fix: address PR comments

test_unstructured/documents/test_elements.py

@@ -16,6 +16,7 @@
     Element,
     ElementMetadata,
     NoID,
+    RegexMetadata,
     Text,
 )
 
@@ -189,6 +190,24 @@ def test_element_to_dict():
     assert element.to_dict() == expected
 
 
+def test_regex_metadata_round_trips_through_JSON():
+    """metadata.regex_metadata should appear at full depth in JSON."""
+    regex_metadata = {
+        "mail-stop": [RegexMetadata(text="MS-107", start=18, end=24)],
+        "version": [
+            RegexMetadata(text="current=v1.7.2", start=7, end=21),
+            RegexMetadata(text="supersedes=v1.7.2", start=22, end=40),
+        ],
+    }
+    metadata = ElementMetadata(regex_metadata=regex_metadata)
+
+    metadata_json = json.dumps(metadata.to_dict())
+    deserialized_metadata = ElementMetadata.from_dict(json.loads(metadata_json))
+    reserialized_metadata_json = json.dumps(deserialized_metadata.to_dict())
+
+    assert reserialized_metadata_json == metadata_json
+
+
 def test_metadata_from_dict_extra_fields():
     """
     Assert that the metadata classes ignore nonexistent fields.

unstructured/chunking/title.py

@@ -1,4 +1,4 @@
-"""Implementation of chunking.
+"""Implementation of chunking by title.
 
 Main entry point is the `@add_chunking_strategy()` decorator.
 """
@@ -133,7 +133,6 @@ def chunk_by_title(
                     value = cast(List[Any], value)
                     # -- get existing (list) value from chunk_metadata --
                     _value = getattr(metadata, attr, []) or []
-                    # TODO: this mutates the original, work on a copy instead.
                     _value.extend(item for item in value if item not in _value)
                     setattr(metadata, attr, _value)