ParameterInfo.ToString() is inconsistent with the .NET Framework behavior

[enyim]

Description

I'm porting large amount of legacy code that relies on string comparison of various objects collected via reflection. (Code should run both on .NET Framework and .NET 8.0+)

Part of this code uses ParameterInfo.ToString() that has different behavior between the frameworks. (Changed in #52804, commit 0377084)

4.8 did not distinguish between null and "" Name, while 6+ does. This in itself would not be a problem, as we are not comparing data between frameworks. However, .NET 8 sometimes returns null, sometimes "" for MethodInfo.ReturnParameter.Name, which, with the new behavior breaks tests.

Yes, one could argue that ToString() output is not something to rely on, but

1. there is already large amount of code out there that do rely on it & I believe backward compatibility is more important
2. ToString() in the Reflection APIs (mostly?) still behave as in .NET Framework

Reproduction Steps

See the attached repro project. Build and run both versions.

ParamInfo.zip

net48:

Name = null => "System.Object "
Name = String.Empty => "System.Object "
Are they equal? True

System.Object EndInvoke(System.IAsyncResult)
  ReturnParameter.ToString() = "System.Object "
  Name = null
System.Object EndInvoke(System.IAsyncResult)
  ReturnParameter.ToString() = "System.Object "
  Name = null

net8.0

Name = null => "System.Object"
Name = String.Empty => "System.Object "
Are they equal? False

System.Object EndInvoke(System.IAsyncResult)
  ReturnParameter.ToString() = "System.Object "
  Name = ""
System.Object EndInvoke(System.IAsyncResult)
  ReturnParameter.ToString() = "System.Object"
  Name = null

Expected behavior

ParameterInfo should not distinguish between null and empty names, as both values mean that it does not have a name.

Actual behavior

Difference in behavior.

Regression?

Changed behavior from .NET Framework 4.8

Does not seem to be documented in https://learn.microsoft.com/en-us/dotnet/core/compatibility/6.0

Known Workarounds

No response

Configuration

No response

Other information

No response

[JuergenAuer]

Hi @enyim

Name = null => "System.Object"
Name = String.Empty => "System.Object "
Are they equal? False

first is "System.Object", second is "System.Object " with a space at the end.

Different strings, not the same.

Your NET.4.8 sample - both with a space. Your NET.8: One with, one without a space.

[enyim]

Hi @enyim

Name = null => "System.Object"
Name = String.Empty => "System.Object "
Are they equal? False

first is "System.Object", second is "System.Object " with a space at the end.

Different strings, not the same.

Your NET.4.8 sample - both with a space. Your NET.8: One with, one without a space.

yes, this is the issue I am reporting.