Sourcemap is likely to be incorrect: a plugin (unplugin-auto-expose-preload) was used to transform files, but didn't generate a sourcemap for the transformation

[cawa-93]

Sourcemap is likely to be incorrect: a plugin (unplugin-auto-expose-preload) was used to transform files, but didn't generate a sourcemap for the transformation

[raphael10-collab]

I also noted that the compilation seem go fine, but the final output does not work :

(base) raphy@pc:~/ViteElectronReactBuilder$ yarn compile
yarn run v1.22.18
$ cross-env MODE=production npm run build && electron-builder build --config .electron-builder.config.js --dir --config.asar=false

> build
> npm run build:main && npm run build:preload && npm run build:renderer


> build:main
> cd ./packages/main && vite build

vite v3.0.0-alpha.11 building SSR bundle for production...
✓ 3 modules transformed.
dist/index.cjs   1.92 KiB
dist/index.cjs.map 9.82 KiB

> build:preload
> cd ./packages/preload && vite build

vite v3.0.0-alpha.11 building SSR bundle for production...
✓ 3 modules transformed.
rendering chunks (1)...Sourcemap is likely to be incorrect: a plugin (unplugin-auto-expose-preload) was used to transform files, but didn't generate a sourcemap for the transformation. Consult the plugin documentation for help
dist/index.cjs   0.44 KiB
dist/index.cjs.map 0.09 KiB

> build:renderer
> cd ./packages/renderer && vite build

vite v3.0.0-alpha.11 building for production...
transforming (7) ../../node_modules/.vite/deps_build/react.js'jsx' is not exported by '../../node_modules/react/jsx-runtime.js'
'jsxs' is not exported by '../../node_modules/react/jsx-runtime.js'
'Fragment' is not exported by '../../node_modules/react/jsx-runtime.js'
✓ 10 modules transformed.
dist/index.html          0.36 KiB
dist/index.46c79699.js   139.70 KiB / gzip: 45.14 KiB
dist/index.46c79699.js.map 419.83 KiB
  • electron-builder  version=23.0.3 os=5.13.0-51-generic
  • loaded configuration  file=/home/raphy/ViteElectronReactBuilder/.electron-builder.config.js
  • writing effective config  file=dist/builder-effective-config.yaml
  • packaging       platform=linux arch=x64 electron=19.0.4 appOutDir=dist/linux-unpacked
  • asar usage is disabled — this is strongly not recommended  solution=enable asar and use asarUnpack to unpack files that must be externally available
  • asar usage is disabled — this is strongly not recommended  solution=enable asar and use asarUnpack to unpack files that must be externally available
Done in 4.80s.


(base) raphy@pc:~/ViteElectronReactBuilder/dist/linux-unpacked$ ls -lah
total 186M
drwxrwxr-x 4 raphy raphy 4.0K Jun 17 12:06 .
drwxrwxr-x 3 raphy raphy 4.0K Jun 17 12:06 ..
-rw-r--r-- 1 raphy raphy 126K Jun 17 12:06 chrome_100_percent.pak
-rw-r--r-- 1 raphy raphy 177K Jun 17 12:06 chrome_200_percent.pak
-rwxr-xr-x 1 raphy raphy 1.1M Jun 17 12:06 chrome_crashpad_handler
-rwxr-xr-x 1 raphy raphy  50K Jun 17 12:06 chrome-sandbox
-rw-r--r-- 1 raphy raphy  10M Jun 17 12:06 icudtl.dat
-rwxr-xr-x 1 raphy raphy 238K Jun 17 12:06 libEGL.so
-rwxr-xr-x 1 raphy raphy 2.9M Jun 17 12:06 libffmpeg.so
-rwxr-xr-x 1 raphy raphy 6.0M Jun 17 12:06 libGLESv2.so
-rwxr-xr-x 1 raphy raphy 4.1M Jun 17 12:06 libvk_swiftshader.so
-rwxr-xr-x 1 raphy raphy 5.6M Jun 17 12:06 libvulkan.so.1
-rw-r--r-- 1 raphy raphy 1.1K Jun 17 12:06 LICENSE.electron.txt
-rw-r--r-- 1 raphy raphy 5.1M Jun 17 12:06 LICENSES.chromium.html
drwxrwxr-x 2 raphy raphy 4.0K Jun 17 12:06 locales
drwxrwxr-x 3 raphy raphy 4.0K Jun 17 12:06 resources
-rw-r--r-- 1 raphy raphy 4.9M Jun 17 12:06 resources.pak
-rw-r--r-- 1 raphy raphy 398K Jun 17 12:06 snapshot_blob.bin
-rw-r--r-- 1 raphy raphy 714K Jun 17 12:06 v8_context_snapshot.bin
-rwxr-xr-x 1 raphy raphy 145M Jun 17 12:06 vite-electron-builder
-rw-r--r-- 1 raphy raphy  107 Jun 17 12:06 vk_swiftshader_icd.json

May be it's related to the Sourcemap issue, or, may be not

[Tanimodori]

Ran into the same problem, the sourcemap seemed incorrect.

[Tanimodori]

After hours of digging out how sourcemap works, here's what I found:

The Plugin

This repository is a bundle of two Rollup plugins: preload (unplugin-auto-expose-preload) and renderer (unplugin-auto-expose-renderer).

The preload plugin calls electron's contextBridge.exposeInMainWorld API to expose exports in preload as __electron_preload__${exp} where exp is the exported name by appending to the end of code.

The renderer plugin scans the preload exports by mlly, and then resolves any import { exp } from '#preload' (that's not configurable currently) by appending export const exp = globalThis.__electron_preload_exp to the end of code.

The Sourcemap

The sourcemap uses Base64 VLQ coding to describe the mappings of source code and the transformed. More info can be found at here and there.

The Problem

According to rollup's API (You can find one with detailed return types here), the return types of load hook (actually transform hook is recommanded to use here btw) used in these plugins are string | null | {code: string, map?: string | SourceMap, ast? : ESTree.Program, moduleSideEffects?: boolean | "no-treeshake" | null, syntheticNamedExports?: boolean | string | null, meta?: {[plugin: string]: any} | null}. Unfortunately these plugins returns string instead of { code: string, map?:string } so the sourcemap WILL be lost here. That's the root of this issue.

The Solution

Other plugins like rollup-plugin-insert uses magic-string for sourcemap manipulating such as appending to the source code, so you needn't calculate the mappings in the complex Base64 VLQ encoding by yourself. So use magic-string to loads the original code, append the exports, generate sourcemap and return it should solve this problem.

[cawa-93]

I am currently very busy volunteering in Ukraine. Not sure when I'll have time to fix it. But pr are welcome