Hot reload not triggering when debugging a test

[captainsafia]

Type: Bug

While debugging a test from the Test Explorer, I am not able to apply hot reload after making a change to test code.

I expect that changing some code in the test method and using the hot reload functionality to succesfuly apply the change and restart it.

Logs

C# log

Post the output from Output-->C# here

C# LSP Trace Logs

Post the output from Output-->C# LSP Trace Logs here. Requires the `C#` output window log level to be set to `Trace`

Environment information

VSCode version: 1.98.1
C# Extension: 2.69.22
Using OmniSharp: false

Dotnet Information

.NET SDK: Version: 9.0.200 Commit: 90e8b202f2 Workload version: 9.0.200-manifests.b4a8049f MSBuild version: 17.13.8+cbc39bea8

Runtime Environment:
OS Name: Mac OS X
OS Version: 15.3
OS Platform: Darwin
RID: osx-arm64
Base Path: /Users/captainsafia/git/aspire/child-resources/.dotnet/sdk/9.0.200/

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.2
Architecture: arm64
Commit: 80aa709f5d

.NET SDKs installed:
9.0.200 [/Users/captainsafia/git/aspire/child-resources/.dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 8.0.13 [/Users/captainsafia/git/aspire/child-resources/.dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.2 [/Users/captainsafia/git/aspire/child-resources/.dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 8.0.13 [/Users/captainsafia/git/aspire/child-resources/.dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.2 [/Users/captainsafia/git/aspire/child-resources/.dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
None

Environment variables:
DOTNET_ROOT [/Users/captainsafia/git/aspire/child-resources/.dotnet]

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

Visual Studio Code Extensions

Extension	Author	Version	Folder Name
azure-api-center	apidev	1.0.1	apidev.azure-api-center-1.0.1
azure-dev	ms-azuretools	0.8.4	ms-azuretools.azure-dev-0.8.4
azure-repos	ms-vscode	0.40.0	ms-vscode.azure-repos-0.40.0
catppuccin-vsc	Catppuccin	3.16.1	catppuccin.catppuccin-vsc-3.16.1
code-spell-checker	streetsidesoftware	4.0.40	streetsidesoftware.code-spell-checker-4.0.40
codespaces	GitHub	1.17.3	github.codespaces-1.17.3
codetour	vsls-contrib	0.0.59	vsls-contrib.codetour-0.0.59
copilot	GitHub	1.288.0	github.copilot-1.288.0
copilot-chat	GitHub	0.25.1	github.copilot-chat-0.25.1
csdevkit	ms-dotnettools	1.17.48	ms-dotnettools.csdevkit-1.17.48-darwin-arm64
csharp	ms-dotnettools	2.69.22	ms-dotnettools.csharp-2.69.22-darwin-arm64
docs-build	docsmsft	0.4.6	docsmsft.docs-build-0.4.6
EditorConfig	EditorConfig	0.17.2	editorconfig.editorconfig-0.17.2
github-local-actions	SanjulaGanepola	1.2.3	sanjulaganepola.github-local-actions-1.2.3
github-vscode-theme	GitHub	6.3.5	github.github-vscode-theme-6.3.5
indent-one-space	usernamehw	1.0.0	usernamehw.indent-one-space-1.0.0
jupyter-keymap	ms-toolsai	1.1.2	ms-toolsai.jupyter-keymap-1.1.2
jupyter-renderers	ms-toolsai	1.1.0	ms-toolsai.jupyter-renderers-1.1.0
mokka	Demenskiy	2.0.5	demenskiy.mokka-2.0.5
night-owl	sdras	2.1.1	sdras.night-owl-2.1.1
nord-visual-studio-code	arcticicestudio	0.19.0	arcticicestudio.nord-visual-studio-code-0.19.0
powershell	ms-vscode	2025.0.0	ms-vscode.powershell-2025.0.0
remote-containers	ms-vscode-remote	0.401.0	ms-vscode-remote.remote-containers-0.401.0
remote-repositories	ms-vscode	0.42.0	ms-vscode.remote-repositories-0.42.0
remote-wsl	ms-vscode-remote	0.88.5	ms-vscode-remote.remote-wsl-0.88.5
remotehub	GitHub	0.64.0	github.remotehub-0.64.0
rest-client	humao	0.25.1	humao.rest-client-0.25.1
symbols	miguelsolorio	0.0.22	miguelsolorio.symbols-0.0.22
theme-dracula	dracula-theme	2.25.1	dracula-theme.theme-dracula-2.25.1
vscode-azurefunctions	ms-azuretools	1.16.3	ms-azuretools.vscode-azurefunctions-1.16.3
vscode-azureresourcegroups	ms-azuretools	0.10.8	ms-azuretools.vscode-azureresourcegroups-0.10.8
vscode-bicep	ms-azuretools	0.33.93	ms-azuretools.vscode-bicep-0.33.93
vscode-dotnet-runtime	ms-dotnettools	2.2.8	ms-dotnettools.vscode-dotnet-runtime-2.2.8
vscode-github-actions	github	0.27.1	github.vscode-github-actions-0.27.1
vscode-icons	vscode-icons-team	12.11.0	vscode-icons-team.vscode-icons-12.11.0
vscode-jupyter-cell-tags	ms-toolsai	0.1.9	ms-toolsai.vscode-jupyter-cell-tags-0.1.9
vscode-jupyter-slideshow	ms-toolsai	0.1.6	ms-toolsai.vscode-jupyter-slideshow-0.1.6
vscode-pull-request-github	GitHub	0.106.0	github.vscode-pull-request-github-0.106.0
vscode-xml	redhat	0.28.0	redhat.vscode-xml-0.28.0
vscode-yaml	redhat	1.17.0	redhat.vscode-yaml-1.17.0
vscodeintellicode-csharp	ms-dotnettools	2.2.3	ms-dotnettools.vscodeintellicode-csharp-2.2.3-darwin-arm64
vsliveshare	ms-vsliveshare	1.0.5948	ms-vsliveshare.vsliveshare-1.0.5948
vsliveshare-pack	ms-vsliveshare	0.4.0	ms-vsliveshare.vsliveshare-pack-0.4.0

Extension version: 2.69.22
VS Code version: Code 1.98.1 (2fc07b811f760549dab9be9d2bedd06c51dfcb9a, 2025-03-10T15:38:08.854Z)
OS version: Darwin arm64 24.3.0
Modes:

System Info

Item	Value
CPUs	Apple M2 Max (12 x 2400)
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 webnn: disabled_off
Load (avg)	3, 6, 6
Memory (System)	64.00GB (1.82GB free)
Process Argv	. --crash-reporter-id 564dfdb0-e8e3-47c2-81f4-4214e191431e
Screen Reader	no
VM	0%

A/B Experiments

vsliv368:30146709
vspor879:30202332
vspor708:30202333
vspor363:30204092
pythonvspyt551:31249599
vscod805cf:30301675
binariesv615:30325510
py29gd2263:31024239
14424-chatv5:31260050
vscaat:30438848
c4g48928:30535728
azure-dev_surveyone:30548225
962ge761:30959799
2e7ec940:31000449
pythontbext0:30879054
cppperfnew:31000557
dwnewjupytercf:31046870
nativerepl1:31139838
pythonrstrctxt:31112756
nativeloc1:31192215
iacca1:31171482
5fd0e150:31155592
dwcopilot:31170013
6074i472:31201624
dwoutputs:31242946
customenabled:31248079
hdaa2157:31222309
copilot_t_ci:31222730
f5992895:31259995
jda6j935:31233686
pythoneinst12:31262605
bgtreat:31262795
fh1c7952:31258891
6h6a5794:31261449
563cc122:31253270
31787653:31262186
3e8i5726:31263299
0339e702:31259951

[gregg-miskelly]

This worked for me.

