What is the workflow for debugging the language server?

[NullVoxPopuli]

caveat, this is on a branch for this PR: #615, and I'm trying to verify in-repo (in the gjs test-app in test-packages)

For example, I'm getting "server stopped: timed out" issues, and I'd like to debug what's going on, but atm, I feel very clunky when working with language server development with vscode:

• one terminal: run yarn build --watch
• another terminal: manually run yarn extension:package
• in vscode:
  • (initially) uninstall Glint, and install the local *.vsix file
  • restart extension host
  • open the outputs channel
  • select the glint channel
  • restart glint from the commands prompt
  • observe the restart command was sent
  • receive error that glint couldn't start

I've tried adding logs in the constructor of the language server class, but they never print. maybe there is a way to enable verbose logging?

What I'd like to do is use the actual debugger and breakpoints and such.

Is there a better workflow?
To me, it feels like I'm doing something terribly wrong / dark-ages-esque, and there must be a better way!

[NullVoxPopuli]

Found these Glint settings in vscode:

This is an improvement -- it's not exactly what I was looking for, but it allows me to explore more things.

[NullVoxPopuli]

even with these options tho, I can't get any of my own logging to come out of the server 🤔

[NullVoxPopuli]

gonna see if this helps https://code.visualstudio.com/api/get-started/your-first-extension

[dfreeman]

Like we talked about in Discord, there's a launch config in .vscode/launch.json that will allow you to launch the extension in debug mode directly in an "extension development" instance of Code. This lets you skip a bunch of the steps above, like uninstalling/packaging/installing your local development copy.

For the language server itself, though, I tend to debug in the context of a test rather than live, since the live version of the language server runs in a separate process (it is possible to attach a debugger to that, but generally I've found to be more trouble than it's worth).

[NullVoxPopuli]

one thing I noticed as I've been playing around with this is that diagnostics seem to not be coming through, even though they're correctly recreated. 🤔 I've pushed some stuff up to the PR if you want to take a look

[NullVoxPopuli]

funny enough, neovim is providing diagnostics:

so it's probably just that I don't know how to use vscode 😅

this error in the screenshot, text here:

2. Glint encountered an error computing diagnostics for this file. This is likely a bug in Glint; please file an issue, including any code and/or steps to follow to reproduce the error.
   
   Error: Parse Error at /home/nullvoxpopuli/Development/OpenSource/glint/test-packages/ts-template-imports-app/src/index.gts:1:17: 1:29
       at module.exports.__wbg_Error_3c9a6c51df21f7cb (/home/nullvoxpopuli/Development/OpenSource/glint/node_modules/content-tag/content_tag.js:292:17)
       at wasm://wasm/008696fe:wasm-function[371]:0x13efc6
       at wasm://wasm/008696fe:wasm-function[1205]:0x1bb467
       at Preprocessor.parse (/home/nullvoxpopuli/Development/OpenSource/glint/node_modules/content-tag/content_tag.js:267:18)
       at preprocess (/home/nullvoxpopuli/Development/OpenSource/glint/packages/environment-ember-template-imports/-private/environment/preprocess.js:15:23)
       at parseScript (file:///home/nullvoxpopuli/.local/share/nvim/mason/packages/glint/node_modules/@glint/core/lib/transform/template/rewrite-module.js:67:36)
       at calculateCorrelatedSpans (file:///home/nullvoxpopuli/.local/share/nvim/mason/packages/glint/node_modules/@glint/core/lib/transform/template/rewrite-module.js:36:33)
       at rewriteModule (file:///home/nullvoxpopuli/.local/share/nvim/mason/packages/glint/node_modules/@glint/core/lib/transform/template/rewrite-module.js:16:48)
       at TransformManager.getTransformInfo (file:///home/nullvoxpopuli/.local/share/nvim/mason/packages/glint/node_modules/@glint/core/lib/common/transform-manager.js:243:41)
       at TransformManager.readTransformedFile (file:///home/nullvoxpopuli/.local/share/nvim/mason/packages/glint/node_modules/@glint/core/lib/common/transform-manager.js:56:38)

is unexpected --- I was hoping it would be as nice as the glint cli output:

❯ yarn glint
yarn run v1.22.4
$ /home/nullvoxpopuli/Development/OpenSource/glint/node_modules/.bin/glint
src/index.gts:1:30 - error TS0: Expected ',', got 'string literal (./Greeting, './Greeting')'
   ╭─[/home/nullvoxpopuli/Development/OpenSource/glint/test-packages/ts-template-imports-app/src/index.gts:1:1]
 1 │ import Greeting './Greeting';
   ·                 ────────────
   ╰────

1 import Greeting './Greeting';
                               
2 
  

though, there is a but of duplication here -- been trying some message formatting from swc

[dfreeman]

I don't have the time to try and debug your PR for you, but I can say from looking over the diff that console.log calls in the language server are a recipe for a bad time: Code uses stdout for IPC with language servers, so emitting arbitrary text there will usually make it throw up its figurative hands and assume the server is broken.

[NullVoxPopuli]

Thats very helpful information! Thank you!

[lifeart]

@NullVoxPopuli diagnostics issue may be related to #407