How to get Extension Methods to display when using assembly references

[UmaHarano]

Discussed in #10063

^{Originally posted by UmaHarano July 3, 2024}
I am having issues with extension methods to be listed in the base class.
I have two csproj files in my solution:

• Project A with a "Map" class.
• Project B in the same sln has a "MappingExtensions" class that defines extension methods for the Map class that is defined in Project A.

Issue

• If Project B has a "project reference" to Project A:
  Project A's Map class apiPage yml I generate using DocFX lists the extension methods defined in Project B.
• If Project B has a assembly reference to Project A:
  Project A's Map class apiPage yml I generate using DocFX does not list the extension methods defined in Project B. This is the issue.

The problem is my code base only uses "Assembly reference". So I am missing all the extension methods. Is there a solution or work around you can recommend? I cannot use project references.

[filzrev]

It seems be filtered out by following line.

docfx/src/Docfx.Dotnet/DotnetApiCatalog.ApiPage.cs

Line 439 in d0d5307

.Select(m => m.ReduceExtensionMethod(type))

---

Is there a solution or work around you can recommend? I cannot use project references.

As a temporary workaround.
Is is able to use conditional compilation for docfx metadata command?

docfx.json

"metadata": [
    {
      "properties": {
        "DocfxMetadataBuild": "true"
      }
  ],

ProjectB.csproj

  <ItemGroup Condition="'$(DocfxMetadataBuild)' == 'true'">
    <ProjectReference Include="..\ClassLibrary1\ProjectA.csproj" />
  </ItemGroup>
  
  <ItemGroup Condition="'$(DocfxMetadataBuild)' != 'true'">
    <Reference Include="ProjectA">
      <HintPath>..\ClassLibrary1\bin\Release\net8.0\ProjectA.dll</HintPath>
    </Reference>
  </ItemGroup>

[UmaHarano]

@filzrev
Thanks for the work around. The main reason this won't work is because I am building a documentation site for 17+ dlls. It would be a maintenance issue to evaluate the extensions in them in order to add these compilation conditions.

Any chance this can be fixed in the next round of DocFX updates?

[filzrev]

When using Assembly Reference.
It seems ReduceExtensionMethod returns null at following lines.

docfx/src/Docfx.Dotnet/DotnetApiCatalog.ApiPage.cs

Line 439 in 4d74101

.Select(m => m.ReduceExtensionMethod(type))

Any chance this can be fixed in the next round of DocFX updates?

ReduceExtensionMethod is implemented by Roslyn API.
So It would be difficult to fix on the docfx side.

I've found similar issue at Roslyn repository. But it seems not be resolved.
https://github.com/dotnet/roslyn/issues/11950

[UmaHarano]

Thank you @filzrev for this info.