CNA-BUG-153: StorageContainer::DeleteFile removes an empty directory and DeleteDirectory removes a file

CNA snapshot 009d40f5  ·  Known Issues › Current bugs  ·  source links pinned to 009d40f5

Both methods call std::filesystem::remove on the resolved path without checking the entry type, so each deletes the other kind of entry, and a missing directory is a silent no-op where XNA throws.

Identifier

CNA-BUG-153

Category

Bug

Subsystem

Storage

Status

Open

Verified against

CNA 009d40f5 (009d40f5dd085c4e674d3479675fac84b12b3e0a)

Severity

Low (a triage suggestion, not a project priority)

Evidence basis

Source-verified: read at TARGET, not executed

Tests touching this area

Yes: see Current tests

Affected contract

Microsoft::Xna::Framework::Storage::StorageContainer::DeleteFile(const std::string&) and DeleteDirectory(const std::string&)

Expected behaviour

XNA 4.0 delegates to File.Delete and Directory.Delete (decompiled StorageContainer): the first refuses a directory, the second refuses a file and throws DirectoryNotFoundException for a missing directory. CNA's header documents DeleteFile as "Deletes a relative file" and DeleteDirectory as "Deletes a relative directory (must be empty)".

Actual behaviour at TARGET

After the containment check both methods in StorageContainer.cpp call fs::remove(ResolveNativePath(path)). DeleteFile("slot1") therefore removes an empty directory named slot1, DeleteDirectory("notes.txt") removes a file, a missing entry of either kind returns silently, and a non-empty directory throws std::filesystem::filesystem_error from either method.

Source locations

• modules/storage/src/StorageContainer.cpp — StorageContainer::DeleteFile and DeleteDirectory both call fs::remove
• modules/storage/include/Microsoft/Xna/Framework/Storage/StorageContainer.hpp — DeleteFile and DeleteDirectory documentation

Evidence

Checked by reading StorageContainer.cpp and its header at 009d40f5; not executed. The XNA behaviour is from the decompiled StorageContainer and the documented semantics of File.Delete/Directory.Delete. The candidate also noted GlobMatch's byte-wise ?; that part is published under CNA-BUG-047. The storage internals page records the type-blind deletes.

Focused reproduction

// Illustrative; not compiled or run for this entry.
container->CreateDirectory("slot1");
container->DeleteFile("slot1");          // removes the empty directory
auto note = container->CreateFile("notes.txt");
note.reset();
container->DeleteDirectory("notes.txt"); // removes the file
container->DeleteDirectory("missing");   // returns silently (XNA: DirectoryNotFoundException)

Current tests

StorageDeviceTests.cpp calls both methods only with escaping paths, to prove they are refused (ContainerOperationsRejectLexicalEscapes). Nothing checks the entry type or a missing entry.

Regression test

Tests that DeleteFile on a directory and DeleteDirectory on a file both throw and remove nothing, and that DeleteDirectory on a missing name throws; fix by checking is_regular_file/is_directory on the resolved native path first.

Blast radius

Cleanup code that deletes entries by name without knowing their type can remove a directory or file it did not mean to; code that relies on an exception for a missing directory never gets one. Deleting an existing entry of the right type behaves as documented.

Workaround

Check FileExists or DirectoryExists before deleting.