COMP: Python commit message update

.pre-commit-config.yaml

@@ -102,7 +102,7 @@ repos:
       stages: [pre-commit]
     - id: kw-commit-msg
       name: 'kw commit-msg'
-      entry: 'Utilities/Hooks/kw-commit-msg'
+      entry: 'Utilities/Hooks/kw-commit-msg.py'
       language: system
       stages: [commit-msg]
       exclude: "\\/ThirdParty\\/"

Utilities/Hooks/kw-commit-msg.py

@@ -0,0 +1,134 @@
+#!/usr/bin/env python3
+import os
+import sys
+import subprocess
+import re
+
+from pathlib import Path
+import textwrap
+
+DEFAULT_LINE_LENGTH: int = 78
+
+
+def die(message, commit_msg_path):
+    print("commit-msg hook failure", file=sys.stderr)
+    print("-----------------------", file=sys.stderr)
+    print(message, file=sys.stderr)
+    print("-----------------------", file=sys.stderr)
+    print(
+        f"""
+To continue editing, run the command
+  git commit -e -F "{commit_msg_path}"
+(assuming your working directory is at the top).""",
+        file=sys.stderr,
+    )
+    sys.exit(1)
+
+
+def get_max_length():
+    try:
+        result = subprocess.run(
+            ["git", "config", "--get", "hooks.commit-msg.ITKCommitSubjectMaxLength"],
+            capture_output=True,
+            text=True,
+            check=True,
+        )
+    except subprocess.CalledProcessError as _:
+        return DEFAULT_LINE_LENGTH
+
+
+def main():
+    git_dir_path: Path = Path(os.environ.get("GIT_DIR", ".git")).resolve()
+    commit_msg_path: Path = git_dir_path / "COMMIT_MSG"
+
+    if len(sys.argv) < 2:
+        die(f"Usage: {sys.argv[0]} <git_commit_message_file>", commit_msg_path)
+
+    input_file: Path = Path(sys.argv[1])
+    if not input_file.exists():
+        die(
+            f"Missing input_file {sys.argv[1]} for {sys.argv[0]} processing",
+            commit_msg_path,
+        )
+    max_subjectline_length: int = get_max_length()
+
+    original_input_file_lines: list[str] = []
+    with open(input_file) as f_in:
+        original_input_file_lines = f_in.readlines()
+
+    input_file_lines: list[str] = []
+    for test_line in original_input_file_lines:
+        test_line = test_line.strip()
+        is_empty_line_before_subject: bool = (
+            len(input_file_lines) == 0 and len(test_line) == 0
+        )
+        if test_line.startswith("#") or is_empty_line_before_subject:
+            continue
+        input_file_lines.append(f"{test_line}\n")
+
+    with open(commit_msg_path, "w") as f_out:
+        f_out.writelines(input_file_lines)
+
+    subject_line: str = input_file_lines[0]
+
+    if len(subject_line) < 8:
+        die(
+            f"The first line must be at least 8 characters:\n--------\n{subject_line}\n--------",
+            commit_msg_path,
+        )
+    if (
+        len(subject_line) > max_subjectline_length
+        and not subject_line.startswith("Merge ")
+        and not subject_line.startswith("Revert ")
+    ):
+        die(
+            f"The first line may be at most {max_subjectline_length} characters:\n"
+            + "-" * max_subjectline_length
+            + f"\n{subject_line}\n"
+            + "-" * max_subjectline_length,
+            commit_msg_path,
+        )
+    if re.match(r"^[ \t]|[ \t]$", subject_line):
+        die(
+            f"The first line may not have leading or trailing space:\n[{subject_line}]",
+            commit_msg_path,
+        )
+    if not re.match(
+        r"^(Merge|Revert|BUG:|COMP:|DOC:|ENH:|PERF:|STYLE:|WIP:)\s", subject_line
+    ):
+        die(
+            f"""Start ITK commit messages with a standard prefix (and a space):
+  BUG:    - fix for runtime crash or incorrect result
+  COMP:   - compiler error or warning fix
+  DOC:    - documentation change
+  ENH:    - new functionality
+  PERF:   - performance improvement
+  STYLE:  - no logic impact (indentation, comments)
+  WIP:    - Work In Progress not ready for merge
+To reference GitHub issue XXXX, add "Issue #XXXX" to the commit message.
+If the issue addresses an open issue, add "Closes #XXXX" to the message.""",
+            commit_msg_path,
+        )
+    if re.match(r"^BUG: [0-9]+\.", subject_line):
+        die(
+            f'Do not put a "." after the bug number:\n\n  {subject_line}',
+            commit_msg_path,
+        )
+    del subject_line
+
+    if len(input_file_lines) > 1:
+        second_line: str = input_file_lines[
+            1
+        ].strip()  # Remove whitespace at begining and end
+        if len(second_line) == 0:
+            input_file_lines[1] = "\n"  # Replace line with only newline
+        else:
+            die(
+                f'The second line of the commit message must be empty:\n"{second_line}" with length {len(second_line)}',
+                commit_msg_path,
+            )
+        del second_line
+
+
+if __name__ == "__main__":
+    main()