fix(release-candidate): reuse a hotfix branch at its tip

.github/actions/RELEASE.md

@@ -185,9 +185,11 @@ candidate PR aimed at that branch). It still does not patch an older line
 that a higher tag has already passed.
 
 If an attempt fails after the branch was created — a broken `bump_command`,
-say — re-dispatching the same version and commit reuses the branch, because
-it is still sitting on exactly that commit with nothing merged into it. Any
-other mismatch is refused, and the branch has to be deleted by hand.
+say — re-dispatching the same version and commit reuses the branch. If
+hotfix PRs have already landed on it, propose sits on the tip (it does not
+reset to `base_commit`) and skips the version bump when the version file
+already reads the requested version. A branch that does not contain
+`base_commit` is refused.
 
 ## Installing it in a repository
 

.github/actions/release-candidate/README.md

@@ -47,8 +47,8 @@ Family: [Release pipeline](../RELEASE.md).
 1. Guard (propose) *(only if `inputs.stage == 'propose'`)*
 1. Cut the release branch at the base commit (propose) *(only if `inputs.stage == 'propose' && inputs.base_commit != ''`)*
 1. Bump version file *(only if `inputs.stage == 'propose'`)*
-1. Run bump command *(only if `inputs.stage == 'propose' && inputs.bump_command != ''`)*
-1. Draft changelog *(only if `inputs.stage == 'propose' && inputs.changelog_file != ''`)*
+1. Run bump command *(only if `inputs.stage == 'propose' && inputs.bump_command != '' && steps.bump.outputs.skipped != 'true'`)*
+1. Draft changelog *(only if `inputs.stage == 'propose' && inputs.changelog_file != '' && steps.bump.outputs.skipped != 'true'`)*
 1. Remove git auth before opening the PR *(only if `inputs.stage == 'propose'`)*
 1. Drop a stale candidate branch *(only if `inputs.stage == 'propose'`)*
 1. Open candidate PR — `peter-evans/create-pull-request` *(only if `inputs.stage == 'propose'`)*
@@ -66,6 +66,7 @@ Family: [Release pipeline](../RELEASE.md).
 - `base_commit $BASE_COMMIT is not a commit in this checkout; check the repository out with fetch-depth: 0`
 - `base_commit $base is not reachable from the default branch ($default); a release must ship code that landed on trunk`
 - `branch $branch already exists`
+- `branch $branch already exists at $existing, which does not contain base_commit $base`
 - `after bump_command, $FILE reads $actual, expected $NEW_VERSION`
 - `cut runs on a merged candidate PR (pull_request closed, merged == true)`
 - `candidate PR #$PR_NUMBER was opened by`

.github/actions/release-candidate/action.yml

@@ -214,21 +214,32 @@ runs:
           fi
           echo "base commit: $BASE_COMMIT -> $base"
         fi
-        # The release branch must not exist yet. One exception: with an
-        # explicit commit, propose creates that branch before it opens the PR,
-        # so a re-dispatch after a failed attempt finds its own branch still
-        # sitting on the requested commit, with nothing merged into it.
+        # The release branch must not exist yet, except with an explicit
+        # commit: propose creates it, so a re-dispatch may find it still on
+        # that commit, or already ahead with hotfix PRs. Sit on the tip in
+        # that case (do not reset to base_commit). A branch that does not
+        # contain base_commit is someone else's and is refused.
         existing="$(git ls-remote --heads origin "refs/heads/$branch" | cut -f1)"
+        checkout="$base"
         if [[ -n "$existing" ]]; then
-          if [[ -n "$base" && "$existing" == "$base" ]]; then
+          if [[ -z "$base" ]]; then
+            echo "::error::branch $branch already exists"; exit 1
+          fi
+          git fetch --quiet origin "+refs/heads/$branch:refs/remotes/origin/$branch"
+          if [[ "$existing" == "$base" ]]; then
             echo "::notice title=Reusing the release branch::$branch already exists at $base, from an earlier attempt at this candidate"
+          elif git merge-base --is-ancestor "$base" "$existing"; then
+            echo "::notice title=Reusing the release branch::$branch already has commits on top of $base; proposing from $existing"
+            checkout="$existing"
           else
-            echo "::error::branch $branch already exists"; exit 1
+            echo "::error::branch $branch already exists at $existing, which does not contain base_commit $base"
+            exit 1
           fi
         fi
         {
           echo "base=$base"
           echo "branch=$branch"
+          echo "checkout=$checkout"
         } >> "$GITHUB_OUTPUT"
 
