Dart Analyzer very slow/stuck

[JonasJW]

Dart & Flutter has suddenly become unusable slow in VSCode. Intellisense won't load within 30+ seconds, syntax highlighting won't update, jumping to code definitions loads infinitely, etc.

This seems to be especially the case on bigger projects, on a newly created project it works fine. I tried switching to Android Studio which seems to behave similarly (maybe a little better).

I tried uninstalling all extensions, even completely removing VSCode with any data stored and reinstalling it. As soon as I install the Dart extension, it is unusable. I also tried setting the following settings:

"dart.previewLsp": true,
"dart.useLegacyAnalyzerProtocol": true,
"dart.useLsp": false,
"dart.autoImportCompletions": false,

I'm on macOS 14.4, VSCode Version 1.87.2 (Universal),

In the Activity Monitor, there is the dart:analysis_server.dart.snapshot process running with around 1 GB of used memory. I'm not sure if this is normal.

Here is a screenshot from the Dart Analyzer (which I'm also having trouble opening)

dart info output:

General info

• Dart 3.3.2 (stable) (Tue Mar 19 20:44:48 2024 +0000) on "macos_arm64"
• on macos / Version 14.4 (Build 23E214)

Project info

• sdk constraint: '>=2.17.0 <3.0.0'

Process info

Memory	CPU	Elapsed time	Command line
6 MB	0.0%	11:53	dart devtools --machine --allow-embedding
393 MB	100.6%	11:53	dart language-server --protocol=lsp --client-id=VS-Code --client-version=3.85.20240318
29 MB	0.0%	11:53	flutter_tools.snapshot daemon
35 MB	0.1%	00:23	flutter_tools.snapshot debug_adapter
121 MB	10.8%	00:23	flutter_tools.snapshot run --machine --start-paused -d B95DD896-131D-4163-A83C-1AC8A70E8560 --devtools-server-address http:/ --target /main.dart --web-renderer canvaskit --web-port 5000

Any recommendations on how I could possible fix this would be very welcome!

[keertip]

@DanTup , do you see this? Have there been more reports of this kind?

[keertip]

/ cc @bwilkerson

[DanTup]

I've not seen any other reports like this. 100% CPU certainly does not look healthy if it's persisting for a long period after initial analysis.

@JonasJW a few questions:

• How big is the open workspace (code --status I think should give a summary of the number of each file type)
• Might it contain any symlinks (that could result in analyzing more than just this folder, or even cycles?)
• You noted that this issue started recently - are there any things that you updated around the time it started (VS Code, the VS Code extensions, the Dart/Flutter SDKs)?
• Are you able to get a screenshot of the servers Timing page (the one you gave above was the Completion page) which will include timings for a larger set of requests

[MaximeRougieux]

We were having the same issue and using the custom_lint package (v0.5.7).

Removing it completely seems to have solved the issue for us, are you using it too, and can you try to remove it to confirm it comes from there if you are ?

[keertip]

/cc @scheglov

[JonasJW]

@DanTup Thanks for the response and sorry for the late reply.

code --status output:

Version:          Code 1.87.2 (863d2581ecda6849923a2118d93a088b0745d9d6, 2024-03-08T15:21:31.043Z)
OS Version:       Darwin arm64 23.4.0
CPUs:             Apple M1 Pro (8 x 24)
Memory (System):  16.00GB (0.06GB free)
Load (avg):       5, 5, 6
VM:               0%
Screen Reader:    no
Process Argv:     --crash-reporter-id 0c0cb32f-913b-418e-b987-7370929419d6
GPU Status:       2d_canvas:                              enabled
                  canvas_oop_rasterization:               enabled_on
                  direct_rendering_display_compositor:    disabled_off_ok
                  gpu_compositing:                        enabled
                  multiple_raster_threads:                enabled_on
                  opengl:                                 enabled_on
                  rasterization:                          enabled
                  raw_draw:                               disabled_off_ok
                  skia_graphite:                          disabled_off
                  video_decode:                           enabled
                  video_encode:                           enabled
                  webgl:                                  enabled
                  webgl2:                                 enabled
                  webgpu:                                 enabled

CPU %   Mem MB     PID  Process
    0      115   38907  code main
    7       66   38910     gpu-process
    0       16   38911     utility-network-service
    0       33   38923  shared-process
    0       33   82195  ptyHost
    0        0   83841       /bin/zsh -il
    0        0   90120         bash /usr/local/bin/code --status
    9       66   90129           electron-nodejs (cli.js )
    5      246   83837  window [5] (auto_router.gr.dart — exercisable_flutter)
    0       98   83839  extensionHost [5]
    0       33   83879       electron-nodejs (config.js )
    0        0   83961         /usr/bin/script -t 0 /dev/null /usr/bin/arch -arm64e xcrun xcdevice observe --usb
    0       16   83962           /Applications/Xcode.app/Contents/Developer/usr/bin/xcdevice observe --usb
    0        0   83963         /usr/bin/script -t 0 /dev/null /usr/bin/arch -arm64e xcrun xcdevice observe --wifi
    0       16   83964           /Applications/Xcode.app/Contents/Developer/usr/bin/xcdevice observe --wifi
    0      426   83884       /Users/jonas/Documents/flutter/bin/cache/dart-sdk/bin/dart language-server --protocol=lsp --client-id=VS-Code --client-version=3.85.20240327
    0        0   83886       /Users/jonas/Documents/flutter/bin/cache/dart-sdk/bin/dart devtools --machine --allow-embedding
    0       33   89935       electron-nodejs (config.js )
    0       33   89961         electron-nodejs (config.js )
  170     1081   90000           electron-nodejs (config.js )
    0       33   83840  fileWatcher [5]

Workspace Stats: 
|  Window (auto_router.gr.dart — exercisable_flutter)
|    Folder (exercisable_flutter): more than 20346 files
|      File types: transitive_digest(3856) json(1582) png(1354) flat(1004)
|                  jar(976) xml(843) webp(646) ttf(344) stamp(334)
|                  len(275)
|      Conf files: launch.json(1)
|      Launch Configs: dart(13)

To be honest, I'm not quite sure what you mean by your question about symlinks or how I can find out.

Yes, this issue seems to have started just recently without making any noticeable changes such as updating SDKs, installing extensions, etc.

Here are further screenshots, I hope this is the server timing page you meant.

If you have any recommendations what I can try to fix this issue, I'm happy to try that. As mentioned, I have already tried uninstalling Flutter/Dart, VSCode, etc. at the moment I don't know what else I could try.

[lulupointu]

For us updating custom_lint to 0.6.4 fixed the issue 🎉

[DanTup]

@JonasJW thanks - the page I meant was the one marked "Timing" on the left.

Can you also confirm whether you're using any analyzer plugins? A few comments above suggest custom_lint might have have issues (that may be fixed in 0.6.4).

You should be able to check for symlinks by running find . -type l -ls in your project folder.

[JonasJW]

@DanTup thanks for the clarification!

I don't use custom_linter or any analyzer plugins.

When I run find . -type l -ls I get a long list of I suppose symlinks that probably just belong the the packages I use, for example:

111156169        0 lrwxr-xr-x    1 jonas            staff                  29 Mar  8 17:37 ./build/macos/Build/Products/Debug-platform/exercisable_flutter.app/Contents/Frameworks/FirebaseCore.framework/FirebaseCore -> Versions/Current/FirebaseCore

Is that anything out of the ordinary?

Here the screenshots of the "Timing" page: