Harden list parser key-display fallbacks

Co-authored-by: Shri Sukhani <shrisukhani@users.noreply.github.com>

Author: cursoragent

hyperbrowser/client/managers/list_parsing_utils.py

@@ -6,6 +6,20 @@
 T = TypeVar("T")
 
 
+def _safe_key_display_for_error(
+    key: str,
+    *,
+    key_display: Callable[[str], str],
+) -> str:
+    try:
+        key_text = key_display(key)
+        if type(key_text) is not str:
+            raise TypeError("key display must be a string")
+        return key_text
+    except Exception:
+        return "<unreadable key>"
+
+
 def parse_mapping_list_items(
     items: List[Any],
     *,
@@ -41,8 +55,9 @@ def parse_mapping_list_items(
             except HyperbrowserError:
                 raise
             except Exception as exc:
+                key_text = _safe_key_display_for_error(key, key_display=key_display)
                 raise HyperbrowserError(
-                    f"Failed to read {item_label} object value for key '{key_display(key)}' at index {index}",
+                    f"Failed to read {item_label} object value for key '{key_text}' at index {index}",
                     original_error=exc,
                 ) from exc
         try:

tests/test_list_parsing_utils.py

@@ -102,6 +102,32 @@ def test_parse_mapping_list_items_wraps_value_read_failures():
     assert isinstance(exc_info.value.original_error, RuntimeError)
 
 
+def test_parse_mapping_list_items_falls_back_when_key_display_raises():
+    with pytest.raises(
+        HyperbrowserError,
+        match="Failed to read demo object value for key '<unreadable key>' at index 0",
+    ):
+        parse_mapping_list_items(
+            [_ExplodingValueMapping()],
+            item_label="demo",
+            parse_item=lambda payload: payload,
+            key_display=lambda key: 1 / 0,
+        )
+
+
+def test_parse_mapping_list_items_falls_back_when_key_display_returns_non_string():
+    with pytest.raises(
+        HyperbrowserError,
+        match="Failed to read demo object value for key '<unreadable key>' at index 0",
+    ):
+        parse_mapping_list_items(
+            [_ExplodingValueMapping()],
+            item_label="demo",
+            parse_item=lambda payload: payload,
+            key_display=lambda key: key.encode("utf-8"),
+        )
+
+
 def test_parse_mapping_list_items_wraps_parse_failures():
     with pytest.raises(
         HyperbrowserError,