System.Configuration.ConfigurationManager cannot read AppSettings when published with publishSingleFile=true

[mshobohm]

Description

System.Configuration.ConfigurationManager cannot read AppSettings when published with publishSingleFile=yes

Configuration

.net 5 preview 8
tried out with windows-x64 and linux-64

Regression?

I couldnt get this bug working in 3.1

Other information

C:\Projekte\AppSetting>dotnet --version
5.0.100-preview.8.20417.9

C:\Projekte\AppSetting>dotnet run
OK

C:\Projekte\AppSetting>dotnet publish -c Release
Microsoft (R)-Build-Engine, Version 16.8.0-preview-20414-02+a55ce4fbb für .NET
Copyright (C) Microsoft Corporation. Alle Rechte vorbehalten.

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AppSetting -> C:\Projekte\AppSetting\bin\Release\net50\win-x64\AppSetting.dll
AppSetting -> C:\Projekte\AppSetting\bin\Release\net50\win-x64\publish\

C:\Projekte\AppSetting>C:\Projekte\AppSetting\bin\Release\net50\win-x64\publish\AppSetting.exe
Not Found
(Expected behavior is the output of "OK" as with dotnet run)

AppSetting.zip

Tagging subscribers to this area: @agocke
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[am11]

@agocke, @safern, this is clearly a 3.1 to 5.0.0 regression. Should it be considered for backporting?

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[safern]

@agocke, @safern, this is clearly a 3.1 to 5.0.0 regression. Should it be considered for backporting?

cc: @ericstj @danmosemsft

[danmoseley]

Can someone investigate and understand the issue?

[am11]

@danmosemsft, done and fixed by #42176.

[ericstj]

So the breaking change was that GetEntryAssembly().ManifestModule.Name was returning the app name for single file in 3.x and starting in 5.0 it returns null. System.Configuration.ConfigurationManager was just one consumer of this. Why not undo the change to runtime that caused the regression?