`npm run switch` Command Fails: Unable to Find OneJS Directory Path

[Candlend]

Problem Description

When using npm run switch nodejs (or other backends) to switch PuerTS backends, the script fails to locate the OneJS Unity package path, resulting in the following error:

OneJS.Runtime.csproj file does not exist.
Error: The "path" argument must be of type string. Received null

Steps to Reproduce

1. Install OneJS using Git URL method (in Packages/manifest.json):

   "com.singtaa.onejs": "https://github.com/Singtaa/OneJS.git"

2. Execute in the App directory:

   npm run switch nodejs

3. Observe the error output

Error Message

Local .tgz found: tmp\PuerTS_Nodejs_2.2.2.tgz
Extraction completed.
OneJS.Runtime.csproj file does not exist.
Error: The "path" argument must be of type string. Received null

Problem Analysis

The getOneJSUnityDir() function in node_modules/onejs-core/scripts/switch.cjs has the following issues:

1. Only supports local paths: The script only checks for local paths with file: prefix (line 120), and cannot handle Git URL type package dependencies

2. Fallback is unreliable: When the path cannot be found from manifest.json, the script attempts to find the OneJS.Runtime.csproj file (line 131), but this file does not exist

3. Missing error handling: When getOneJSUnityDir() returns null, the subsequent code directly uses path.join(null, ...) causing a crash (line 68)

Relevant Code Locations

• File: node_modules/onejs-core/scripts/switch.cjs
• Function: getOneJSUnityDir() (lines 100-176)
• Call site: Process() function (line 68)

// Line 68 - Missing null check
const onejsDir = await getOneJSUnityDir()
const a = path.join(onejsDir, 'Puerts/Editor/com.tencent.puerts.core.Editor.asmdef')
// ...

// Lines 115-126 - Only supports file: paths
if (v.startsWith("file:")) {
    oneJSPath = path.resolve(projectDir, v.substring(5))
    return oneJSPath
}
// Git URL is ignored

// Lines 129-172 - Fallback searches for csproj file
const csprojPath = path.join(projectDir, 'OneJS.Runtime.csproj')
if (fs.existsSync(csprojPath)) {
    // ...
} else {
    console.error('OneJS.Runtime.csproj file does not exist.')
    return null  // Returns null but caller doesn't handle it
}

Expected Behavior

The script should be able to:

1. Support Git URL type package dependencies (look for Unity's Library/PackageCache directory)
2. Provide clearer error messages and usage instructions when the path cannot be found
3. Gracefully handle errors when getOneJSUnityDir() returns null, instead of crashing