Debugger attaching too late - Unable to hit breakpoints in Startup.cs

[TroyWitthoeft]

In some situations, it looks like the VS Code debugger is unable to attach fast enough to hit specific breakpoints. For example, if we create a boilerplate C# httptriggered Azure function and add a startup.cs file those "early" breakpoints in the file are often missed. Example repo - https://github.com/TroyWitthoeft/AzureFunctionsHostStartupBug

Example of missed breakpoint

Above, why didn't we hit the first breakpoint?
Is there anything we can do to correct this? I've had quite a few dev's trying to get started with DI in C# using startup.cs and having this issue.

Note, I am posting here on the suggestion of @WardenGnaw who is assisting me in the csharp extension repo at issue 3644. He mentioned that your team might be able to assist.

Thoughts... Is it possible to change the launch.json file or the ${command:azureFunctions.pickProcess} command to correct for this? Is there someway we can signal to the debugger that we are ready for it to attach?

Environment

VSCode = 1.43.0
Azure Functions Extension = 0.21.0
csharp extension = 1.21.12
azure functions core tools = 3.0.2245

dotnet --info

.NET Core SDK (reflecting any global.json):
 Version:   3.1.102
 Commit:    573d158fea

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.16299
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\3.1.102\

Host (useful for support):
  Version: 3.1.2
  Commit:  916b5cba26

.NET Core SDKs installed:
  3.1.101 [C:\Program Files\dotnet\sdk]
  3.1.102 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]`

[ejizba]

Yeah this is somewhat of a known issue. Similar issues for other languages:

• JavaScript: Debugger attaches too late to JavaScript function with "RunOnStartup" option #1492
• Python: Python timer trigger does not run locally when runonstartup is set to true #1841

We're currently blocked on this: Azure/azure-functions-host#4384

[jsacapdev]

this happens for my consistently

.NET Core SDK (reflecting any global.json):
 Version:   3.1.300
 Commit:    b2475c1295

Runtime Environment:
 OS Name:     ubuntu
 OS Version:  18.04
 OS Platform: Linux
 RID:         ubuntu.18.04-x64
 Base Path:   /usr/share/dotnet/sdk/3.1.300/

Host (useful for support):
  Version: 3.1.4
  Commit:  0090613580

.NET Core SDKs installed:
  3.1.300 [/usr/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.App 3.1.4 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 3.1.4 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

vscode

Version: 1.45.1
Commit: 5763d909d5f12fe19f215cbfdd29a91c0fa9208a
Date: 2020-05-14T08:27:22.494Z
Electron: 7.2.4
Chrome: 78.0.3904.130
Node.js: 12.8.1
V8: 7.8.279.23-electron.0
OS: Linux x64 5.3.0-1022-azure

core tools

3.0.2534

c#

1.22.0

azure functions extension

0.22.1