Detect RPG Maker 2000/2003, which was never recognised at all

[rouges78]

Installing an RPG Maker classic to test the complete flow turned up why that flow could never have run.

GameStringer had a branch introducing itself as "RPG Maker classico (RPG_RT 2000/2003)" — with a message for the user and, since #87, the hook into the runtime fallback. That branch was unreachable for exactly those games.

Three layers, blind the same way

Installed Yume Nikki (RPG Maker 2003, free on Steam, app 650700) and queried the commands directly:

detect_rpgmaker_game -> ERRORE: Non sembra essere un gioco RPG Maker

…on a folder holding RPG_RT.exe, RPG_RT.ldb, RPG_RT.lmt, RPG_RT.ini and sixty-odd Map####.lmu.

1. engine_detector::is_rpg_maker() looked for www/data/System.json, Game.rpgproject and rgss*.dll — no check for RPG_RT.*.
2. RpgMakerVersion had no variant for 2000/2003, so detection fell to Unknown and errored.
3. In the frontend that error landed in } catch { /* detect fallito → prosegui col workflow file-based normale */ } — the classic branch was skipped silently.

The fix

A RpgMakerVersion::RT variant, detection on the data files, and a depth-limited search.

For RT, find_data_files returns Ok(vec![]). Zero data files is not an error — it is the fact that routes these games to runtime translation. Returning Err would fail detection and leave the branch as unreachable as before.

Two things worth not relearning

Never look for the executable. Plenty of RPG_RT games rename RPG_RT.exe to the game's title; .ldb and .lmt are never touched. A library scan searching for RPG_RT.exe concludes you own none when you do — which is exactly what my earlier survey did.

The folder depth has to be searched. Steam installs Yume Nikki under common/Yume Nikki/yumenikki/, so looking only in the root misses it — the same trap as Unreal's Paks folders, in a different part of the codebase. detect_rpgmaker_game now reports the folder it found rather than the root, so callers need not repeat the search.

Result

From the install root the app actually passes:

version: RT
path:    …\Yume Nikki\yumenikki      (resolved, not the root)
title:   Yume Nikki
data_files: []          extraction: 0 strings

Precisely the conditions the classic branch tests for (isMvMz false, strings <= 0), so it fires — and with it the runtime fallback from #87.

Verification

Four tests: root detection, subfolder detection, zero-not-error extraction, and a non-RPG-Maker folder. Full Rust suite: 1560 passed, 0 failed. Clippy shows no new warnings (the five in these files are pre-existing acronym and range lints). tauri:check-cmds clean.

probe_rpgmaker is kept as an example so the detector can be queried on any folder without launching the app.

The trap, recorded

A branch with a well-written message, a circumstantial comment and tests downstream looks like live code. This one had been dead from the start — not through a defect of its own, but because of an upstream condition that could never be true. Before believing a path works, exercise it with an input that actually takes it. Here, installing one game was enough.

🤖 Generated with Claude Code