[Bug]: Process warming in Rider causing UI latency

[danielskovli]

Description

I'm not sure this actually qualifies as a bug, because it may be related to something external on my specific computer, but I think its worth a discussion here regardless.

Using Rider 2025.3.1 and the CSharpier plugin v10.0.1, I'm experiencing UI slowness whenever I start editing a file in a new project or seemingly in general if I haven't made any edits for a few minutes. The specific solution I'm working on right now, where this issue occurs, is this one. However, I have observed this behavior on my computer for a while now.

My read of the situation is the following:

1. CSharpier receives some sort of tick from Rider, and jumps into "keep the formatting process alive" mode
2. CSharpier needs to run a dotnet tool list command, which sometimes takes a good few seconds to complete
3. I have not had any success fixing this behavior by overriding the executable location or disabling the "server mode", but there may be an element of user error here

Below is an excerpt of the logs that I believe to be relevant:

2026-01-28 12:47:08,568 [3905417]   FINE - #c.i.c.CSharpierLogger - Ensure there is a csharpier process for /Users/danielskovli/Git/altinn/altinn-studio/src/Runtime/workflow-engine/src/WorkflowEngine.Data/Entities/WorkflowEntity.cs
2026-01-28 12:47:08,568 [3905417]   FINE - #c.i.c.CSharpierLogger - Looking for csproj in or above /Users/danielskovli/Git/altinn/altinn-studio/src/Runtime/workflow-engine/src/WorkflowEngine.Data/Entities that references CSharpier.MsBuild
2026-01-28 12:47:08,568 [3905417]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/danielskovli/Git/altinn/altinn-studio/src/Runtime/workflow-engine/src/WorkflowEngine.Data/Entities/*.csproj
2026-01-28 12:47:08,569 [3905418]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/danielskovli/Git/altinn/altinn-studio/src/Runtime/workflow-engine/src/WorkflowEngine.Data/*.csproj
2026-01-28 12:47:08,592 [3905441]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/danielskovli/Git/altinn/altinn-studio/src/Runtime/workflow-engine/src/*.csproj
2026-01-28 12:47:08,593 [3905442]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/danielskovli/Git/altinn/altinn-studio/src/Runtime/workflow-engine/*.csproj
2026-01-28 12:47:08,593 [3905442]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/danielskovli/Git/altinn/altinn-studio/src/Runtime/*.csproj
2026-01-28 12:47:08,593 [3905442]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/danielskovli/Git/altinn/altinn-studio/src/*.csproj
2026-01-28 12:47:08,593 [3905442]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/danielskovli/Git/altinn/altinn-studio/*.csproj
2026-01-28 12:47:08,593 [3905442]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/danielskovli/Git/altinn/*.csproj
2026-01-28 12:47:08,593 [3905442]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/danielskovli/Git/*.csproj
2026-01-28 12:47:08,593 [3905442]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/danielskovli/*.csproj
2026-01-28 12:47:08,593 [3905442]   FINE - #c.i.c.CSharpierLogger - Looking for /Users/*.csproj
2026-01-28 12:47:08,593 [3905442]   FINE - #c.i.c.CSharpierLogger - Looking for //*.csproj
2026-01-28 12:47:08,594 [3905443]   FINE - #c.i.c.CSharpierLogger - Running /usr/local/share/dotnet/dotnet tool list in /Users/danielskovli/Git/altinn/altinn-studio/src/Runtime/workflow-engine/src/WorkflowEngine.Data/Entities
2026-01-28 12:47:12,248 [3909097]   FINE - #c.i.c.CSharpierLogger - Running 'dotnet tool list' to look for version
2026-01-28 12:47:12,248 [3909097]   FINE - #c.i.c.CSharpierLogger - Output was: 
 Package Id      Version      Commands       Manifest                                                                                          
----------------------------------------------------------------------------------------------------------------------------------------------
csharpier       1.2.5        csharpier      /Users/danielskovli/Git/altinn/altinn-studio/src/Runtime/workflow-engine/.config/dotnet-tools.json
dotnet-ef       10.0.2       dotnet-ef      /Users/danielskovli/Git/altinn/altinn-studio/src/Runtime/workflow-engine/.config/dotnet-tools.json
2026-01-28 12:47:12,249 [3909098]   FINE - #c.i.c.CSharpierLogger - Using 1.2.5 as the version number.
2026-01-28 12:47:12,249 [3909098]   FINE - #c.i.c.CSharpierLogger - Running /usr/local/share/dotnet/dotnet --info

Steps to Reproduce

Not sure if reproducible on every system. Seems linked to dotnet tool list performance.

On my machine, this command performs very slowly in a fresh Terminal session, but subsequent calls perform very well. This possibly supports the behavior I'm seeing in Rider.

Expected Behavior

I expected typing to be unhindered by the existence of the CSharpier plugin.

Actual Behavior

Typing, even before hitting save, is negatively affected because the whole UI sporadically freezes for a number of seconds when editing files.

[belav]

Could you try running dotnet tool list csharpier and see if that is also slow in a new terminal? That's a potentially easy fix I can make. I didn't realize when implementing this that you can use the command to look for a specific tool.

Otherwise maybe there is a way for me to move this to a background thread that won't affect the UI. I thought I did something like that - possibly around the right click menu option being available. Perhaps this doesn't benefit from those changes, or I made those changes for VS/VSCode.

The goal with "warming up csharpier" was to make the first format of a file fast, but if that warning up is causing a UI freeze for some users I think it makes more sense to remove that code, and let the first format be slow instead.

[danielskovli]

Thanks for looking into this @belav.

dotnet tool list csharpier doesn't seem to perform noticeably faster for me than dotnet tool list. I'm not completely confident about the mechanics involved here, because it's not strictly correlating to new Terminal sessions either. It just seems to be the dotnet tool command itself, sometimes I hit a hot copy and everything is blazingly fast. Other times I get stuck for a handful of seconds while "something" spins up.

I've never experienced the same delay in other dotnet commands, for instance dotnet build. I guess the listing of tools need to consider a bunch of different locations and files, so its not entirely unexpected that delays can occur.

This could very well be something running poorly on my particular machine though, as I've not heard of similar issues from others in my team. However, we're all on slightly different IDE+plugin preferences, so I haven't chased this very far.