Description

Calling System.Diagnostics.Debugger.Break() should cause the debugger to stop by triggering a user breakpoint at the location where the function was called.

Reproduction Steps

Call Debugger.Break() in small C# console app

Expected behavior

Debugger should stop as if it hit a breakpoint when Debugger.Break() is called

Actual behavior

A System.Runtime.InteropServices.COMException is triggered

Regression?

This is a regression in .NET 9 main builds

Known Workarounds

N/A

Configuration

All OS's and Architectures

Other information

DebuggerUserBreakpoint::IsFrameInDebuggerNamespace is checking the Namespace and the Class by converting a UTF8 string into a Unicode string:

The MAKE_WIDEPTR_FROMUTF8 macro uses ConvertUtf8_Unicode which was re-written in #96099. The original implementation seemed to accept zero-length strings, but the new one will now throw an exception. I am not sure if ConvertUtf8_Unicode intends to support zero length strings (if yes we should consider updating the function). We can work around this particular issue by avoiding converting zero-length strings in DebuggerUserBreakpoint::IsFrameInDebuggerNamespace.