JS error highlighting stops working in some cases

[dbaeumer]

From @nrkn on April 20, 2016 4:46

• VSCode Version: 1.0.0
• OS Version: Windows 10 Pro

I have no extensions installed. node.js v5.10.1

Error highlighting has stopped working in our node.js app - I was able to reduce it to a very minimal test case:

A single index.js containing an erroneous line so you can see if error highlighting is on
A single subfolder containing a package.json with grunt and grunt-browserify packages and a node_modules folder created by running npm install against the package.json
Standard vscode files - .vscode/launch.json and jsconfig.json

Steps to Reproduce:

1. Clone this repo or recreate structure above from this gist
2. Navigate to ./sub and run npm install
3. Open main folder in VSCode
4. View ./index.js - there is no error highlighting

I have reproduced this on 3 machines

Almost any change to this minimum case, like removing the node_modules folder, removing use strict from the index.js etc., removing the vscode files etc. prevents the bug from being triggered, and error highlighting starts working again, however our app is not a minimal test case so knowing that isn't much help to us!

Copied from original issue: microsoft/vscode#5530

[dbaeumer]

From @nrkn on April 20, 2016 5:16

BTW, there are a ton of ways to fix the min case so that it works, like adding node_modules to the exclude in jsconfig.json - but none of these fixes helps in our full app. Am at quite the loss as to how to proceed. Please let me know if I can provide any more info.

Intellisense is also down.

[dbaeumer]

@nrkn thanks a lot for this nice test case. I was able to reproduce this immediately. First analysis shows that the tsserver which is powering JavaScript language smartness throws on reading the project info. We need to do two things here:

• let the user know that reading the project info failed.
• make a issue for the TS team.

[dbaeumer]

Above the request / response trace I get in VSCode

[billti]

@zhengbli can you take a look and see why tsserver is having issues with this repro?

[zhengbli]

This looks like the old issue where when the files in node_modules are included in the project, it takes a very long time to process the project. Because the project is not ready, asking for project info will result in an error. #7486 is likely to fix the issue once it goes in. By default, the node_modules in the project root level will be excluded, however in his case the folder is inside a child folder sub, therefore its content is included. In fact, if waiting long enough, the error marks will show up eventually, it's just really slow right now.

Work around: edit the jsconfig.json so it looks like:

{
  "compilerOptions": {
    "target": "es6",
    "module": "commonjs"
  },
  "exclude": [
    "sub/node_modules"
  ]
}

[nrkn]

Brilliant. Though I'd already tried using exclude in our main app (not the minimal test) with no luck, I'd only been excluding a couple of things (including sub-folders' node_modules) and it is quite a large project.

By knowing that this was the cause I was able to get error highlighting and intellisense back by aggressively adding more and more things to the exclude until they started working.

Looking forward to being able to remove some of those things when this fix surfaces!

[zhengbli]

@nrkn out of curiosity, what are the common folders that you need to exclude manually? Are these your source code files or libraries?