Source Generator not running when using System.Text.Json.JsonSerializer: Unraveling the Mystery

Are you stuck with the perplexing issue of Source Generators not running when leveraging the mighty System.Text.Json.JsonSerializer in your .NET application? Fear not, dear developer, for we’re about to embark on a thrilling adventure to conquer this enigmatic problem together!

The Scene of the Crime: Understanding Source Generators

In the world of .NET, Source Generators are a powerful tool that allows developers to generate code at compile-time. This magic happens through the analyzers, which inspect your code, identify areas for improvement, and generate new code to enhance performance, readability, or maintainability. It’s like having a superpower at your fingertips!

<csharp>
public static void Generate(
    [NotNull] IncrementalGeneratorInitializationContext context)
{
    // Your generator code goes here
}
</csharp>

The Suspect: System.Text.Json.JsonSerializer

Now, let’s shift our attention to the System.Text.Json.JsonSerializer, a high-performance JSON serializer that’s part of the .NET ecosystem. This serializer is designed to provide a fast and efficient way to serialize and deserialize JSON data. But, as we’ll discover, it can sometimes interfere with our beloved Source Generators.

<csharp>
var jsonSerializer = JsonSerializer.Serialize(myObject);
</csharp>

The Problem: Source Generator Not Running

So, what happens when we try to use System.Text.Json.JsonSerializer in conjunction with Source Generators? You guessed it – the Source Generator simply refuses to run! It’s as if the serializer is casting a spell of invisibility on our generator code.

Why is this Happening?

To comprehend this enigmatic behavior, we need to dive deeper into the internals of the .NET compiler platform. When you use System.Text.Json.JsonSerializer, it employs a technique called “runtime metadata” to access the compiled assembly’s metadata. This metadata is used to serialize and deserialize JSON data.

The catch? The runtime metadata mechanism bypasses the compilation pipeline, which is where our Source Generators reside. As a result, the generator code is never executed, leaving us perplexed and frustrated.

The Solution: Working Around the Limitation

Fear not, dear developer! We have a few clever workarounds to get our Source Generators up and running again:

• Use a Different Serializer

  One approach is to switch to a different serializer that doesn’t rely on runtime metadata, such as the popular Newtonsoft.Json library. This might require some adjustments to your code, but it’s a viable solution.

  <csharp>
  using Newtonsoft.Json;
  
  var jsonSerializer = JsonConvert.SerializeObject(myObject);
  </csharp>
  

• Separate Compilation

  Another technique involves separating the compilation of your generator code from the serialization logic. This can be achieved by creating a separate assembly for the generator code and referencing it in your main project.

  <csharp>
  // In GeneratorAssembly.csproj
  public static void Generate(
      [NotNull] IncrementalGeneratorInitializationContext context)
  {
      // Your generator code goes here
  }
  </csharp>
  
  // In MainProject.csproj
  <csharp>
  using GeneratorAssembly;
  
  // Use the generated code
  </csharp>
  

• Custom Serialization

  If you’re not tied to a specific serializer, you can create a custom serialization mechanism that doesn’t rely on runtime metadata. This might require more effort, but it grants you complete control over the serialization process.

  <csharp>
  public class CustomSerializer
  {
      public string Serialize(object obj)
      {
          // Custom serialization logic goes here
      }
  }
  </csharp>
  

Conclusion: The Mystery Unraveled

And there you have it, dear developer! We’ve demystified the enigmatic issue of Source Generators not running when using System.Text.Json.JsonSerializer. By understanding the underlying mechanisms and employing clever workarounds, you can overcome this limitation and unlock the full potential of Source Generators in your .NET applications.

Takeaway	Description
Source Generators	Powerful tool for generating code at compile-time
System.Text.Json.JsonSerializer	High-performance JSON serializer that bypasses the compilation pipeline
Workarounds	Use a different serializer, separate compilation, or custom serialization

Remember, in the world of .NET development, understanding the intricacies of the compiler platform and its eco-system is key to unlocking the secrets of the universe (or at least, to solving pesky issues like this one)!

1. Microsoft Docs: Source Generators Overview
2. Microsoft Docs: JsonSerializer Class
3. GitHub Issue: Source Generator not running when using JsonSerializer

Happy coding, and may the source be with you!

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