Likely a memory leak

[scoizzle]

Type: Bug

Issue Description

Have a medium sized solution, only 4 projects with ~60k LoC

Steps to Reproduce

Open project, do some editing, prompt Copilot or opencode a couple of times. Process will quickly grow to ~40 GB of ram usage on my machine, causing memory pressure to spike, causing machine to have system wide hitching (mouse movements can lag for example).

Expected Behavior

Language server doesn't use an excessive amount of ram.

Actual Behavior

Language server uses excessive amount of ram; attempted to run a gcdump and it failed.

Extension version: 2.140.8
VS Code version: Code 1.122.1 (Universal) (8761a5560cfd65fdd19ce7e2bd18dab5c0a4d84e, 2026-05-29T09:25:37+02:00)
OS version: Darwin arm64 25.5.0
Modes:

System Info

Item	Value
CPUs	Apple M3 Pro (12 x 2400)
GPU Status	2d_canvas: enabled GPU0: VENDOR= 0x106b [Google Inc. (Apple)], DEVICE=0x0000 [ANGLE (Apple, ANGLE Metal Renderer: Apple M3 Pro, Version 26.5 (Build 25F71))], DRIVER_VENDOR=Apple, DRIVER_VERSION=26.5 ACTIVE Machine model name: Mac Machine model version: 15.7 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: enabled_on trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	9, 7, 6
Memory (System)	18.00GB (4.65GB free)
Process Argv	--crash-reporter-id b3581fc0-76fa-4ced-999f-6b57036b754f
Screen Reader	no
VM	0%

A/B Experiments

vsliv368:30146709
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
4f60g487:31327383
6abeh943:31336334
envsactivate1:31505457
cloudbuttont:31379625
3efgi100_wstrepl:31403338
839jf696:31457053
ec5jj548:31422691
cp_cls_c_966_ss:31454199
inlinechat_v2_hd992725:31505030
8hhj4413:31478653
ge8j1254_inline_auto_hint_haiku:31490510
38bie571_auto:31478678
cp_cls_t_1081:31454832
conptydll_true:31498968
ia-use-proxy-models-svc:31452481
e9c30283:31461165
test_treatment2:31471001
ts_provider_enabled:31458190
c9b86496:31447327
rl_a_xe_098a3278:31513474
idci7584:31464702
e3e4d672:31494082
ei9d7968:31496641
nes-extended-on:31455476
chat:31457767
8hig5102:31480529
89g7j272:31507493
7e187181:31503455
i2gc6536:31499202
52612955:31516516
githubstableflight:31469463
ghj88844:31499326
ddid_c:31478207
1b2f8594:31509479
getcmakediagnosticsoff:31489825
ja75b849:31515466
7df3h592:31512476
pro_large_t:31499376
cp_cls_t_1082:31516087
logging_enabled_new:31498466
j0d79568:31499440
jb_cp_cls_c_632:31510883
748c7209:31512887
cg448276_tst_on:31514358
32d76977:31512328
ha629193:31508444
539gd155_c:31506875
jh5f2457_c:31515489
api_cot_off:31513532
hgf2d445:31517210
prpt_ctrl:31515848

[dibarbet]

@scoizzle a dump will likely be required to fully diagnose this, so please try to capture one (may need to do it fast enough before it spikes way too high). We do have commands to help collect a dump (Collect C# Logs / Collect C# Dev Kit Logs).

Ideally if you can reproduce with a before/after, you can use the collect command to collect both a trace and before/after dumps, see https://github.com/dotnet/vscode-csharp/blob/release/SUPPORT.md#capturing-activity-trace-logging, but the dump is most important.

One thing you can also try is setting dotnet.server.useServerGC to false - on MacOS serverGC can be less aggressive at reclaiming memory and can cause problems.

[scoizzle]

@dibarbet keep getting a failure to upload to GitHub to send the .zip produced by the Collect C# Dev Kit Logs command; any suggestions?