tools: add --commit flag to cut for targeting a specific commit

Allow specifying which commit to tag and archive when cutting a release,
rather than always using HEAD. The commit ref flows through to both
git tag and create-archives.sh's git archive call. When not specified,
both default to HEAD as before.

Assisted-by: OpenCode (Claude Opus 4.6)

tools/create-archives.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 # Creates source and vendor tarballs for chunkah.
 # Used by both release.py and Packit's create-archive action.
-# Usage: create-archives.sh <source-tarball> <vendor-tarball>
+# Usage: create-archives.sh <source-tarball> <vendor-tarball> [commit]
 #        create-archives.sh --outdir <outdir>
 set -euo pipefail
 shopt -s inherit_errexit
@@ -9,21 +9,23 @@ shopt -s inherit_errexit
 version=$(cargo metadata --no-deps --format-version=1 \
     | python3 -c 'import json,sys; print(json.load(sys.stdin)["packages"][0]["version"])')
 
+commit="HEAD"
 if [[ "${1:-}" == "--outdir" ]]; then
     outdir="${2:-.}"
     source_tarball="${outdir}/chunkah-${version}.tar.gz"
     vendor_tarball="${outdir}/chunkah-${version}-vendor.tar.gz"
-elif [[ $# -ne 2 ]]; then
-    echo "Usage: create-archives.sh <source-tarball> <vendor-tarball>" >&2
+elif [[ $# -lt 2 || $# -gt 3 ]]; then
+    echo "Usage: create-archives.sh <source-tarball> <vendor-tarball> [commit]" >&2
     echo "       create-archives.sh --outdir <outdir>" >&2
     exit 1
 else
     source_tarball="${1}"
     vendor_tarball="${2}"
+    commit="${3:-${commit}}"
 fi
 
 git archive --format=tar.gz "--prefix=chunkah-${version}/" \
-    -o "${source_tarball}" HEAD
+    -o "${source_tarball}" "${commit}"
 
 cargo vendor-filterer --platform '*-unknown-linux-gnu' --tier 2 \
     --format=tar.gz --prefix=vendor "${vendor_tarball}"

tools/release.py

@@ -41,12 +41,15 @@ def main():
     cut_parser.add_argument(
         "--notes-file", default=None,
         help="Path to release notes file (skips fetching and editing)")
+    cut_parser.add_argument(
+        "--commit", default=None,
+        help="Target commit to tag and archive (default: HEAD)")
     cut_parser.add_argument(
         "--no-push", action="store_true",
         help="Prepare release without pushing to remote")
     cut_parser.set_defaults(
         func=lambda args: cut_release(args.version, args.no_push,
-                                      args.notes_file))
+                                      args.notes_file, args.commit))
 
     args = parser.parse_args()
     args.func(args)
@@ -188,7 +191,8 @@ def generate_notes(version: str):
     sys.stdout.write(notes)
 
 
-def cut_release(version: str, no_push: bool, notes_file: str | None):
+def cut_release(version: str, no_push: bool, notes_file: str | None,
+                commit: str | None):
     """Cut a release for chunkah."""
     tag = f"v{version}"
     source_tarball = f"{NAME}-{version}.tar.gz"
@@ -239,10 +243,10 @@ def cut_release(version: str, no_push: bool, notes_file: str | None):
             saved_notes_file.write_text(edited_notes)
 
         step(f"Creating signed tag {tag}...")
-        create_signed_tag(tag, edited_notes)
+        create_signed_tag(tag, edited_notes, commit)
 
         step("Generating source and vendor tarballs...")
-        generate_archives(source_tarball, vendor_tarball)
+        generate_archives(source_tarball, vendor_tarball, commit)
 
         step("Verifying offline build...")
         verify_offline_build(version, source_tarball, vendor_tarball)
@@ -356,19 +360,26 @@ def edit_notes(initial: str) -> str:
         os.unlink(tmp_path)
 
 
-def create_signed_tag(tag: str, message: str):
+def create_signed_tag(tag: str, message: str, commit: str | None = None):
     """Create a signed annotated git tag."""
     with tempfile.NamedTemporaryFile(mode="w", suffix=".md") as f:
         f.write(message)
         f.flush()
         # Use a non-# commentchar so that markdown headers are preserved
-        run("git", "-c", "core.commentchar=;", "tag", "-s", "-a", tag,
-            "-F", f.name)
+        cmd = ["git", "-c", "core.commentchar=;", "tag", "-s", "-a", tag,
+               "-F", f.name]
+        if commit:
+            cmd.append(commit)
+        run(*cmd)
 
 
-def generate_archives(source_tarball: str, vendor_tarball: str):
+def generate_archives(source_tarball: str, vendor_tarball: str,
+                      commit: str | None = None):
     """Generate source and vendor tarballs using create-archives.sh."""
-    run("tools/create-archives.sh", source_tarball, vendor_tarball)
+    args = ["tools/create-archives.sh", source_tarball, vendor_tarball]
+    if commit:
+        args.append(commit)
+    run(*args)
 
 
 def verify_offline_build(version: str, source: str, vendor: str):