fix(converter): cap doc_name length to avoid Windows path-length errors

Author: Sebastian Braun

openkb/converter.py

@@ -48,11 +48,24 @@ def _registry_path(path: Path, kb_dir: Path) -> str:
 
 _SAFE_STEM_RE = re.compile(r"[^\w\-]+")
 _SUFFIX_LEN = 8
+_MAX_STEM_LEN = 40
 
 
 def _sanitize_stem(stem: str) -> str:
+    """Sanitize and cap ``stem``, appending a hash suffix if truncated.
+
+    ``doc_name`` (this function's return value) can appear twice in the
+    per-add staging path (staging dir name + images subdir), so an
+    unbounded stem risks Windows' ~260-char path limit. The suffix is a
+    hash of the FULL cleaned stem (not just the truncated prefix) so two
+    different overlong stems sharing the same prefix don't collide.
+    """
     normalized = unicodedata.normalize("NFKC", stem)
-    return _SAFE_STEM_RE.sub("-", normalized).strip("-") or "document"
+    cleaned = _SAFE_STEM_RE.sub("-", normalized).strip("-") or "document"
+    if len(cleaned) > _MAX_STEM_LEN:
+        digest = hashlib.sha256(cleaned.encode("utf-8")).hexdigest()[:_SUFFIX_LEN]
+        cleaned = f"{cleaned[:_MAX_STEM_LEN].rstrip('-')}-{digest}"
+    return cleaned
 
 
 def _name_taken(candidate: str, registry: HashRegistry) -> bool:

tests/test_converter.py

@@ -217,6 +217,40 @@ def test_outside_kb_is_absolute_posix(self, kb_dir, tmp_path_factory):
         assert result.startswith("/")
 
 
+# ---------------------------------------------------------------------------
+# _sanitize_stem
+# ---------------------------------------------------------------------------
+
+
+class TestSanitizeStem:
+    def test_short_stem_is_unchanged(self):
+        from openkb.converter import _sanitize_stem
+
+        assert _sanitize_stem("report") == "report"
+
+    def test_long_stem_is_capped_with_hash_suffix(self):
+        from openkb.converter import _MAX_STEM_LEN, _sanitize_stem
+
+        stem = "bulkQuery_result_" + "a" * 60
+        result = _sanitize_stem(stem)
+        assert len(result) == _MAX_STEM_LEN + 1 + 8  # prefix + "-" + 8-hex digest
+        assert result.startswith(stem[:_MAX_STEM_LEN])
+
+    def test_long_stem_truncation_is_deterministic(self):
+        from openkb.converter import _sanitize_stem
+
+        stem = "x" * 100
+        assert _sanitize_stem(stem) == _sanitize_stem(stem)
+
+    def test_different_long_stems_with_same_prefix_do_not_collide(self):
+        from openkb.converter import _MAX_STEM_LEN, _sanitize_stem
+
+        prefix = "a" * _MAX_STEM_LEN
+        first = _sanitize_stem(prefix + "-one")
+        second = _sanitize_stem(prefix + "-two")
+        assert first != second
+
+
 # ---------------------------------------------------------------------------
 # resolve_doc_name
 # ---------------------------------------------------------------------------