MAME Content Fails to Load When Basename Matches Parent Directory Name

Description

I've got arcade ROMs sorted into their own folders and am running them through the regular MAME core. I was having problems getting Frogger to run and didn't understand why. I checked the logs and saw:

[libretro ERROR] Error: unknown option: frogger
[ERROR] [Content]: Failed to load content

I didn't know what to do, so I pressed on until I got to Breakers. I had the same problem. I then realized for both of those games, the ZIP's basename matched the parent directory's name. (frogger.zip was in a folder called Frogger and breakers.zip is in a folder called Breakers.) I appended (Parenthetical Added as RetroArch Workaround) to both folder names, reimported, and both now load fine.

Expected behavior

The games to load.

Actual behavior

The games don't load if the ZIP file's basename matches its parent folder's name.

Steps to reproduce the bug

1. Put a ROM into a folder that has the same name as the game's basename.
2. Import the game via manual import.
3. Try to load the game.

Version/Commit

You can find this information under Information/System Information

• RetroArch: 1.18.0

Environment information

• OS: Arch Linux (KDE Plasma 6.0.4, Wayland session)
• Official AppImage build

Reproduce the failure using manual import with a ZIP whose basename matches its parent directory, as described in the issue. Trace the manual-import and content-loading entry points to identify where the parent directory name is treated as an option; done means both Frogger- and Breakers-like layouts load successfully without renaming their folders.