Source generators guide/help

[Cybrosys]

Hello!

I've written a simple source generator for doing DI service registration by using attributes. I am however having an issue where I can't deploy to iOS (hot reload) unless I add this package reference in my app's csproj file:
<PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.8.0" />

To me that is wrong, but unless I do it I get this error:

2023-11-29 10:30:28.104 Xamarin.PreBuilt.iOS[14916:12722053] Could not resolve assembly Microsoft.CodeAnalysis, Version=4.8.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35. Details: Could not load file or assembly '/var/mobile/Containers/Data/Application/F4524867-5DDC-4964-8BC4-FFF8AEE59532/Documents/StoreApp.content/Microsoft.CodeAnalysis.dll' or one of its dependencies.

I don't have this issue using your source generator nor any other source generator, this is only an issue with my own source generator project that my app is referencing.

I am referencing my SG project like this:
<ProjectReference Include="<path to .csproj>" OutputItemType="Analyzer" />

I am not using the attribute ReferenceOutputAssembly="false" as my SG project has the attributes that my SG is looking for.

I tried creating a separate project that only contained the attributes, however, the source generator stopped working then for some reason.

So yeah, I would really like some guide/help as to how to create a SG for MAUI that works, since the Community Toolkit has one and several others work. Is this perhaps an issue with Hot reload and that my SG projected is referenced instead of having it as a NuGet package?

[pictos]

@Cybrosys can you push your code to github and share the link? That will be easier to find what's going on.

Did you add the PrivateAssets property on your PackageReference? Like here

And I recommend you to try setting the ReferenceOutputAssembly="false" on your app project as well

[Cybrosys]

Of course, here's an app and a source generator showing the usage of the attributes:
https://github.com/Cybrosys/maui-repros/tree/main/MauiAppSourceGenerators

The source generator project has attributes that the app decorates its classes with, so that is why I can't use ReferenceOutputAssembly="false". I tried moving the attributes to a separate project, but then the source generator stopped working for some reason.

I've added a ICounterService to MauiProgram.cs and added the [Transient] attribute on the MainPage and [Transient<ICounterService>] on the CounterService implementation.

The source generator generates an extension method on MauiBuilder (.UseSourceGeneratedServiceRegistration()).

I have no issues running this on an Android emulator, but on iOS HR blows up.

[pictos]

The source generator project has attributes that the app decorates its classes with, so that is why I can't use ReferenceOutputAssembly="false". I tried moving the attributes to a separate project, but then the source generator stopped working for some reason.

I used this approach for SG with attributes and it works. You can see here
#1321

look for src/CommunityToolkit.Maui/CommunityToolkit.Maui.csproj

I'll be able to look your code sometime next week

[Cybrosys]

@pictos thank you.

I looked it over and got it working.

• I moved the attributes into their own separate project.
• I updated the source generator to use const strings for the full names of the attributes instead of using typeof(<Attribute>).FullName.
• I updated the main project to reference both projects:

<ProjectReference Include="..\MauiApp1.DependencyInjection\MauiApp1.DependencyInjection.csproj" />
<ProjectReference Include="..\MauiApp1.DependencyInjection.SourceGenerators\MauiApp1.DependencyInjection.SourceGenerators.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />

I've updated the repro with the changes.

I don't know if how I'm doing things in the source generator is good or not, source generation is something I've just started looking at.

[pictos]

Sadly there's no good docs around SG, make sure you don't break the incremental behavior, if you are using an incremental source generator, if can do that you're more than good to go (:

[IeuanWalker]

@pictos do you mind taken a look at my SG having a similar issue but cant get my head around it. I've looked at your PR and it looks very similar to what im doing.

The SG seamed to work and finding the classes/ attributes it needs but the NameArguemnts is always empty - https://github.com/IeuanWalker/Hangfire.RecurringJob.Generator/blob/21547628cd9f2d84aba82a25bac40700b070201d/Scr/RecuringJobGenerator.cs#L64C27-L64C52

I've posted the issue on StackOverflow but not getting any help yet lol - https://stackoverflow.com/questions/77609821/sourcegenerator-attribute-namedarguements-is-empty

[pictos]

@IeuanWalker in order to extract information passed through ctor, you need to use another approach, as you can see here I used a different approach when the info is passed on ctor and another way for optional properties. You can find all my extension methods here

[CliffAgius]

Closed as Answered