Idempotent Project Changes can leave Dependency Node Unresolved

[natidea]

Repro Steps

Create a .NET Standard project and add the following package references:

  <ItemGroup>
    <PackageReference Include="Newtonsoft.Json" Version="10.0.0" />
    <PackageReference Include="StyleCop.Analyzers" Version="1.0.2" />
  </ItemGroup>

Observe that the Newtonsoft.Json reference is flagged with warning NU1603 Package not found, approximate best match was resolved.

Add NoWarn="NU1603" to the StyleCop.Analyzers reference (i.e. to the wrong node)

Expected

No changes to dependencies node.

Actual

StyleCop.Analyzers becomes and remains unresolved, anticipating a new resolved node. This is likely because the change did not trigger a dataflow with a "Difference".

Workaround is to make some other change that triggers a dataflow (e.g. change version to 1.0.1)

[drewnoakes]

Another way to trigger this:

• Add a package reference
• Modify metadata on the package (i.e. set NoWarn to nullable)

[drewnoakes]

#5335 has another simple way to trigger this behaviour.

[drewnoakes]

Another test case for this is moving a dependency (e.g. PackageReference) from the project file to Directory.Build.props.