"The package 'NLog' tried to add a framework reference to 'System.IO.Compression' which was not found in the GAC." when the assembly, in fact, is in the GAC

[sandersaares]

NuGet product used: VS UI

NuGet version (x.x.x.xxx): 4.3.0

dotnet.exe --version (if appropriate): N/A

VS version (if appropriate): 15.3.2

OS version (i.e. win10 v1607 (14393.321)): Windows 10 1703 (15063.540)

Worked before? If so, with which NuGet version: unknown

Detailed repro steps so we can see the same problem

1. Create a new .NET Standard 2.0 library project.
2. Add a new .NET Framework 4.7 unit test project.
3. Add a reference the class library.
4. Attempt to install NLog 5.0.0-beta09 into the unit test project.

Attempting to gather dependency information for package 'NLog.5.0.0-beta09' with respect to project 'Tests.NetFramework', targeting '.NETFramework,Version=v4.7'
Gathering dependency information took 662,02 ms
Attempting to resolve dependencies for package 'NLog.5.0.0-beta09' with DependencyBehavior 'Lowest'
Resolving dependency information took 0 ms
Resolving actions to install package 'NLog.5.0.0-beta09'
Resolved actions to install package 'NLog.5.0.0-beta09'
Found package 'NLog 5.0.0-beta09' in 'C:\Source\Toolkit\packages'.
Package 'NLog.5.0.0-beta09' already exists in folder 'C:\Source\Toolkit\packages'
Install failed. Rolling back...
Package 'NLog.5.0.0-beta09' does not exist in project 'Tests.NetFramework'
Executing nuget actions took 1,1 sec
Failed to add reference. The package 'NLog' tried to add a framework reference to 'System.IO.Compression' which was not found in the GAC. This is possibly a bug in the package. Please contact the package owners for assistance.
  Reference unavailable.
Time Elapsed: 00:00:01.7830560
========== Finished ==========

Looking at GAC contents does show me what appears to be System.IO.Compression at c:\Windows\Microsoft.NET\assembly\GAC_MSIL\System.IO.Compression\v4.0_4.0.0.0__b77a5c561934e089\System.IO.Compression.dll. It is not clear to me why NuGet says it cannot be found in the GAC.

The NLog install works fine if you remove the reference to the .NET Standard 2.0 library project.

Installing System.IO.Compression from NuGet seems to slightly move things along but it is not clear why and this should not be needed - System.IO.Compression is already in .NET Framework, there should be no need for any NuGet package here.

See also NLog/NLog#2255

[wburchard]

I've encountered precisely the same problem.

[rohit21agrawal]

@sandersaares @wburchard i am not able to repro this problem at my end using the steps you described. can either of you attach a repro project?

Thanks.

[sandersaares]

Here you go: https://github.com/sandersaares/repro-nuget-5812

Just attempt to install latest prerelease of NLog into the unit test project there (currently 5.0.0-beta11 for me). This will result in Failed to add reference. The package 'NLog' tried to add a framework reference to 'System.IO.Compression' which was not found in the GAC. This is possibly a bug in the package. Please contact the package owners for assistance.

[rohit21agrawal]

@PatoBeltran could you take a look at this and find a repro?