bug(idaptik-ums): EditorEngine.res is the compiled .mjs output misnamed as the .res source

[hyperpolymath]

Surface

idaptik-ums/src/editor/EditorEngine.res (and its sibling files in the same dir) contain JavaScript syntax with a literal // Generated by ReScript, PLEASE EDIT WITH CARE header — meaning they are the compiled .res.mjs outputs renamed to .res rather than the original ReScript sources.

Evidence — first 20 lines of the file:

// SPDX-License-Identifier: AGPL-3.0-or-later
// Generated by ReScript, PLEASE EDIT WITH CARE
//
// EditorEngine.res.mjs — Pure computation helpers for the IDApTIK UMS editor.
// ...
import * as EditorModel from "./EditorModel.res.mjs";

function toolLabel(tool) {
  if (typeof tool === "string") {
    switch (tool) {
      case "Select":
        return "Select";
      ...

typeof x === "string", tool.TAG, ES-style import * as — all JavaScript, not ReScript.

Why this matters

When rescript build is run against idaptik-ums/rescript.json (which lists src as a source dir), the compiler fails with:

Syntax error!
  idaptik-ums/src/editor/EditorEngine.res:15:9-11
   15 │ import * as EditorModel from "./EditorModel.res.mjs";
  Did you forget to write an expression here?

…and the build never produces idaptik-ums/src/App.res.mjs. This was masked previously by the soft-fail || echo in the Playwright workflow's sub-build step, then surfaced once PR #114 wired up the sub-build properly. PR #114 has since pivoted to skip the sub-build entirely (vite optimizeDeps.entries scoped to root index.html) because Playwright doesn't actually need idaptik-ums anyway.

Root cause hypothesis

58fe350a (2026-03-22) "feat: AGPL-3.0-or-later license, hub i18n keys, quit fix" or c26463fe (same day) "feat: complete Belt→Core, Js.*→modern, Tauri→Gossamer migration" likely overwrote the original .res source with the compiled .res.mjs content during a global rename pass. Worth checking git show 58fe350a~1:idaptik-ums/src/editor/EditorEngine.res to recover the genuine ReScript source.

Affected files

All .res files in idaptik-ums/src/editor/ and likely idaptik-ums/src/ should be audited for the // Generated by ReScript header. Likely candidates:

• idaptik-ums/src/App.res
• idaptik-ums/src/editor/EditorEngine.res
• idaptik-ums/src/editor/EditorModel.res
• idaptik-ums/src/editor/EditorCanvas.res
• idaptik-ums/src/editor/EditorCmd.res

(any file with // Generated by ReScript in the first 5 lines is impacted)

Fix recipe

For each affected file:

1. Recover the original .res source from before the corrupt-overwrite commit (likely 58fe350a~1 or earlier; bisect to confirm)
2. Restore it as the .res source
3. Re-run cd idaptik-ums && deno run --node-modules-dir=auto --allow-read --allow-write --allow-env --allow-run npm:rescript@12.2.0 and confirm clean build

Once green, PR #114's vite optimizeDeps.entries scoping can be removed (or left as a defensive scope — your call) and the Tauri webview entry will be exercised properly again.

Cross-references

• PR fix(e2e): Playwright fundamental — vite alias + ums sub-build (closes #113) #114 (Playwright fundamental fix) — surfaced this issue; pivoted to avoid the sub-build
• Issue Playwright E2E: vite alias + idaptik-ums sub-build fundamental fix #113 (Playwright E2E parent issue) — being closed by fix(e2e): Playwright fundamental — vite alias + ums sub-build (closes #113) #114
• Commit 58fe350a / c26463fe — likely-culprit commits for the corrupt overwrite

Severity

Low blast radius for the SPA (Playwright tests + main game route '/' are unaffected). High blast radius for the Tauri webview shell (the entire UMS editor UI is unbuildable). Filed as a P2 follow-up.

[hyperpolymath]

Scope expansion (subagent sweep 2026-06-01)

Sweep of all .res files under idaptik-ums/src/ confirms: 10 of 11 files corrupted, only App.res clean.

Corrupted (10)

• idaptik-ums/src/editor/Editor.res
• idaptik-ums/src/editor/EditorCanvas.res
• idaptik-ums/src/editor/EditorCanvasPixi.res
• idaptik-ums/src/editor/EditorCmd.res
• idaptik-ums/src/editor/EditorEngine.res
• idaptik-ums/src/editor/EditorLevelCmd.res
• idaptik-ums/src/editor/EditorModel.res
• idaptik-ums/src/editor/EditorProperties.res
• idaptik-ums/src/editor/EditorToolbar.res
• idaptik-ums/src/editor/EditorValidation.res

Clean (1)

• idaptik-ums/src/App.res — proper ReScript @val external declarations, no "Generated by ReScript" marker

Additional corruption markers identified

Beyond the // Generated by ReScript header and import * as X from "Y.res.mjs" already documented:

• typeof window !== "undefined" browser detection (JS-only)
• typeof entity.kind === "string" runtime tag dispatch (JS-only, not ReScript pattern matching)
• Direct ES6 imports from npm: import * as React from "react", import { Application, Container, Sprite } from "pixi.js"

ReScript would use @external / %raw / proper variant matching — none of those patterns are present in the corrupted files.

Recommendation

Since the corruption is systematic (10/11 in one directory, same signature), bisect git log --all idaptik-ums/src/editor/ between commits c26463fe and 58fe350a to find the offending commit. If the original .res sources can be recovered from earlier history, restoration is mechanical. If not (lost entirely), the directory needs reconstruction — likely a few days of work to rewrite the 10 editor modules in real ReScript.

Until restoration: the vite optimizeDeps.entries: ['index.html'] scoping in PR #114 keeps the SPA build path away from these files. The Tauri webview (which loads idaptik-ums/index.html and depends on EditorEngine.res.mjs et al being properly built) stays broken until this issue resolves.