Make "Munge PR" more intelligent

.github/workflows/generate.sh

@@ -1,11 +1,16 @@
 #!/usr/bin/env bash
 set -Eeuo pipefail
+
+#
+# NOTE: this is *not* a good example for integrating these tests into your own repository!
+# If you want that, check out https://github.com/docker-library/golang/blob/3f2c52653043f067156ce4f41182c2a758c4c857/.github/workflows/ci.yml instead.
+#
   
 bashbrewDir="$1"; shift
 
 if [ "$#" -eq 0 ]; then
 	git fetch --quiet https://github.com/docker-library/official-images.git master
-	changes="$(git diff --numstat FETCH_HEAD...HEAD -- library/ | cut -d$'\t' -f3-)"
+	changes="$(git diff --no-renames --name-only --diff-filter='d' FETCH_HEAD...HEAD -- library/)"
 	repos="$(xargs -rn1 basename <<<"$changes")"
 	set -- $repos
 fi

.github/workflows/munge-pr.yml

@@ -13,8 +13,8 @@ env:
 
 jobs:
 
-  apply-labels:
-    name: Apply Labels
+  gather:
+    name: Gather Metadata
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -22,34 +22,63 @@ jobs:
           # ideally this would be "github.event.pull_request.merge_commit_sha" but according to https://docs.github.com/en/free-pro-team@latest/rest/reference/pulls#get-a-pull-request if "mergeable" is null (meaning there's a background job in-progress to check mergeability), that value is undefined...
           ref: ${{ github.event.pull_request.head.sha }}
           fetch-depth: 0
-      - id: labels
-        name: Gather List
+      - id: gather
+        name: Affected Images
         run: |
           git fetch --quiet https://github.com/docker-library/official-images.git master
-          labels="$(git diff --numstat FETCH_HEAD...HEAD -- library/ | cut -d$'\t' -f3-)"
-          if [ -n "$labels" ] && newImages="$(git diff --name-only --diff-filter=A FETCH_HEAD...HEAD -- $labels)" && [ -n "$newImages" ]; then
-            labels+=$'\nnew-image'
+          images="$(git diff --no-renames --name-only FETCH_HEAD...HEAD -- library/)"
+          if [ -n "$images" ]; then
+            new="$(git diff --no-renames --name-only --diff-filter=A FETCH_HEAD...HEAD -- $images)"
+            deleted="$(git diff --no-renames --name-only --diff-filter=D FETCH_HEAD...HEAD -- $images)"
+          else
+            new=
+            deleted=
           fi
-          labels="$(jq -Rsc 'rtrimstr("\n") | split("\n") | { labels: ., count: length }' <<<"$labels")"
-          jq . <<<"$labels"
-          echo "::set-output name=labels::$labels"
+          export images new deleted
+          images="$(jq -cn '
+            (env.images | rtrimstr("\n") | split("\n")) as $images
+            | (env.new | rtrimstr("\n") | split("\n")) as $new
+            | (env.deleted | rtrimstr("\n") | split("\n")) as $deleted
+            | {
+              images: $images,
+              count: ($images | length),
+              new: $new,
+              deleted: $deleted,
+            }
+          ')"
+          jq . <<<"$images"
+          echo "::set-output name=images::$images"
+    outputs:
+      images: '${{ steps.gather.outputs.images }}'
+
+  apply-labels:
+    name: Apply Labels
+    runs-on: ubuntu-latest
+    needs: gather
+    if: fromJSON(needs.gather.outputs.images).count > 0
+    steps:
       - name: Apply Labels
         uses: actions/github-script@v3
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
-            const data = ${{ steps.labels.outputs.labels }};
+            const data = ${{ needs.gather.outputs.images }};
+            var labels = data.images;
+            if (data.new.length > 0) {
+              labels.push('new-image');
+            }
             github.issues.addLabels({
               owner: context.repo.owner,
               repo: context.repo.repo,
               issue_number: context.payload.pull_request.number,
-              labels: data.labels,
+              labels: labels,
             });
-        if: fromJSON(steps.labels.outputs.labels).count > 0
 
