Fix overwriting of $(FundingPackageId) in targets

The existig Devlooped.Sponsors.targets had a bug in that it used the same property name the analyzer uses, for its temporary projection from @(FundingPackageId). This caused the property to overwritten, which manifested as soon as we bumped ThisAssembly.AssemblyInfo, which imports the buggy targets into the sample analyzer too now.

By using `_FundingPackage` as the property name instead, analyzers leveraging ThisAssembly won't have an issue from now on, and more importantly: we remove the limitation that only non-SLv2 versions of ThisAssembly could be used previously (unless you implemented an unintuitive workaround like we do in this commit in the Analyzer.csproj via the @(FundingPackageId) item, which won't be necessary from now on (as soon as we can bump again ThisAssembly).

Author: kzu

samples/dotnet/Analyzer/Analyzer.csproj

@@ -29,6 +29,8 @@
 
   <ItemGroup>
     <InternalsVisibleTo Include="Tests" />
+    <!-- $(FundingPackageId) will suffice once ThisAssembly bumps to this fixed Devlooped.Sponsors.targets -->
+    <FundingAnalyzerPackageId Include="SponsorableLib" />
   </ItemGroup>
 
   <!-- To support tests, fake an extra sponsorable with the test key -->

samples/dotnet/SponsorLink/buildTransitive/Devlooped.Sponsors.targets

@@ -61,13 +61,13 @@
 
   <Target Name="SL_CollectSponsorableAnalyzer" Inputs="@(FundingPackageId)" Outputs="|%(FundingPackageId.Identity)|">
     <PropertyGroup>
-      <FundingPackageId>%(FundingPackageId.Identity)</FundingPackageId>
+      <_FundingPackageId>%(FundingPackageId.Identity)</_FundingPackageId>
     </PropertyGroup>
     <ItemGroup>
        <!--Used to determine installation time, for example, by looking up the analyzer assembly in additional files with: 
               build_metadata.Analyzer.ItemType = Analyzer
               build_metadata.Analyzer.NuGetPackageId = [PackageId] -->
-      <AdditionalFiles Include="@(Analyzer -> WithMetadataValue('NuGetPackageId', '$(FundingPackageId)'))" />
+      <AdditionalFiles Include="@(Analyzer -> WithMetadataValue('NuGetPackageId', '$(_FundingPackageId)'))" />
     </ItemGroup>
   </Target>
 

samples/dotnet/Tests/AnalyzerTests.cs

@@ -213,7 +213,7 @@ public async Task WhenMultipleAnalyzers_ThenReportsOnce()
             .Where(x => x.Properties.TryGetValue(nameof(SponsorStatus), out var _));
 
         Assert.NotEmpty(diagnostics);
-        Assert.Single(diagnostics.Where(x => x.Properties.TryGetValue(nameof(SponsorStatus), out var value)));
+        Assert.Single(diagnostics, x => x.Properties.TryGetValue(nameof(SponsorStatus), out var value));
     }
 
     [Fact]

samples/dotnet/readme.md

@@ -35,4 +35,19 @@ Including the analyzer and targets in a project involves two steps.
 </Project>
 ```
 
+3. Set the package id(s) that will be checked for funding in the analyzer, such as:
+
+```xml
+  <PropertyGroup>
+    <FundingPackageId>SponsorableLib;SponsorableLib.Core</FundingPackageId>
+  </PropertyGroup>
+```
+
+  The default analyzer will report a diagnostic for sponsorship status only 
+  if the project being compiled as a direct package reference to one of the 
+  specified package ids. 
+
+  This property defaults to `$(PackageId)` if present. Otherwise, it defaults 
+  to `$(FundingProduct)`, which in turn defaults to `$(Product)` if not provided.
+
 As long as NuGetizer is used, the right packaging will be done automatically.