event's activity type is opened, synchronize, or reopened.
+      - opened
+      - synchronize
+      - edited
+      - reopened
+
+defaults:
+  run:
+    shell: bash -euo pipefail {0}
+
+jobs:
+  pr-format-verification:
+    name: Check PR title
+    # Only run the job if the PR is not created by dependabot.
+    # We still want dependabot PRs to go through, they contain important security updates,
+    # and there's no good way of getting dependabot to conform to our PR format
+    if: github.actor != 'dependabot[bot]'
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Verify PR Title
+        env:
+          ON_FAILURE: |
+            PR title must be prefixed with component names (e.g., "vm-builder: ..." or "agent/subsystem,neonvm: ...") OR body must contain the string "<!-- affects all -->"
+
+            Some common component names:
+             * "agent" (the autoscaler-agent)
+             * "plugin" (the scheduler)
+             * "neonvm-controller" / "neonvm-runner" / "vm-builder" (individual parts of "neonvm")
+             * "neonvm" (when the PR affects most neonvm-related components)
+             * "ci" / "CI" - depending on your capitalization
+
+            Some common subsystems:
+             * "agent/billing" (generation of billing events in the autoscaler-agent)
+             * "agent/core" (core scaling algorithm in the autoscaler-agent)
+             * "plugin/trans" (core resource logic in the scheduler plugin)
+             * "ci/lint" (lints workflow in CI)
+
+            Check recent PRs for examples: https://github.com/neondatabase/autoscaling/pulls?q=is%3Apr+is%3Aclosed
+        run: |
+          title="$(jq --raw-output .pull_request.title "$GITHUB_EVENT_PATH")"
+          body="$(jq --raw-output .pull_request.body "$GITHUB_EVENT_PATH")"
+
+          # If the PR body contains the magic string, ignore it.
+          if grep -q '<!-- affects all -->' <(echo "$body") >/dev/null ; then
+              exit 0
+          fi
+
+          # If the title looks like 'Revert "..."', then give it a pass.
+          if grep -q '^Revert "' <(echo "$title") >/dev/null ; then
+              exit 0
+          fi
+
+          # Check that title matches the regex:
+          TITLE_REGEX='^[a-z0-9-.]+(/[a-z0-9-.]+)*(,[a-z0-9-.]+(/[a-z0-9-.]+)*)*: .*$'
+
+          if ! grep -qP "$TITLE_REGEX" <(echo "$title") >/dev/null ; then
+              echo "$ON_FAILURE" >/dev/stderr
+              exit 1
+          fi

From 37089eb9fd1fc51a189310287cec25e019847527 Mon Sep 17 00:00:00 2001
From: Em Sharnoff <sharnoff@neon.tech>
Date: Tue, 24 Sep 2024 20:22:07 -0700
Subject: [PATCH 2/3] add -i flag to grep

Meant to include this; forgot!
---
 .github/workflows/pr-format-verification.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/pr-format-verification.yml b/.github/workflows/pr-format-verification.yml
index a222b1224..26e94af38 100644
--- a/.github/workflows/pr-format-verification.yml
+++ b/.github/workflows/pr-format-verification.yml
@@ -60,7 +60,7 @@ jobs:
           # Check that title matches the regex:
           TITLE_REGEX='^[a-z0-9-.]+(/[a-z0-9-.]+)*(,[a-z0-9-.]+(/[a-z0-9-.]+)*)*: .*$'
 
-          if ! grep -qP "$TITLE_REGEX" <(echo "$title") >/dev/null ; then
+          if ! grep -qiP "$TITLE_REGEX" <(echo "$title") >/dev/null ; then
               echo "$ON_FAILURE" >/dev/stderr
               exit 1
           fi

From 123ed021d0634529216cb34f8ba4e2b5c1bc9cb9 Mon Sep 17 00:00:00 2001
From: Em Sharnoff <sharnoff@neon.tech>
Date: Mon, 30 Sep 2024 15:03:36 -0700
Subject: [PATCH 3/3] break up title regex

---
 .github/workflows/pr-format-verification.yml | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/pr-format-verification.yml b/.github/workflows/pr-format-verification.yml
index 26e94af38..1a49a390f 100644
--- a/.github/workflows/pr-format-verification.yml
+++ b/.github/workflows/pr-format-verification.yml
@@ -58,7 +58,11 @@ jobs:
           fi
 
           # Check that title matches the regex:
-          TITLE_REGEX='^[a-z0-9-.]+(/[a-z0-9-.]+)*(,[a-z0-9-.]+(/[a-z0-9-.]+)*)*: .*$'
+          WORD='[a-z0-9-.]+'
+          COMPONENT="$WORD(/$WORD)*" # one or more '/'-separated words
+          TITLE_PREFIX="$COMPONENT(,$COMPONENT)*" # one or more ','-separated components
+          TITLE_MSG='.+' # Any non-empty message.
+          TITLE_REGEX="^$TITLE_PREFIX: $TITLE_MSG\$"
 
           if ! grep -qiP "$TITLE_REGEX" <(echo "$title") >/dev/null ; then
               echo "$ON_FAILURE" >/dev/stderr