InvalidOperationException when using string[] parameters with FromForm attribute

[marcominerva]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I have a Minimal API with the following endpoint:

app.MapPost("/api/documents", ([FromForm] string[] values) =>
{
    return TypedResults.Ok();
});

When I run the project, I get the following exception:

An unhandled exception has occurred while executing the request.
      System.InvalidOperationException: TryParse method found on string with incorrect format. Must be a static method with format
      bool TryParse(string, IFormatProvider, out string)
      bool TryParse(string, out string)
      but found
      static Boolean TryParse(System.ReadOnlySpan`1[System.Char], System.IFormatProvider, System.String ByRef)

If I try with other types, like int[], it works correctly.

Exceptions (if any)

An unhandled exception has occurred while executing the request.
      System.InvalidOperationException: TryParse method found on string with incorrect format. Must be a static method with format
      bool TryParse(string, IFormatProvider, out string)
      bool TryParse(string, out string)
      but found
      static Boolean TryParse(System.ReadOnlySpan`1[System.Char], System.IFormatProvider, System.String ByRef)
         at Microsoft.AspNetCore.Http.ParameterBindingMethodCache.<FindTryParseMethod>g__Finder|18_0(Type type)
         at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
         at Microsoft.AspNetCore.Http.ParameterBindingMethodCache.HasTryParseMethod(Type type)
         at Microsoft.AspNetCore.Http.RequestDelegateFactory.CreateArgument(ParameterInfo parameter, RequestDelegateFactoryContext factoryContext, Boolean& hasTryParse, Boolean& hasBindAsync, Boolean& isAsParameters)
         at Microsoft.AspNetCore.Http.RequestDelegateFactory.CreateArguments(ParameterInfo[] parameters, RequestDelegateFactoryContext factoryContext)
         at Microsoft.AspNetCore.Http.RequestDelegateFactory.CreateArgumentsAndInferMetadata(MethodInfo methodInfo, RequestDelegateFactoryContext factoryContext)
         at Microsoft.AspNetCore.Http.RequestDelegateFactory.InferMetadata(MethodInfo methodInfo, RequestDelegateFactoryOptions options)
         at Microsoft.AspNetCore.Routing.RouteEndpointDataSource.CreateRouteEndpointBuilder(RouteEntry entry, RoutePattern groupPrefix, IReadOnlyList`1 groupConventions, IReadOnlyList`1 groupFinallyConventions)
         at Microsoft.AspNetCore.Routing.RouteEndpointDataSource.get_Endpoints()
         at Microsoft.AspNetCore.Routing.CompositeEndpointDataSource.CreateEndpointsUnsynchronized()
         at Microsoft.AspNetCore.Routing.CompositeEndpointDataSource.EnsureEndpointsInitialized()
         at Microsoft.AspNetCore.Routing.CompositeEndpointDataSource.get_Endpoints()
         at Microsoft.AspNetCore.Routing.DataSourceDependentCache`1.Initialize()
         at System.Threading.LazyInitializer.EnsureInitializedCore[T](T& target, Boolean& initialized, Object& syncLock, Func`1 valueFactory)
         at Microsoft.AspNetCore.Routing.Matching.DataSourceDependentMatcher..ctor(EndpointDataSource dataSource, Lifetime lifetime, Func`1 matcherBuilderFactory)
         at Microsoft.AspNetCore.Routing.Matching.DfaMatcherFactory.CreateMatcher(EndpointDataSource dataSource)
         at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.InitializeCoreAsync()
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.<Invoke>g__AwaitMatcher|10_0(EndpointRoutingMiddleware middleware, HttpContext httpContext, Task`1 matcherTask)
         at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

.NET Version

9.0.301

[captainsafia]

I think this bug is in RDF and is a combination of the interactions between POST metods + [FromForm] attributes + array-based types. Similar issues don't occur when PublishAoT=true and the source generator is at play.

Moving to the backlog for now given prioritization although PRs are welcome. I suspect the bug is related to the logic in thttps://github.com/dotnet/aspnetcore/blob/5d0e0d0dc65d9018faa1d9ce7892e7f4b6238b9d/src/Http/Http.Extensions/src/RequestDelegateFactory.cs#L763.

[dotnet-policy-service]

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