fix: use prior tag before target version when version tag exists

scripts/generate_notes.py

@@ -41,7 +41,15 @@ def run_git(args):
         return 1, "", str(e)
 
 
-def find_previous_tag(to_ref, tag_pattern):
+def find_previous_tag(to_ref, tag_pattern, version=""):
+    # 0. If a target version is provided (e.g. 1.8.0), check if tag v$VERSION already exists.
+    # If it does, the commits for this release start from the tag BEFORE v$VERSION:
+    if version:
+        target_tag = version if version.startswith("v") else f"v{version}"
+        code_prev, prev_tag, _ = run_git(["describe", "--tags", f"--match={tag_pattern}", "--abbrev=0", f"{target_tag}^"])
+        if code_prev == 0 and prev_tag:
+            return prev_tag
+
     # 1. Check if to_ref itself is tagged with an exact tag matching tag_pattern:
     if tag_pattern:
         code, stdout, _ = run_git(["describe", "--tags", f"--match={tag_pattern}", "--exact-match", to_ref])
@@ -72,12 +80,12 @@ def find_previous_tag(to_ref, tag_pattern):
     return None
 
 
-def collect_commits(from_ref, to_ref, tag_pattern, max_commits):
+def collect_commits(from_ref, to_ref, tag_pattern, max_commits, version=""):
     # Ensure tags are up-to-date
     run_git(["fetch", "--tags", "--prune"])
 
     if not from_ref:
-        from_ref = find_previous_tag(to_ref, tag_pattern)
+        from_ref = find_previous_tag(to_ref, tag_pattern, version)
 
     commits = ""
     if from_ref:
@@ -179,7 +187,7 @@ def query_llm(args, commits_text):
 
 def main():
     args = parse_args()
-    commits = collect_commits(args.from_ref, args.to_ref, args.tag_pattern, args.max_commits)
+    commits = collect_commits(args.from_ref, args.to_ref, args.tag_pattern, args.max_commits, args.version)
     
     if not commits:
         sys.stderr.write("[action-release-notes] No commits discovered; using fallback release notes.\n")