respect kwargs spacing

Author: djsaunde

.pre-commit-config.yaml

@@ -7,3 +7,10 @@ repos:
           - --fix
           - --exit-non-zero-on-fix
       - id: ruff-format
+  - repo: local
+    hooks:
+      - id: enforce-kwargs-spacing
+        name: Enforce spaces around keyword equals
+        entry: scripts/enforce_kwargs_spacing.py
+        language: system
+        types: [python]

scripts/enforce_kwargs_spacing.py

@@ -0,0 +1,100 @@
+#!/usr/bin/env python3
+"""Ensure keyword arguments use spaces around '=' (e.g., foo = bar)."""
+
+from __future__ import annotations
+
+import argparse
+import io
+import sys
+import tokenize
+from collections import defaultdict
+from pathlib import Path
+
+
+def enforce_spacing(text: str) -> tuple[str, bool]:
+    """Return updated text with keyword '=' padded by spaces, plus change flag."""
+    lines = text.splitlines(keepends = True)
+    if not lines:
+        return text, False
+
+    offsets: dict[int, int] = defaultdict(int)
+    changed = False
+
+    reader = io.StringIO(text).readline
+    for token in tokenize.generate_tokens(reader):
+        if token.type != tokenize.OP or token.string != "=":
+            continue
+
+        line_index = token.start[0] - 1
+        col = token.start[1] + offsets[line_index]
+
+        if line_index < 0 or line_index >= len(lines):
+            continue
+
+        line = lines[line_index]
+        if col >= len(line) or line[col] != "=":
+            continue
+
+        line_changed = False
+
+        # Insert a space before '=' when missing and not preceded by whitespace.
+        if col > 0 and line[col - 1] not in {" ", "\t"}:
+            line = f"{line[:col]} {line[col:]}"
+            offsets[line_index] += 1
+            col += 1
+            line_changed = True
+            changed = True
+
+        # Insert a space after '=' when missing and not followed by whitespace or newline.
+        next_index = col + 1
+        if next_index < len(line) and line[next_index] not in {" ", "\t", "\n", "\r"}:
+            line = f"{line[:next_index]} {line[next_index:]}"
+            offsets[line_index] += 1
+            line_changed = True
+            changed = True
+
+        if line_changed:
+            lines[line_index] = line
+
+    if not changed:
+        return text, False
+
+    return "".join(lines), True
+
+
+def process_file(path: Path) -> bool:
+    try:
+        with tokenize.open(path) as handle:
+            original = handle.read()
+            encoding = handle.encoding
+    except (OSError, SyntaxError) as exc:  # SyntaxError from tokenize on invalid python
+        print(f"Failed to read {path}: {exc}", file = sys.stderr)
+        return False
+
+    updated, changed = enforce_spacing(original)
+    if changed:
+        path.write_text(updated, encoding = encoding)
+    return changed
+
+
+def main(argv: list[str]) -> int:
+    parser = argparse.ArgumentParser(description = __doc__)
+    parser.add_argument("files", nargs = "+", help = "Python files to fix")
+    args = parser.parse_args(argv)
+
+    touched: list[Path] = []
+    for entry in args.files:
+        path = Path(entry)
+        if not path.exists() or path.is_dir():
+            continue
+        if process_file(path):
+            touched.append(path)
+
+    if touched:
+        for path in touched:
+            print(f"Adjusted kwarg spacing in {path}")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv[1:]))