     # With an explicit base commit the candidate PR cannot target the default
@@ -244,15 +255,19 @@ runs:
         GH_TOKEN: ${{ inputs.token }}
         BRANCH: ${{ steps.guard.outputs.branch }}
         BASE: ${{ steps.guard.outputs.base }}
+        CHECKOUT: ${{ steps.guard.outputs.checkout }}
       run: |
         set -euo pipefail
+        checkout="${CHECKOUT:-$BASE}"
         if ! git ls-remote --exit-code --heads origin "refs/heads/$BRANCH" >/dev/null; then
-          gh api "repos/$GITHUB_REPOSITORY/git/refs" -f ref="refs/heads/$BRANCH" -f sha="$BASE" >/dev/null
-          echo "created $BRANCH at $BASE"
+          gh api "repos/$GITHUB_REPOSITORY/git/refs" -f ref="refs/heads/$BRANCH" -f sha="$checkout" >/dev/null
+          echo "created $BRANCH at $checkout"
+        else
+          git fetch --quiet origin "+refs/heads/$BRANCH:refs/remotes/origin/$BRANCH"
         fi
-        git checkout --quiet -B "$BRANCH" "$BASE"
+        git checkout --quiet -B "$BRANCH" "$checkout"
         echo "release_branch=$BRANCH" >> "$GITHUB_OUTPUT"
-        echo "candidate PR will target $BRANCH"
+        echo "candidate PR will target $BRANCH at $checkout"
 
     - name: Bump version file
       if: inputs.stage == 'propose'
@@ -265,13 +280,21 @@ runs:
         TOOLS: ${{ github.action_path }}/../release-tools/release_tools.py
       run: |
         set -euo pipefail
-        old="$(python3 "$TOOLS" bump-file "$FILE" "$PATTERN" "$VERSION")"
+        old="$(python3 "$TOOLS" read-file "$FILE" "$PATTERN")"
+        if [[ "$old" == "$VERSION" ]]; then
+          echo "old=$old" >> "$GITHUB_OUTPUT"
+          echo "skipped=true" >> "$GITHUB_OUTPUT"
+          echo "$FILE already $VERSION; skipping bump"
+          exit 0
+        fi
+        python3 "$TOOLS" bump-file "$FILE" "$PATTERN" "$VERSION" >/dev/null
         echo "old=$old" >> "$GITHUB_OUTPUT"
+        echo "skipped=false" >> "$GITHUB_OUTPUT"
         echo "$FILE: $old -> $VERSION"
         git diff --stat
 
     - name: Run bump command
-      if: inputs.stage == 'propose' && inputs.bump_command != ''
+      if: inputs.stage == 'propose' && inputs.bump_command != '' && steps.bump.outputs.skipped != 'true'
       shell: bash
       env:
         OLD_VERSION: ${{ steps.bump.outputs.old }}
@@ -292,7 +315,7 @@ runs:
         git diff --stat
 
     - name: Draft changelog
-      if: inputs.stage == 'propose' && inputs.changelog_file != ''
+      if: inputs.stage == 'propose' && inputs.changelog_file != '' && steps.bump.outputs.skipped != 'true'
       id: changelog
       shell: bash
       env:

.github/workflows/actions-test.yml

@@ -682,10 +682,38 @@ jobs:
           base="$(cat "$RUNNER_TEMP/base")"
           guard 1.1.0 "$base"
           expect_output "base=$base"
+          expect_output "checkout=$base"
           refuse 1.1.0 "origin/main~1" "already exists"
           refuse 1.1.0 "" "already exists"
           echo "the same commit is reused; a different one, and the trunk flow, are refused"
 
+      - name: A hotfix branch that already moved is reused at its tip
+        run: |
+          set -euo pipefail
+          source "$SH/helpers.sh"
+          base="$(cat "$RUNNER_TEMP/base")"
+          git -C "$REPO" checkout --quiet release-v1.1.0
+          git -C "$REPO" commit --quiet --allow-empty -m "fix: already on the release branch"
+          git -C "$REPO" push --quiet origin release-v1.1.0
+          tip="$(git -C "$REPO" rev-parse HEAD)"
+          git -C "$REPO" checkout --quiet main
+          guard 1.1.0 "$base"
+          expect_output "base=$base"
+          expect_output "checkout=$tip"
+          : > "$OUT"
+          ( cd "$REPO" && env \
+              GH_TOKEN=fake \
+              GITHUB_REPOSITORY=megaeth-labs/fake \
+              GITHUB_OUTPUT="$OUT" \
+              BRANCH=release-v1.1.0 \
+              BASE="$base" \
+              CHECKOUT="$tip" \
+              bash "$SH/cut-branch.sh" )
+          expect_output "release_branch=release-v1.1.0"
+          [[ "$(git -C "$REPO" rev-parse HEAD)" == "$tip" ]] \
+            || { echo "HEAD was reset to the base commit, dropping hotfix commits"; exit 1; }
+          echo "propose sits on $tip, not $base"
+
   # The generated parts of every action README (inputs, outputs, steps,
   # errors) and the catalogue come from action.yml; stale docs fail here.
   docs: