feat: add source-dir and repo-url inputs for external repo support

Allow changelog generation from upstream repositories instead of only
the current working directory. Supports packaging repos that contain
only rpm spec files while the source lives in an external git repo.

- source-dir: point at an existing local checkout
- repo-url: action clones a bare copy automatically
- source-dir takes precedence if both are set

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

README.md

@@ -24,7 +24,8 @@ since the last release.
 
 ## Requirements
 
-The consumer workflow must check out the repo with full git history:
+When collecting commits from the current repo (default), the consumer
+workflow must check out with full git history:
 
 ```yaml
 - uses: actions/checkout@v4
@@ -35,6 +36,10 @@ The consumer workflow must check out the repo with full git history:
 Without this, `git describe` can't see prior tags and the entry will
 default to "No user-visible changes" on every release.
 
+When using `repo-url`, the action handles cloning automatically.
+When using `source-dir`, ensure the checkout at that path has full
+history (`fetch-depth: 0`).
+
 ## Inputs
 
 | Input              | Required | Default                                       | Description                                                                 |
@@ -45,6 +50,8 @@ default to "No user-visible changes" on every release.
 | `author`           | no       | `Gitea Actions <actions@git.lair.cafe>`       | Name and email for the entry.                                               |
 | `tag-pattern`      | no       | `v*`                                          | Glob pattern for release tags, used to locate the previous release.         |
 | `exclude-patterns` | no       | (see below)                                   | Newline-separated `grep -E` patterns to drop from the generated log.        |
+| `source-dir`       | no       | —                                             | Path to a local git checkout to collect commits from instead of `$PWD`.      |
+| `repo-url`         | no       | —                                             | URL of an external repo to clone (bare) for commit history.                 |
 
 Default `exclude-patterns`:
 
@@ -86,6 +93,52 @@ Note the fully-qualified URL in `uses:` — the Gitea instance's
 `DEFAULT_ACTIONS_URL` points at github.com, so internal actions must
 be referenced by absolute URL.
 
+### Packaging repo that tracks an upstream source
+
+When your internal repo only contains rpm packaging (spec file, patches,
+etc.) and the actual source lives in an external git repository, use
+`repo-url` to pull commit history from upstream:
+
+```yaml
+jobs:
+  srpm:
+    runs-on: fedora
+    if: startsWith(github.ref, 'refs/tags/v')
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Determine version
+        id: version
+        run: echo "VERSION=${GITHUB_REF#refs/tags/v}" >> "$GITHUB_OUTPUT"
+
+      - name: Update changelog from upstream
+        uses: https://git.lair.cafe/actions/rpm-changelog@v1
+        with:
+          spec: mypackage.spec
+          version: ${{ steps.version.outputs.VERSION }}
+          repo-url: https://github.com/upstream-org/upstream-repo.git
+```
+
+Alternatively, if your workflow already clones the upstream source (e.g.
+to build a tarball), point `source-dir` at the existing checkout to
+avoid cloning twice:
+
+```yaml
+      - name: Clone upstream source
+        run: git clone https://github.com/upstream-org/upstream-repo.git /tmp/upstream
+
+      - name: Update changelog from local clone
+        uses: https://git.lair.cafe/actions/rpm-changelog@v1
+        with:
+          spec: mypackage.spec
+          version: ${{ steps.version.outputs.VERSION }}
+          source-dir: /tmp/upstream
+```
+
+If both `source-dir` and `repo-url` are set, `source-dir` wins.
+`repo-url` clones are bare with `--filter=blob:none` to minimise
+bandwidth — only commit/tag metadata is fetched.
+
 ## Versioning
 
 Pin to a major version tag (`@v1`) for automatic patch/minor updates.

action.yml

@@ -44,6 +44,22 @@ inputs:
     default: |
       ^- chore: bump version
       ^- Merge
+  source-dir:
+    description: >
+      Path to a local git checkout to collect commits from, instead
+      of the current working directory. Useful when your packaging
+      repo is separate from the upstream source repo and you have
+      already cloned the source elsewhere in the workflow.
+    required: false
+    default: ''
+  repo-url:
+    description: >
+      URL of an external git repository to collect commits from.
+      The action will clone (bare, tags-only) this repo into a
+      temporary directory and read its history. Mutually exclusive
+      with source-dir — if both are set, source-dir wins.
+    required: false
+    default: ''
 
 runs:
   using: composite
@@ -57,6 +73,8 @@ runs:
         CHANGELOG_AUTHOR: ${{ inputs.author }}
         TAG_PATTERN: ${{ inputs.tag-pattern }}
         EXCLUDE_PATTERNS: ${{ inputs.exclude-patterns }}
+        SOURCE_DIR: ${{ inputs.source-dir }}
+        REPO_URL: ${{ inputs.repo-url }}
       run: |
         bash "${{ github.action_path }}/scripts/generate-rpm-changelog.sh" \
           "$SPEC" "$VERSION"

scripts/generate-rpm-changelog.sh

@@ -9,6 +9,12 @@
 #   RELEASE           — release suffix, default "1"
 #   TAG_PATTERN       — glob for release tags, default "v*"
 #   EXCLUDE_PATTERNS  — newline-separated grep -E patterns to drop
+#   SOURCE_DIR        — path to an external git checkout to read history from
+#   REPO_URL          — URL of a remote repo to clone (bare) for history
+#
+# If SOURCE_DIR or REPO_URL is set, commits are collected from that
+# repository instead of the current working directory. SOURCE_DIR
+# takes precedence over REPO_URL.
 #
 # Collects commits since the previous matching tag, drops filtered
 # lines (bump-version chore commits, merges, etc.), and writes a
@@ -22,6 +28,35 @@ AUTHOR="${CHANGELOG_AUTHOR:-Gitea Actions <actions@git.lair.cafe>}"
 RELEASE="${RELEASE:-1}"
 TAG_PATTERN="${TAG_PATTERN:-v*}"
 EXCLUDE_PATTERNS="${EXCLUDE_PATTERNS:-$'^- chore: bump version\n^- Merge'}"
+SOURCE_DIR="${SOURCE_DIR:-}"
+REPO_URL="${REPO_URL:-}"
+
+# Resolve the git directory to collect commits from.
+# Priority: SOURCE_DIR > REPO_URL > current working directory.
+CLEANUP_DIR=""
+GIT_ARGS=()
+
+if [ -n "$SOURCE_DIR" ]; then
+  if [ ! -d "$SOURCE_DIR/.git" ] && ! git -C "$SOURCE_DIR" rev-parse --git-dir >/dev/null 2>&1; then
+    printf 'error: source-dir is not a git repository: %s\n' "$SOURCE_DIR" >&2
+    exit 1
+  fi
+  GIT_ARGS=(-C "$SOURCE_DIR")
+  printf 'Using source-dir for commit history: %s\n' "$SOURCE_DIR"
+elif [ -n "$REPO_URL" ]; then
+  CLONE_DIR=$(mktemp -d)
+  CLEANUP_DIR="$CLONE_DIR"
+  printf 'Cloning %s (bare) for commit history…\n' "$REPO_URL"
+  git clone --bare --filter=blob:none "$REPO_URL" "$CLONE_DIR/repo.git"
+  GIT_ARGS=(-C "$CLONE_DIR/repo.git")
+fi
+
+cleanup() {
+  if [ -n "$CLEANUP_DIR" ] && [ -d "$CLEANUP_DIR" ]; then
+    rm -rf "$CLEANUP_DIR"
+  fi
+}
+trap cleanup EXIT
 
 if [ ! -f "$SPEC" ]; then
   echo "error: spec file not found: $SPEC" >&2
@@ -34,10 +69,10 @@ if ! grep -q '^%changelog' "$SPEC"; then
 fi
 
 # Find the previous release tag (exclude the current tag at HEAD).
-PREV_TAG=$(git describe --tags --abbrev=0 --match="$TAG_PATTERN" HEAD^ 2>/dev/null || echo "")
+PREV_TAG=$(git "${GIT_ARGS[@]}" describe --tags --abbrev=0 --match="$TAG_PATTERN" HEAD^ 2>/dev/null || echo "")
 
 if [ -n "$PREV_TAG" ]; then
-  RAW=$(git log --no-merges --pretty=format:'- %s' "${PREV_TAG}..HEAD")
+  RAW=$(git "${GIT_ARGS[@]}" log --no-merges --pretty=format:'- %s' "${PREV_TAG}..HEAD")
 
   # Build a combined grep -E pattern from the exclude list; drop blanks.
   COMBINED=""