love.filesystem looks for "mods/" in two places: the save directory, and
-- portable installs only -- the game folder, which CacheFs mounts. So a
player who unzips a mod next to the executable of an ordinary install,
which is where very nearly every other game would want it, gets no error
and no mod. The panel just comes up empty, with nothing on screen to
suggest the files are sitting in the wrong folder twenty centimetres away.
That is a hard failure to self-diagnose, and it is worse behind a
launcher: the install lives somewhere the player never opens, so "the
game's mods folder" is a guess to begin with.
The mods panel now looks in those folders before its first listing and
copies what it finds into the tree the game really reads, reporting what
it took in the notice line. It happens on open rather than behind a
button because the failure being fixed is one where nothing suggests
there is anything to press.
Looking is scoped: CacheFs.withMounted puts the folder on the read path
at its own mount point, runs the scan, and takes it straight back off.
Nothing a stray folder contains can shadow a game file or change what the
running game resolves, which is what makes it safe to point at a folder
whose contents nobody has validated. Adoption skips ids the game can
already see, so it is idempotent and never nags twice, and it leaves the
loose folder alone -- deleting files outside the save directory on the
player's behalf is not this code's call to make.
Which strays are worth taking is pure (LauncherMods.pickStrays), matching
how deriveList and locateRoot are already split out, so the engine tier
covers the rules without needing love. SaveData.gameFolders is the old
detectPortable candidate list lifted out unchanged -- portable mode is
just the case where one of those folders holds the marker.
Claude-Session: https://claude.ai/code/session_01JvEthuoNBPfxpvHUD9Pd4N