tools (volt): doc_census_check -- a --tools filter that matches nothing is rc 2, not '0 tools scanned' + rc 0; 35 cells

tools/doc_census_check.py

@@ -123,7 +123,7 @@ SCOPE, STATED RATHER THAN IMPLIED
 
 USAGE
   python3 doc_census_check.py [--repo DIR] [--rev HEAD] [--tools NAME...]
-      [--json OUT] [--no-run] [--selftest]   # selftest: 33 cells, one per claim class
+      [--json OUT] [--no-run] [--selftest]   # selftest: 35 cells, one per claim class
 """
 import argparse
 import ast
@@ -625,6 +625,14 @@ def _fixture_checks():
           counts({**synthetic, "selftest_leg": False})[4],
           ["no --selftest: leg 2 absent"])
 
+    # --tools: a filter that matches nothing must not read as a clean scan.
+    check("tools: a bare basename is reported missing, not scanned as zero",
+          resolve_tools(["checkin_check.py"], {"tools/checkin_check.py"}),
+          (["checkin_check.py"], ["checkin_check.py"]))
+    check("tools: no filter means every tracked tool and nothing missing",
+          resolve_tools(None, {"tools/b.py", "tools/a.py", "README.md"}),
+          (["tools/a.py", "tools/b.py"], []))
+
     print(f"selftest: {cells[0]} cells, {cells[0] - bad[0]} passed, {bad[0]} failed")
     return 0 if ok else 1
 
@@ -872,6 +880,17 @@ def counts(rep):
             len(rep["verdicts"]), notes)
 
 
+def resolve_tools(requested, tree):
+    """(tools, missing). A requested name that is not tracked at the rev is
+    REPORTED, never silently dropped: `--tools checkin_check.py` (a bare
+    basename instead of a repo-relative path) scanned zero tools and exited 0,
+    which reads exactly like a clean pass. Measured 2026-10-18 at 8932d06."""
+    if not requested:
+        return sorted(p for p in tree
+                      if p.startswith("tools/") and p.endswith(".py")), []
+    return list(requested), [t for t in requested if t not in tree]
+
+
 def main():
     ap = argparse.ArgumentParser(description=__doc__,
                                  formatter_class=argparse.RawDescriptionHelpFormatter)
@@ -889,11 +908,16 @@ def main():
 
     store = git(a.repo, "ls-tree", "-r", "--name-only", a.rev)
     tree = {p for p in store.decode("utf-8", "replace").split("\n") if p}
-    tools = a.tools or sorted(p for p in tree
-                              if p.startswith("tools/") and p.endswith(".py"))
+    tools, missing = resolve_tools(a.tools, tree)
     if not tools:
         print(f"no tools found at {a.rev}", file=sys.stderr)
         return 2
+    if missing:
+        print(f"cannot grade: --tools names nothing tracked at {a.rev}: "
+              f"{', '.join(missing)}", file=sys.stderr)
+        print("  names are repo-relative, e.g. --tools tools/checkin_check.py; "
+              "a filter that matches nothing is not a clean scan", file=sys.stderr)
+        return 2
 
     cache, reports = {}, []
     with tempfile.TemporaryDirectory(prefix="doccensus-") as tmpdir: