Blazor app - 8.0.1 AOT producing Json errors

[Sean4572435243]

Description

I get this error underneath my function call

FAILURE: System.NotSupportedException: ConstructorContainsNullParameterNames, System.Collections.Generic.KeyValuePair2[System.String,System.Collections.Generic.List1[System.String]] at System.Text.Json.Serialization.Metadata.DefaultJsonTypeInfoResolver.GetTypeInfo(Type , JsonSerializerOptions ) at System.Text.Json.JsonSerializerOptions.CachingContext.CreateCacheEntry(Type type, CachingContext context) --- End of stack trace from previous location --- at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& , Thread ) --- End of stack trace from previous location --- at (and then my function stack)

This error does not appear when AOT is disabled, and I'm not using JsonSerializer for anything. In fact, I rolled my own serialization logic because I thought it was something related to the .net serializer.

What's really interesting, is if I just eat this error and continue, it doesn't happen again, so I'm purposely inciting and eating this error in my initialization now.

Reproduction Steps

Will be very time-consuming to reduce my project to a working sample. Let's pursue that if what I've provided isn't enough.

Expected behavior

no errors

Actual behavior

the indicated error

Regression?

There's nothing wrong with my code. It works perfectly when AOT is disabled. AOT breaks it.

Known Workarounds

Eat the initial errors, works great after that

Configuration

latest everything

Other information

No response

[ghost]

Tagging subscribers to this area: @dotnet/area-system-text-json, @gregsdennis
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

I get this error underneath my function call

FAILURE: System.NotSupportedException: ConstructorContainsNullParameterNames, System.Collections.Generic.KeyValuePair2[System.String,System.Collections.Generic.List1[System.String]] at System.Text.Json.Serialization.Metadata.DefaultJsonTypeInfoResolver.GetTypeInfo(Type , JsonSerializerOptions ) at System.Text.Json.JsonSerializerOptions.CachingContext.CreateCacheEntry(Type type, CachingContext context) --- End of stack trace from previous location --- at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& , Thread ) --- End of stack trace from previous location --- at (and then my function stack)

This error does not appear when AOT is disabled, and I'm not using JsonSerializer for anything. In fact, I rolled my own serialization logic because I thought it was something related to the .net serializer.

What's really interesting, is if I just eat this error and continue, it doesn't happen again, so I'm purposely inciting and eating this error in my initialization now.

Reproduction Steps

Will be very time-consuming to reduce my project to a working sample. Let's pursue that if what I've provided isn't enough.

Expected behavior

no errors

Actual behavior

the indicated error

Regression?

There's nothing wrong with my code. It works perfectly when AOT is disabled. AOT breaks it.

Known Workarounds

Eat the initial errors, works great after that

Configuration

latest everything

Other information

No response

Author:	Sean4572435243
Assignees:	-
Labels:	area-System.Text.Json, untriaged
Milestone:	-

[eiriktsarpalis]

Duplicate of dotnet/aspnetcore#52947

[Sean4572435243]

Not sure if it's the same issue. I agree under the hood, the deprecated serialization of KeyValuePair in 8.0 is the issue, but I'd like to add the following notes because I believe this shouldn't have generated the error in the first place.

I have:

var myBytes = new byte[] {234, 146, 62, 14};

The code:

var bytesSum = myBytes.Sum(b => b);

will trigger the exception indicated, whereas this alternate approach:

var bytesSum = myBytes[0] + myBytes[1] + myBytes[2] + myBytes[3];

works fine.

[Sean4572435243]

And here's another example of strange AOT behavior eliciting this exception, once again by LINQ and 'not' directly using serialization or KeyValuePair. This code triggers the exception:

var myBytes = myInts.SelectMany(BitConverter.GetBytes).ToArray();

But this alternative approach works fine

var myBytes = new byte[myInts.Length * 4];
for (int i = 0; i < myInts.Length; i++)
    Buffer.BlockCopy(BitConverter.GetBytes(myInts[i]), 0, myBytes, i * 4, 4);