Denylist guard at commit time (pre-commit + commit-msg hooks); drop publish_snapshot

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JEAjUkQRrCYX5MZhWxdtj2

1 files changed, 158 insertions, 0 deletions

diff --git a/scripts/denylist_check.py b/scripts/denylist_check.py
new file mode 100755
index 0000000..08cf985
--- /dev/null
+++ b/scripts/denylist_check.py
@@ -0,0 +1,158 @@
+#!/usr/bin/env python3
+"""Denylist guard for a public repo: refuse private words in commits (git hooks in .githooks/).
+
+Usage: denylist_check.py staged | msg FILE | tree [REF]
+  staged    added lines + paths of the index (pre-commit hook)
+  msg FILE  commit message, '#' lines skipped (commit-msg hook)
+  tree      every tracked file of REF (default HEAD): manual audit
+
+Lists (merged): publish-denylist.local in the worktree top and in the main tree (git-ignored),
+plus every `git config denylist.file <path>` (e.g. a global list). Lines: `word` = case-insensitive
+substring; `!token` = exemption (a hit inside an occurrence of token does not count); `#` comments.
+Output names the place and `word #<line>` only, never the word. Exit 0 clean, 1 hits.
+No list at all → warning, exit 0. Bypass once: `git commit --no-verify`.
+Enable in a clone: `git config core.hooksPath .githooks`.
+"""
+import re
+import subprocess
+import sys
+from pathlib import Path
+
+NAME = "publish-denylist.local"
+
+
+def git(*args):
+    r = subprocess.run(["git", "-c", "core.quotePath=false", *args], capture_output=True)
+    if r.returncode:
+        raise SystemExit(f"denylist-check: git {args[0]} failed: {r.stderr.decode(errors='replace').strip()}")
+    return r.stdout.decode("utf-8", errors="replace")
+
+
+def parse(text):
+    """([(lineno, word lowercased)], [exempt token lowercased])."""
+    words, exempt = [], []
+    for n, line in enumerate(text.splitlines(), 1):
+        w = line.strip()
+        if not w or w.startswith("#"):
+            continue
+        if w.startswith("!"):
+            if w[1:]:
+                exempt.append(w[1:].lower())
+        else:
+            words.append((n, w.lower()))
+    return words, exempt
+
+
+def _exempt_spans(low, exempt):
+    spans = []
+    for t in exempt:
+        spans += [(m.start(), m.end()) for m in re.finditer(re.escape(t), low)]
+    return spans
+
+
+def hits(text, words, exempt):
+    """Line numbers (in the list) of words found in text outside exempted tokens."""
+    low = text.lower()
+    spans = None
+    out = []
+    for n, w in words:
+        for m in re.finditer(re.escape(w), low):
+            if spans is None:
+                spans = _exempt_spans(low, exempt)
+            if not any(a <= m.start() and m.end() <= b for a, b in spans):
+                out.append(n)
+                break
+    return out
+
+
+def load_lists():
+    """[(label, words, exempt)] of every existing list; label '' for the repo list."""
+    top = Path(git("rev-parse", "--show-toplevel").strip())
+    common = Path(git("rev-parse", "--path-format=absolute", "--git-common-dir").strip())
+    cands = [("", top / NAME), ("", common.parent / NAME)]
+    r = subprocess.run(["git", "config", "--get-all", "denylist.file"], capture_output=True, text=True)
+    cands += [(Path(p).name + " ", Path(p).expanduser()) for p in r.stdout.splitlines() if p.strip()]
+    seen, lists = set(), []
+    for label, p in cands:
+        if not p.is_file() or p.resolve() in seen:
+            continue
+        seen.add(p.resolve())
+        lists.append((label, *parse(p.read_text(errors="replace"))))
+    return lists
+
+
+def scan(items, lists):
+    """items = [(place, text)] → ['place: <label>word #n']; words in place (a path) masked as ***."""
+    allw = sorted({w for _, words, _ in lists for _, w in words}, key=len, reverse=True)
+    mask = re.compile("|".join(map(re.escape, allw)), re.I) if allw else None
+    out = []
+    for place, text in items:
+        for label, words, exempt in lists:
+            out += [f"{mask.sub('***', place)}: {label}word #{n}" for n in hits(text, words, exempt)]
+    return out
+
+
+def staged_items():
+    items, path, line = [], None, 0
+    for name in git("diff", "--cached", "--name-only", "-z", "--diff-filter=ACMR").split("\0"):
+        if name:
+            items.append((f"path {name}", name))
+    for raw in git("diff", "--cached", "-U0", "--no-color", "--no-ext-diff", "--diff-filter=ACMR").splitlines():
+        if raw.startswith("+++ "):
+            path = raw[6:] if raw.startswith("+++ b/") else raw[4:].strip('"')
+        elif raw.startswith("@@"):
+            m = re.match(r"@@ -\S+ \+(\d+)", raw)
+            line = int(m.group(1)) if m else 0
+        elif raw.startswith("+") and path:
+            items.append((f"{path}:{line}", raw[1:]))
+            line += 1
+    return items
+
+
+def msg_items(file):
+    text = Path(file).read_text(errors="replace")
+    items = []
+    for n, l in enumerate(text.splitlines(), 1):
+        if l.startswith("# ------------------------ >8"):
+            break
+        if not l.startswith("#"):
+            items.append((f"commit message:{n}", l))
+    return items
+
+
+def tree_items(ref):
+    items = []
+    for name in git("ls-tree", "-r", "-z", "--name-only", ref).split("\0"):
+        if not name:
+            continue
+        items.append((f"path {name}", name))
+        data = subprocess.run(["git", "cat-file", "blob", f"{ref}:{name}"], capture_output=True).stdout
+        if b"\0" in data[:8000]:
+            continue
+        for n, l in enumerate(data.decode("utf-8", errors="replace").splitlines(), 1):
+            items.append((f"{name}:{n}", l))
+    return items
+
+
+def main(argv):
+    if not argv or argv[0] not in ("staged", "msg", "tree") or (argv[0] == "msg" and len(argv) != 2):
+        print(__doc__.split("\n\n")[1], file=sys.stderr)
+        return 2
+    lists = load_lists()
+    if not lists:
+        print(f"denylist-check: warning: no {NAME} (nor denylist.file): nothing checked", file=sys.stderr)
+        return 0
+    mode = argv[0]
+    items = staged_items() if mode == "staged" else msg_items(argv[1]) if mode == "msg" \
+        else tree_items(argv[1] if len(argv) > 1 else "HEAD")
+    found = scan(items, lists)
+    if found:
+        print("denylist-check: private word found (fix, or `git commit --no-verify` if a false hit):",
+              file=sys.stderr)
+        print("\n".join(found), file=sys.stderr)
+        return 1
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv[1:]))