Python: preserve Unicode paths in in-memory file discovery

python/packages/core/agent_framework/_harness/_file_access.py

@@ -1113,6 +1113,7 @@ async def list_children(self, directory: str = "") -> list[FileStoreEntry]:
         prefix = _normalize_relative_path(directory, is_directory=True).lower()
         if prefix and not prefix.endswith("/"):
             prefix += "/"
+        prefix_depth = prefix.count("/")
         async with self._lock:
             entries = [(key, display) for key, (display, _) in self._files.items()]
         files: list[str] = []
@@ -1121,18 +1122,18 @@ async def list_children(self, directory: str = "") -> list[FileStoreEntry]:
         for key, display in entries:
             if not key.startswith(prefix):
                 continue
-            remainder = key[len(prefix) :]
-            separator_index = remainder.find("/")
-            if separator_index == -1:
-                # ``display`` is the original-case normalized path; strip the
-                # directory prefix using the same length we matched on ``key``.
-                files.append(display[len(prefix) :])
-            elif separator_index > 0:
-                segment_key = remainder[:separator_index]
+            # Unicode lowercasing can change character counts, so key offsets
+            # cannot be used to slice the original display path.
+            remainder = display.split("/", prefix_depth)[-1]
+            segment, separator, _ = remainder.partition("/")
+            if not separator:
+                files.append(remainder)
+            elif segment:
+                segment_key = segment.lower()
                 if segment_key in seen_dirs:
                     continue
                 seen_dirs.add(segment_key)
-                directories.append(display[len(prefix) : len(prefix) + separator_index])
+                directories.append(segment)
         results: list[FileStoreEntry] = [FileStoreEntry(name, FileStoreEntry.DIRECTORY) for name in directories]
         results.extend(FileStoreEntry(name, FileStoreEntry.FILE) for name in files)
         return results
@@ -1165,6 +1166,7 @@ async def search(
         prefix = _normalize_relative_path(directory, is_directory=True).lower()
         if prefix and not prefix.endswith("/"):
             prefix += "/"
+        prefix_depth = prefix.count("/")
         search_pattern = _compile_search_regex(regex_pattern)
 
         async with self._lock:
@@ -1178,7 +1180,7 @@ def scan() -> list[FileSearchResult]:
                 relative_key = key[len(prefix) :]
                 if not recursive and "/" in relative_key:
                     continue
-                relative_display = display[len(prefix) :]
+                relative_display = display.split("/", prefix_depth)[-1]
                 if not _matches_glob(relative_display, glob_pattern):
                     continue
                 result = AgentFileStore.scan_content(relative_display, file_content, search_pattern)

python/packages/core/tests/core/test_harness_file_access.py

@@ -175,6 +175,38 @@ async def test_in_memory_store_round_trips_files() -> None:
     assert sorted(await _list_files(store)) == []
 
 
+@pytest.mark.parametrize("directory", ["İstanbul", "i\u0307stanbul", "İSTANBUL/"])
+async def test_in_memory_store_lists_unicode_paths_without_truncation(directory: str) -> None:
+    """Length-changing lowercasing must not alter the displayed path components."""
+    store = InMemoryAgentFileStore()
+    await store.write("İstanbul/Notes.md", "memory")
+    await store.write("İstanbul/İzmir/plan.md", "nested memory")
+    await store.write("i\u0307stanbul/i\u0307zmir/other.md", "another memory")
+
+    assert await _list_dirs(store) == ["İstanbul"]
+    assert await _list_files(store, directory) == ["Notes.md"]
+    assert await _list_dirs(store, directory) == ["İzmir"]
+    assert sorted(await _list_files(store, f"{directory.rstrip('/')}/İzmir")) == ["other.md", "plan.md"]
+    assert await store.read(f"{directory.rstrip('/')}/notes.MD") == "memory"
+
+
+@pytest.mark.parametrize("directory", ["İstanbul", "i\u0307stanbul", "İSTANBUL/"])
+async def test_in_memory_store_search_preserves_unicode_relative_paths(directory: str) -> None:
+    """Search results must retain readable paths after matching a Unicode directory."""
+    store = InMemoryAgentFileStore()
+    await store.write("İstanbul/Notes.md", "memory")
+    await store.write("İstanbul/İzmir/plan.md", "memory")
+    await store.write("other/notes.md", "memory")
+
+    direct = await store.search(directory, "memory", "Notes.md")
+    assert [result.file_name for result in direct] == ["Notes.md"]
+
+    recursive = await store.search(directory, "memory", recursive=True)
+    assert {result.file_name for result in recursive} == {"Notes.md", "İzmir/plan.md"}
+    for result in recursive:
+        assert await store.read(f"{directory.rstrip('/')}/{result.file_name}") == "memory"
+
+
 async def test_in_memory_store_search_returns_matches_with_snippets() -> None:
     """The in-memory store should search file content case-insensitively and respect glob filters."""
     store = InMemoryAgentFileStore()