Fix MSB4109 error in 5.0 RC1

[martincostello]

Fix MSB4109 error when the Microsoft.Extensions.ApiDescription.Server NuGet package is installed with ASP.NET 5 RC1.

C:\Users\martin.costello\.nuget\packages\microsoft.extensions.apidescription.server\5.0.0-rc.1.20451.17\build\Microsoft.Extensions.ApiDescription.Server.targets(5,38): error MSB4109: Expected a property at position 61 in condition " '$(TargetFrameworkIdentifier)' == '.NETCoreApp' AND [Project.csproj]
C:\Users\martin.costello\.nuget\packages\microsoft.extensions.apidescription.server\5.0.0-rc.1.20451.17\build\Microsoft.Extensions.ApiDescription.Server.targets(5,38): error MSB4109:       $([MSBuild]::VersionLessThanOrEquals('$(TargetFrameworkVersion)', '2.0') ". Did you forget the closing parenthesis? [Project.csproj]

Appears to have been introduced by #25428.

/cc @dougbu

[dougbu]

Whoopsie 🤦 Many thanks @martincostello❕ I'm going to get this in because (obviously) the CI build doesn't validate this *.targets file

[martincostello]

No problem - I wasn't sure of a test to validate it, but just having the package reference appeared to cause the error. Maybe it can just be referenced inside one of the test projects?

I validated the ) was the right fix by adding it to the targets file in my NuGet package cache and then rebuilding, which resolved it.

For the app where I found the problem I just commented-out the package reference to work around the issue for the time being.

[WhatFreshHellIsThis]

@martincostello I'm trying to migrate a big project to .net5 and this is the first sticking point, unfortunately commenting out the package in the .csproj file has not resolved the issue I still get the error. Is this cached somewhere, how did you work around it?

[martincostello]

The workaround I did to test the fix will only work locally. I worked around the problem for CI by just commenting-out usages of the NuGet package until the fix comes with RC2.