Question about VBCSCompiler.dll process lifetime

[am11]

I was doing some investigation of issue discussed in dotnet/sdk#44922 and found the following comment:

msbuild/src/Build/BackEnd/Components/Communications/DetouredNodeLauncher.cs

Lines 131 to 133 in 9c89563

	// If a process exits but its child processes survive, Tracker waits 30 seconds by default to wait for this process to exit.
	// This slows down C++ builds in which mspdbsrv.exe doesn't exit when it's parent exits. Set this time to 0.
	info.NestedProcessTerminationTimeout = TimeSpan.Zero;

but in reality, VBCSCompiler.dll process keeps running after executing dotnet msbuild (or dotnet build), we get:

$ rm -r obj bin # evict cache
$ dotnet build
$ ps -e -o pid,ppid,args | grep -i vbcs | fold -65
71304     1 /Users/am11/.dotnet10/dotnet exec /Users/am11/.dotn
et10/sdk/10.0.100-alpha.1.24567.3/Roslyn/bincore/VBCSCompiler.dll
 -pipename:_UckHksr8RUqDGzqnwgGw7cOMBqfRYBBs8oEnOvtDzY

It does go away on its own after exactly 600 seconds (10 minutes). If this is by design:

1. where is this timeout specified?
2. is there any user-facing configuration to change it (make it zero)?

[KalleOlaviNiemitalo]

Perhaps dotnet build --disable-build-servers; I did not test.

Also, dotnet build-server shutdown --vbcscompiler; but see dotnet/sdk#20183.

The 10-minute timeout seems to be at https://github.com/dotnet/roslyn/blob/9bea39d29a00719039d0d3705a15d384bdc385da/src/Compilers/Server/VBCSCompiler/ServerDispatcher.cs#L43-L46. It would be configurable in appsettings https://github.com/dotnet/roslyn/blob/9bea39d29a00719039d0d3705a15d384bdc385da/src/Compilers/Server/VBCSCompiler/BuildServerController.cs#L64 but the configuration is only read on .NET Framework https://github.com/dotnet/roslyn/blob/9bea39d29a00719039d0d3705a15d384bdc385da/src/Compilers/Server/VBCSCompiler/VBCSCompiler.cs#L25-L30.

[am11]

Nice! I knew about build-server shutdown, but --disable-build-servers (or -p:UseSharedCompilation=false) does not spawn it (or shutdown the server after build completion). 👍