Paket cannot resolve a conflict on Microsoft.AspNet.Razor when using a local package source #1703

Description

When using a local package source, Paket cannot resolve the dependency conflict between RazorEngine and Microsoft.AspNet.Mvc.

This is likely due to a failure to resolve this dependencies section in RazorEngine's nuspec file:

    <dependencies>
      <group targetFramework=".NETFramework4.0">
        <dependency id="Microsoft.AspNet.Razor" version="[2.0.30506.0]" />
      </group>
      <group targetFramework=".NETFramework4.5">
        <dependency id="Microsoft.AspNet.Razor" version="3.0.0" />
      </group>
    </dependencies>

Repro steps

1. Create a paket.dependencies file with the following:

source \\some-server\network-share
framework: net45
nuget Microsoft.AspNet.Mvc
nuget RazorEngine

1. Copy the nupkgs for these dependencies, and their dependency tree, to \some-server\network-share
2. Run paket.exe update

Expected behavior

Paket resolves Microsoft.AspNet.Razor (>= 3.2.3 < 3.3) to Microsoft.AspNet.Razor (3.2.3).

Actual behavior

Paket version 3.0.0.0
Resolving packages for group Main:
 - Microsoft.AspNet.Mvc 5.2.3
 - RazorEngine 3.8.2
 - RazorEngine 3.7.3
Paket failed with:
        There was a version conflict during package resolution.
  Resolved packages:
   - Microsoft.AspNet.Mvc 5.2.3
   - RazorEngine 3.7.3
  Could not resolve package Microsoft.AspNet.Razor:
   - Microsoft.AspNet.Mvc 5.2.3 requested package Microsoft.AspNet.Razor: >= 3.2.3 < 3.3
   - RazorEngine 3.7.3 requested package Microsoft.AspNet.Razor: 2.0.30506

  Please try to relax some conditions.

Known workarounds

One workaround:

• Remove framework: net45 from paket.dependencies.

Another workaround:

• Use the public gallery (https://api.nuget.org/v3/index.json), not a local source.

Another workaround:

• Use Paket 3.x beta with the public gallery source (above) and a cache directive to the local folder,

Related information

• Operating System: Windows 10.0 (build 10240)
• Issue occurs in (at least) Paket 2.60.2.0, 2.66.3.0, and 3.0.0.0 (beta053)
• .NET 4.6.1 installed on the machine, attempting to target .NET 4.5 for the project Paket is being used in.