[JoseZamoraCifras]

Fix or feature

• Fix
• Feature

What and why

After a rebuild on the engine pin of #444, which includes upstream 7c23cc0 (backslashes separate path components), The Legend of Zelda: Link's Awakening (01006BB00C6F0000) showed every file of its file select as "New game". The save was not lost. Builds before 7c23cc0 took the backslash in save:\savedata0.bin as part of the name, so the save folder (~/Library/Application Support/nxnative/<title ID>/save) holds files named \savedata0.bin, \savedata3.bin, \screenshot0.bin and \screenshot3.bin. The new host looks for savedata0.bin and finds nothing. Mario Kart 8, Wonder, Galaxy 2, DKC Tropical Freeze and Mario vs. DK had no such names on the Mac where it was found. Any game that writes save:\... paths is affected the same way.

Patch 0056 (fs: saves named before backslash paths are copied to their new names at mount) copies each such entry to the name it has now when the save is mounted:

• in the transaction's work folder (save.work), so the copy reaches save only with the game's own Commit, and a kill before that leaves the committed save as it was
• never over an existing file, and the old entry stays (an older build still reads it)
• once: the old entry gets the attribute org.d2rmobile.backslash-copied, so a file the game erases later stays erased
• one log line per copy: save: \savedata0.bin copied to savedata0.bin (...)

The Mac and the iOS app both mount saves through hle_fs.c (DM_SAVE), so both are covered. The device save (<DM_SAVE>_device) is covered too. The reference entry is "Saves named by a build before backslash paths" in docs/reference/services.md, with the one limit it has (cloud saves do not carry the mark).

The patch says Upstream-Status: pending: this PR does not send the change to seedds/nxnative, a maintainer can forward it. The Issue: line names this PR. The number 0056 is free on main today.

Checked

• Tests: make -C engine/dm/host/tests GAME=01006BB00C6F0000 run (all host tests, including the new t_fs_backslash, 26 checks), make ... asan (ASan and UBSan, all host tests), python3 -m unittest dm.tools.tests.test_docs in engine/, python3 tools/engine.py check (35 patches apply to cd859c3). The same commit, cherry-picked onto seedds/nxnative main, passes t_fs_backslash, t_fs, t_fs_case and the doc tests there.
• Run on a Mac: Link's Awakening (01006BB00C6F0000, update v131072) built with --platform mac from this engine (shader chain b7cd656abd7c), Apple silicon, macOS 26. The save folder held only \savedata0.bin, \savedata3.bin, \screenshot0.bin and \screenshot3.bin from a build before 7c23cc0. The log shows the four copies at mount and no red line. The file select shows File 1 (Dampé's Hut, 27-10-2026 21:43) and the autosave (Tal Tal Heights, 21:41) instead of "New game". After the game's Commit the committed save holds both names, the copies are byte for byte the old files, and the old entries carry the mark.
• Not checked: clang-tidy (no LLVM clang-tidy on this Mac, CI runs it upstream), an iPhone run.

Screenshots

None, no visible change.

Scope

• No engine file (dm/, scripts/, docs/, ref/) is added to the repository: a change there is a patch in patches/ (a commit in engine/, then tools/engine.py export, and tools/engine.py check passes), with its Upstream-Status
• A fix to the engine or a game profile also goes to seedds/nxnative as a PR in parallel: this PR's patch says forwarded seedds/nxnative#..., or pending until that PR is open (not sent from here: the patch says pending, a maintainer can forward it)
• A change to a launcher view has before and after screenshots above (this PR changes no launcher view)
• No keys, game files or data extracted from a game in the change or the attachments

🤖 Generated with Claude Code

[v0lumehi]

Thanks for the fix and for the careful write-up, @JoseZamoraCifras. I read the patch and ran the tests. The copy is safe: it works in the work folder, never overwrites a file and keeps the old entry. I found no case that loses or damages a save.

Some points for the docs and the patch:

• If both \dir and dir exist, the old folder is not merged. The files stay, but the game cannot see them.
• A name that leads above the root logs a red line at every mount. It could be marked as done after the first time.
• Without APFS or free space no copy happens, and the save mounts read-only for that session. A line in the reference entry would help.

The number 0056 is free on main today, but #438, #440 and #372 also carry a 0056. Whoever merges second renumbers, so nothing for you to do.

Two questions:

• Do you want to open the pull request to seedds/nxnative yourself? It is your code. If not, I send it and name you as the author. I opened Changes in main that downstream projects need to know about: how do they find out? seedds/nxnative#905 for the question behind it, so the patch can point to that issue.
• The Issue: line names this PR. You could change it to the seedds issue once you agree.