vscode node debugger parses inline sourcemap incorrectly

[t83714]

• VSCode Version: 1.17.0
• OS Version: macOS 10.13

Steps to Reproduce:

1. Create an empty folder
2. Add package.json with the following content:

{
  "name": "vscode-issue",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@std/esm": "^0.11.3"
  },
  "@std/esm": {
    "esm": "all",
    "cjs": true
  }
}

3. Create file index.js with the following content:

import path from "path";

console.log(path.resolve(__dirname, ".."));

4. Configure launch.json as:

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "node",
            "request": "launch",
            "name": "Launch Program",
            "program": "${workspaceRoot}/index.js",
            "runtimeArgs": [
                "-r","@std/esm"
            ]
        }
    ]
}

5. npm install
6. Press F5 to start vscode debugger
7. You will see the following error:

Debugging with inspector protocol because Node.js v8.6.0 was detected.
node --inspect-brk=36570 -r @std/esm index.js 
Debugger listening on ws://127.0.0.1:36570/a572c7ff-3251-4ae3-b74c-5abe01c3b73c
Debugger attached.
SourceMaps.getMapForGeneratedPath: exception while processing path: /Users/user/Development/vscode-issue/index.js, sourcemap: data:application/json;charset=utf-8,%7B%22version%22:3,%22sources%22:%5B%22/Users/user/Development/vscode-issue/index.js%22%5D,%22names%22:%5B%5D,%22mappings%22:%22AAAA;AACA;AACA%22%7D
SyntaxError: Unexpected token � in JSON at position 0
    at JSON.parse (<anonymous>)
    at new SourceMap (/Applications/Visual Studio Code.app/Contents/Resources/app/extensions/ms-vscode.node-debug2/node_modules/vscode-chrome-debug-core/out/src/sourceMaps/sourceMap.js:20:25)
    at sourceMapContentsP.then.contents (/Applications/Visual Studio Code.app/Contents/Resources/app/extensions/ms-vscode.node-debug2/node_modules/vscode-chrome-debug-core/out/src/sourceMaps/sourceMapFactory.js:53:28)
    at <anonymous>

Reproduces without extensions: Yes

It seems vscode debugger always assumes the inline sourcemap data URI is in base64 encoding (even if the ;base64 extension is not included in the data URI scheme).

This will lead to data decoding error.

[jdalton]

Possibly related to these lines

https://github.com/Microsoft/vscode/blob/407ce43a5e0bb079b3d0db802a2f7367c2f97c99/build/lib/util.js#L146-L153

Update:

Looks to be convert-source-map dep; thlorenz/convert-source-map#59.

[roblourens]

I didn't know that was valid. convert-source-map isn't involved at all, as far as I know. I just need to update https://github.com/Microsoft/vscode-chrome-debug-core/blob/master/src/sourceMaps/sourceMap.ts#L81

[jdalton]

Oh, rad! Yep, it's allowed 😋

For more info see:

thlorenz/convert-source-map#59 (comment)
and
thlorenz/convert-source-map#48 (comment)

[ramya-rao-a]

@roblourens Moving to March since you are not here ...

[jpike88]

I'm going INSANE with this one. Any movement?

[roblourens]

Is this format commonly used?

I think the right fix will be to take a dependency on that convert-source-map package.

[jpike88]

Some more side information here:

The issue is the inlined source maps aren't being encoded properly. Here is the issue present in getMapForGeneratedPath, and what I see is that the mapPath has HTML entities used which throws everything off.

Going up the stack trace... It's present in onScriptParsed in chromeDebugAdapter.js...

[jpike88]

Still not sure why this issue popped up... I updated a fair amount of dependencies and this happened. Does this have to do with a recent typescript update? Does anyone know of workarounds to this?

[jpike88]

Ohhh it might have been updating @std/esm! If anyone is having this issue downgrading that will probably help things.

[jpike88]

confirming that downgrading to esm@3.0.18 reversed this issue.

[jpike88]

@jdalton would you happen to know the latest non-breaking version of esm that won't re-trigger this issue?

[roblourens]

The encoding is valid, I just haven't gotten to supporting it since it doesn't seem to be very common.

[jpike88]

The error is really obscure though, it might be worth putting in a note regarding this in the error output.

[jdalton]

@jpike88

The only recent change I've done to source maps is to ensure they use a file url instead of a file path (because on Windows the file path is not a valid url and caused load fails in the Node inspector).

@roblourens

It would be great not to have to base64 encode since that's processing and these source maps are generated at runtime. The encoding is just

"//# sourceMappingURL=data:application/json;charset=utf-8," +
  encodeURI(createSourceMap(filename, content))

so decoding is

decodeURI(sourceMappungURL.slice(36))

Update:

I'll prep a PR to patch getInlineSourceMapContents() with support for utf-8 encoded urls.

[roblourens]

That would be fantastic, thanks.

[roblourens]

@Pokute beat you to it but I'll get this into tomorrow's Insiders build.

[jdalton]

Rock, thank you!

[remcohaszing]

I just ran into this issue using VSCode 1.25.1. Just checking… should this fix have been released yet?

[jpike88]

@remcohaszing its in insiders build, not released to the public yet