ModelBinding regression in 2.1.3

[Suchiman]

Is this a Bug or Feature request?:

Bug

Steps to reproduce (preferably a link to a GitHub repo with a repro project):

https://github.com/Suchiman/MvcRegression

[ApiController]
[Route("api/[controller]")]
public class TestController : Controller
{
    [HttpPost]
    public void Test(List<TestClass> filters = null)
    {
    }
}

public class TestClass
{
    public string Test { get; set; }
}

1. Set breakpoint in the Test method of the TestController
2. Issue following post request

POST https://localhost:44333/api/Test/ HTTP/1.1
Content-Type: application/json
Accept: application/json
Host: localhost:44333
Content-Length: 37

[{"test":"value1"},{"test":"value2"}]

3. Inspect the filters argument

Description of the problem:

After Upgrading from

<PackageReference Include="Microsoft.AspNetCore" Version="2.1.3" />
<PackageReference Include="Microsoft.AspNetCore.Mvc" Version="2.1.2" />

to

<PackageReference Include="Microsoft.AspNetCore" Version="2.1.4" />
<PackageReference Include="Microsoft.AspNetCore.Mvc" Version="2.1.3" />

filters will be an empty list, while it used to be populated with the two elements that were posted in the previous Version.

[mkArtakMSFT]

Thanks for contacting us, @Suchiman.
This issue has been fixed in 2.1.5 release: #8206

[Suchiman]

@mkArtakMSFT is this really the same issue? The linked issue is about a month old and says the entire 2.1.x line is affected but it worked fine in 2.1.2 (2.1.3), this regression was introduced in 2.1.3 (2.1.4) which was released less than a day ago.

[mkArtakMSFT]

Reopening this as this spun up a discussion on our end too... Will update this soon.

[mkArtakMSFT]

@Suchiman, in the meantime, you can decorate the filters parameter with [FromBody] attribute to get the desired behavior.