Just to be clear, you have Hot Reload enabled? (it is off by default)

Assuming you have it on, can you go to preferences and increase the verbosity of Csharp->Debug->Hot Reload Verbosity, and then include what you see in the ".NET Host Reload" output window pain when you attempt to apply a change?

[gregg-miskelly]

@captainsafia can you share more repro steps? Or should we just close this?

[captainsafia]

@gregg-miskelly Sorry for the delay here!

Just to be clear, you have Hot Reload enabled? (it is off by default)

Yes, I enabled Hot Reload.

Assuming you have it on, can you go to preferences and increase the verbosity of Csharp->Debug->Hot Reload Verbosity, and then include what you see in the ".NET Host Reload" output window pain when you attempt to apply a change?

I can't recall what change I was originally trying to make when I did this but here's the output I see when I make a change to a string literal inside a test case:

2025-04-01 13:10:33.436 [info]  Starting session.
2025-04-01 13:10:53.373 [info]  💡 Possible code changes were found.
2025-04-01 13:10:56.298 [info]  Checking for code updates...
2025-04-01 13:10:56.429 [error]  /Users/captainsafia/git/aspire/main/tests/Aspire.Hosting.Azure.Tests/Aspire.Hosting.Azure.Tests.csproj (line 1): error ENC1005: The current content of source file '/Users/captainsafia/git/aspire/main/tests/Aspire.Hosting.Azure.Tests/ExistingAzureResourceExtensionsTests.cs' does not match the built source. Any changes made to this file while debugging won't be applied until its content matches the built source.
2025-04-01 13:10:56.437 [info]  Invalid changes were found. Please refer to the Error List window to fix those issues.
2025-04-01 13:10:59.551 [info]  Checking for code updates...
2025-04-01 13:10:59.570 [error]  /Users/captainsafia/git/aspire/main/tests/Aspire.Hosting.Azure.Tests/Aspire.Hosting.Azure.Tests.csproj (line 1): error ENC1005: The current content of source file '/Users/captainsafia/git/aspire/main/tests/Aspire.Hosting.Azure.Tests/ExistingAzureResourceExtensionsTests.cs' does not match the built source. Any changes made to this file while debugging won't be applied until its content matches the built source.
2025-04-01 13:10:59.571 [info]  Invalid changes were found. Please refer to the Error List window to fix those issues.
2025-04-01 13:11:23.806 [info]  Checking for code updates...
2025-04-01 13:11:23.820 [info]  No code changes were found.
2025-04-01 13:11:27.729 [info]  💡 Possible code changes were found.
2025-04-01 13:11:29.284 [info]  Checking for code updates...
2025-04-01 13:11:29.305 [error]  /Users/captainsafia/git/aspire/main/tests/Aspire.Hosting.Azure.Tests/Aspire.Hosting.Azure.Tests.csproj (line 1): error ENC1005: The current content of source file '/Users/captainsafia/git/aspire/main/tests/Aspire.Hosting.Azure.Tests/ExistingAzureResourceExtensionsTests.cs' does not match the built source. Any changes made to this file while debugging won't be applied until its content matches the built source.
2025-04-01 13:11:29.305 [info]  Invalid changes were found. Please refer to the Error List window to fix those issues.

The issue seems to be:

2025-04-01 13:13:01.232 [info] Invalid changes were found. Please refer to the Error List window to fix those issues.

Although, I don't see anything in the error list that would indicate my change is invalid. I assume it means the Problems output?

[gregg-miskelly]

@captainsafia Do you have a repro you can share?

CC @tmat

[captainsafia]

I was seeing this behavior in the Aspire repo although it has already happened to me in ASP.NET Core.

1. Clone the aspire repo via https://github.com/dotnet/aspire.
2. Run ./build.sh in the root.
3. Run ./start-code.sh to launch VS Code.
4. Find a test in the test explorer to debug. For example, SupportsExistingAppConfigurationWithResourceGroup.
5. Set a breakpoint in the test code.
6. When the breakpoint is hit, modify the source in some trivial fashion (e.g. replace a string literal).
7. Hit the hot reload button.