   diff:
     name: Diff Comment
     runs-on: ubuntu-latest
+    needs: gather
+    if: fromJSON(needs.gather.outputs.images).count > 0
     steps:
       - uses: actions/checkout@v2
         with:
@@ -62,15 +91,23 @@ jobs:
           bashbrewVersion="$(< bashbrew-version)"
           docker build --pull --tag oisupport/bashbrew:base "https://github.com/docker-library/bashbrew.git#v$bashbrewVersion"
           docker build --tag oisupport/bashbrew:diff-pr .
-      - id: diff
-        name: Generate Diff
+      - name: Gather Maintainers
+        env:
+          IMAGES: ${{ needs.gather.outputs.images }}
+        run: |
+          files="$(jq <<<"$IMAGES" -r '.images | map(@sh) | join(" ")')"
+          eval "set -- $files"
+          for f; do
+            if [ -s "$f" ]; then
+              docker run --rm --read-only --tmpfs /tmp oisupport/bashbrew:diff-pr \
+                bashbrew cat --format '  - `{{ $.RepoName }}`:{{ range .Manifest.Global.Maintainers }} @{{ .Handle }}{{ end }}' "$f"
+            fi
+          done | tee "$GITHUB_WORKSPACE/oi-pr.maint"
+      - name: Generate Diff
         env:
           GITHUB_PR_NUMBER: ${{ github.event.pull_request.number }}
         run: |
           docker run --rm --read-only --tmpfs /tmp oisupport/bashbrew:diff-pr ./diff-pr.sh "$GITHUB_PR_NUMBER" | tee "$GITHUB_WORKSPACE/oi-pr.diff"
-          set +x
-          length="$(jq -Rcs 'length' "$GITHUB_WORKSPACE/oi-pr.diff")"
-          echo "::set-output name=length::$length"
       - name: Comment
         uses: actions/github-script@v3
         with:
@@ -99,8 +136,12 @@ jobs:
             }
             if (needNewComment) {
               const fs = require('fs');
-              const diff = fs.readFileSync(process.env.GITHUB_WORKSPACE + '/oi-pr.diff');
-              const body = "<details>\n<summary>" + commentText + "</summary>\n\n```diff\n" + diff + "\n```\n\n</details>";
+              const diff = fs.readFileSync(process.env.GITHUB_WORKSPACE + '/oi-pr.diff').toString().trimEnd();
+              var body = "<details>\n<summary>" + commentText + "</summary>\n\n```diff\n" + diff + "\n```\n\n</details>";
+              const maint = fs.readFileSync(process.env.GITHUB_WORKSPACE + '/oi-pr.maint').toString().trimEnd();
+              if (maint.length > 0) {
+                body += "\n\nRelevant Maintainers:\n\n" + maint;
+              }
               await github.issues.createComment({
                 owner: context.repo.owner,
                 repo: context.repo.repo,
@@ -108,4 +149,3 @@ jobs:
                 body: body,
               });
             }
-        if: fromJSON(steps.diff.outputs.length) > 0

.github/workflows/naughty.sh

@@ -3,7 +3,7 @@ set -Eeuo pipefail
 
 if [ "$#" -eq 0 ]; then
 	git fetch --quiet https://github.com/docker-library/official-images.git master
-	changes="$(git diff --numstat FETCH_HEAD...HEAD -- library/ | cut -d$'\t' -f3-)"
+	changes="$(git diff --no-renames --name-only --diff-filter='d' FETCH_HEAD...HEAD -- library/)"
 	repos="$(xargs -rn1 basename <<<"$changes")"
 	set -- $repos
 fi

.github/workflows/test-pr.yml

@@ -33,6 +33,7 @@ jobs:
     runs-on: ubuntu-latest
     outputs:
       strategy: ${{ steps.generate-jobs.outputs.strategy }}
+      length: ${{ steps.generate-jobs.outputs.length }}
     steps:
       - uses: actions/checkout@v2
         with:
@@ -44,10 +45,13 @@ jobs:
           strategy="$(.github/workflows/generate.sh ~/bashbrew)"
           jq . <<<"$strategy" # sanity check / debugging aid
           echo "::set-output name=strategy::$strategy"
+          length="$(jq <<<"$strategy" -r '.matrix.include | length')"
+          echo "::set-output name=length::$length"
 
   test:
     needs: generate-jobs
-    strategy: ${{ fromJson(needs.generate-jobs.outputs.strategy) }}
+    strategy: ${{ fromJSON(needs.generate-jobs.outputs.strategy) }}
+    if: needs.generate-jobs.outputs.length > 0
     name: ${{ matrix.name }}
     runs-on: ${{ matrix.os }}
     steps:

diff-pr.sh

@@ -80,7 +80,7 @@ else
 fi
 
 if [ "$#" -eq 0 ]; then
-	images="$(git -C oi/library diff --name-only HEAD...pull -- .)"
+	images="$(git -C oi/library diff --no-renames --name-only HEAD...pull -- .)"
 	[ -n "$images" ] || exit 0
 	images="$(xargs -n1 basename <<<"$images")"
 	set -- $images