Analyzers for Minimal APIs

[DamianEdwards]

This is issue is to track ideas for analyzers for Minimal API scenarios:

Errors:

• Detecting when types that implement IActionResult are returned from route handlers. This will result in serializing the result as JSON which is unintended.

  app.Map("/", () => new JsonResult(new { Hello = "World" }));

• Make StartupAnalysisBuilder-based analyzers work with WebApplicationBuilder #34404
• Detecting when attributes are put on a method called by a lambda instead of the lambda itself #35638

  app.Map("/", () => Hello());
  
  [Authorize]
  void Hello() { }

• Create an analyzer to detect mismatched parameter optionality #34553

[captainsafia]

Tagging #34543 onto this as well.

[davidfowl]

@YairHalberstadt can I tempt you with any of these?

[YairHalberstadt]

Sorry @davidfowl got a large enough backlog of stuff to do I'm not willing to take on something else :-)

[davidfowl]

No problem!

[davidfowl]

@martincostello have you written any analyzers before?

[martincostello]

@davidfowl I haven't, but I'd be willing to give it a try. If there's one you'd consider an "easiest" one as a starting point I can see how I get on.

[captainsafia]

@martincostello #35814 might be a good one to get started with. The analyzer will need to find references to a builder.WebHost or builder.Host object and flag any invocations made on that member.

[martincostello]

@captainsafia Thanks for the pointer. I'll take a look at that one at some point over the next few days and see how I get on.

[rafikiassumani-msft]

Closing this issue. We will use the following issue for tracking analyzers work in NET7: #36637