Can debug 2.2 apps, but not 3.0 apps on macOS and (some?) Linux

Environment data

Mac OS (Mojave) dotnet --info output:

.NET Core SDK (reflecting any global.json):
 Version:   3.0.100-preview-009812
 Commit:    e3abf6e935

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  10.14
 OS Platform: Darwin
 RID:         osx.10.14-x64
 Base Path:   /usr/local/share/dotnet/sdk/3.0.100-preview-009812/

Host (useful for support):
  Version: 3.0.0-preview1-27101-02
  Commit:  f1ad6079ca

.NET Core SDKs installed:
  2.1.302 [/usr/local/share/dotnet/sdk]
  2.1.401 [/usr/local/share/dotnet/sdk]
  2.1.500 [/usr/local/share/dotnet/sdk]
  2.2.100-preview1-009349 [/usr/local/share/dotnet/sdk]
  2.2.100-preview2-009404 [/usr/local/share/dotnet/sdk]
  2.2.100-preview3-009430 [/usr/local/share/dotnet/sdk]
  2.2.100 [/usr/local/share/dotnet/sdk]
  3.0.100-preview-009812 [/usr/local/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.6 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.6 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview-18579-0056 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.6 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.0-preview3-27014-02 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview-27122-01 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

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

VS Code version: 1.29.1

C# Extension version: 1.17.1

Steps to reproduce

mkdir consoleapp22
mkdir consoleapp30
cd consoleapp22
dotnet new global

• Edit the global.json file to specify the .NET Core 2.2.100 version.

dotnet new razor
code .

• Open program.cs and put a breakpoint in main.

• Press F5 to launch the debugger

• Click the “yes” button when prompted to add stuff to project

• Select “.NET Core” from the command pallette

• Press F5 to launch the debugger

• Debugger stops at breakpoint

  

• Allow app to exit

• Close VS Code

cd ../consoleapp30
dotnet new razor
code .

• Open program.cs and put a breakpoint in main.
• Press F5 to launch the debugger
• Click the “yes” button when prompted to add stuff to project
• Select “.NET Core” from the command pallette
• Press F5 to launch the debugger

Expected behavior

The debugger stops at the breakpoint in main in program.cs.

Actual behavior

Debugger never stops at breakpoint.

[gregg-miskelly]

I found the problem. With .NET Core 3.0 on OSX, the CoreCLR debugging APIs are behaving in a way that they haven’t before, and the VS Debugger isn’t happy with it. I am working with the CoreCLR team to decide if we should fix VS to be tolerant of this behavior, or if this is a CoreCLR bug.

[gregg-miskelly]

Thanks for the report! We will have a look.