C# Language server crashes when Claude extentions shows diff-file

[johnsj]

Type: Bug

Issue Description

Claude extention attempts to show a diff-file, awaiting my response. Language server then crashes.

Steps to Reproduce

install Clean .net 10
install vscode
install C# dev kit
install claude code extention

install new blazor server app
ask claude to plan a new page and showing code changes before writing the files.
Claude shows a diff file with no file on the left, and new file to be created on the right.

Expected Behavior

Diff-page is shown, language server continues to function

Actual Behavior

Diff-page is shown, language server crashes

Extension version: 2.130.5
VS Code version: Code 1.114.0 (e7fb5e96c0730b9deb70b33781f98e2f35975036, 2026-04-01T09:27:11Z)
OS version: Windows_NT x64 10.0.26200
Modes:

System Info

Item	Value
CPUs	AMD Ryzen 7 7800X3D 8-Core Processor (16 x 4200)
GPU Status	2d_canvas: enabled GPU0: VENDOR= 0x1002, DEVICE=0x744c [AMD Radeon RX 7900 XTX], DRIVER_VENDOR=AMD, DRIVER_VERSION=32.0.23033.1002 ACTIVE GPU1: VENDOR= 0x1002, DEVICE=0x164e [AMD Radeon(TM) Graphics], DRIVER_VERSION=32.0.21043.5001 GPU2: VENDOR= 0x1414, DEVICE=0x008c [Microsoft Basic Render Driver], DRIVER_VERSION=10.0.26100.8115 Machine model name: Machine model version: 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 trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	63.10GB (47.23GB free)
Process Argv	. --crash-reporter-id 331b33d8-5c38-4edc-8d7a-9ed2ffa9cf59
Screen Reader	no
VM	0%

A/B Experiments

vsliv368cf:30146710
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
4f60g487:31327383
6abeh943:31336334
envsdeactivate2:31464701
cloudbuttont:31379625
aihoversummaries_t:31469308
3efgi100_wstrepl:31403338
56b7f661:31457055
use-responses-api:31390855
je187915:31401257
ec5jj548:31422691
cp_cls_t_966_ss:31454198
4je02754:31466945
find_all_ref_in_bg_t:31469306
c3h7c220:31478652
ge8j1254_inline_auto_hint_haiku:31431912
38bie571_auto:31478678
cp_cls_c_1081:31454833
conptydll_true:31489736
ia-use-proxy-models-svc:31452481
e9c30283:31461165
test_treatment2:31471001
idci7584:31464702
nes-ftch-new:31485413
showingstats:31481873
ei9d7968:31458072
534a6447_copy:31478748
nes-extended-on:31455476
chat:31457767
8hig5102:31480529
gpt53codex_dceg9788:31489271
67jbj424:31486320
t-some:31486549
cpptoolson-v2:31475363
signintitlebar:31487064
db0gd219:31481871
h08i8180_copy:31475368
23c7c724:31488001
po_split_t:31488386
ddid_t:31478206
getcmakediagnosticson:31487007
ja75b849:31488522
f5b8g904_t:31489328

[dibarbet]

Thanks for the report - the crash will be fixed in an upcoming release (see #9130), but the underlying error will remain as the claude code extension is creating invalid URIs. See #9087