Reflection regression - Type.GetType does not skip leading .

[AndriySvyryd]

Description

Type.GetType does not find the type when type name starts with . (dot)..

Reproduction Steps

class MyType
{
    static void Main() => Console.WriteLine(Type.GetType(".MyType"));
}

Expected behavior

Type is found

Actual behavior

Type is not found

Regression?

Yes, this used to work on SDK 8.0.100-preview.4.23171.22

Known Workarounds

No response

Configuration

SDK 8.0.100-preview.4.23210.1
macOS-11.6.7
x64

Other information

No response

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Issue Details

---

Description

GetProperty returns null for a static property on a class in the global namespace, only on OSX.

Reproduction Steps

Run the attached repro

Expected behavior

No exceptions thrown

Actual behavior

System.NullReferenceException : Object reference not set to an instance of an object.

Regression?

Yes, this used to work on SDK 8.0.100-preview.4.23171.22

Known Workarounds

No response

Configuration

SDK 8.0.100-preview.4.23210.1
macOS-11.6.7
x64

Other information

No response

Author:	AndriySvyryd
Assignees:	-
Labels:	area-System.Reflection, untriaged
Milestone:	-

[AaronRobinsonMSFT]

/cc @buyaa-n

[jkotas]

@EgorBo This is very recent regression. My guess is that it was introduced by #83911.

public partial class GlobalNamespaceContextModel : RuntimeModel
{
    static GlobalNamespaceContextModel()
    {
        var model = new GlobalNamespaceContextModel();
        ...
        _instance = model;
    }

    private static GlobalNamespaceContextModel _instance;
    public static IModel Instance => _instance; <- This returns null when invoked by reflection.
}

[EgorBo]

hm.. I can't repro no matter what I do - I tried the exact SDK version + played with R2R/TC modes - it still prints "Success!" on run for me

macOS-x64 13.2.1

[EgorBo]

@AndriySvyryd any extra steps I need to do, does it repro via dotnet run or in VSfM?

[EgorBo]

Also tried to run it in a loop (via bash) and with various stress modes - still no luck reproing

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Issue Details

---

Description

GetProperty returns null for a static property on a class in the global namespace, only on OSX.

Reproduction Steps

Run the attached repro

Expected behavior

No exceptions thrown

Actual behavior

System.NullReferenceException : Object reference not set to an instance of an object.

Regression?

Yes, this used to work on SDK 8.0.100-preview.4.23171.22

Known Workarounds

No response

Configuration

SDK 8.0.100-preview.4.23210.1
macOS-11.6.7
x64

Other information

No response

Author:	AndriySvyryd
Assignees:	EgorBo
Labels:	area-CodeGen-coreclr, untriaged
Milestone:	-

[AndriySvyryd]

I have only been able to repro this on Helix machines via dotnet run.

It doesn't repro on macOS-x64 11.7.5

Here's an updated repro that builds the target assembly at runtime.

[AndriySvyryd]

We also set COMPlus_EnableWriteXorExecute=0 before running this (it's a workaround for a different issue we've hit)

[EgorBo]

Thanks! I was able to repro and investigating now

[EgorBo]

Doesn't look to be #83911 as it still reproduces on Main when I disable that phase. Also reproduces in Debug mode + R2R=0 + JitMinOpts=1 so highly unlikely a JIT issue, still looking

[AndriySvyryd]

Updating Microsoft.CodeAnalysis.CSharp from 4.2.0 to 4.5.0 resolves this issue. So, it can be closed as far as we are concerned.

[EgorBo]

I was bisecting it on locally built runtime and the regression or whatever it was is between [20..25] of march, bisecting further

[EgorBo]

so far looks like #83484, I'll check before-after in a moment to make sure

[EgorBo]

Yes, it's #83484 cc @jkotas

Steps for https://github.com/dotnet/runtime/files/11214690/ReflectionOSX.zip

# I was doing this using 8.0.100-preview.4.23210.1 SDK 
dotnet publish -c Release -r osx-x64 

then I was just executing output binary using corerun from Checked folder

~/prj/runtime/artifacts/bin/coreclr/osx.x64.Checked/corerun \
bin/Release/net8.0/osx-x64/publish/ReflectionOSX.dll

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Tagging subscribers to this area: @dotnet/area-system-reflection
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

GetProperty returns null for a static property on a class in the global namespace, only on OSX.

Reproduction Steps

Run the attached repro

Expected behavior

No exceptions thrown

Actual behavior

System.NullReferenceException : Object reference not set to an instance of an object.

Regression?

Yes, this used to work on SDK 8.0.100-preview.4.23171.22

Known Workarounds

No response

Configuration

SDK 8.0.100-preview.4.23210.1
macOS-11.6.7
x64

Other information

No response

Author:	AndriySvyryd
Assignees:	EgorBo
Labels:	area-System.Reflection, os-mac-os-x, area-CodeGen-coreclr, untriaged
Milestone:	-

[jkotas]

@EgorBo Thank you for taking a look!

The problem is in Type.GetType API and it affects all platforms (it is not OSX specific). I have updated the description. assembly.GetType(".GlobalNamespaceContextModel") is the statement in the repro that triggered the issue.

The issue is that Type.GetType implementation had a quirk that made it ignore leading . in the type name. The new managed type name parser is missing this quirk.