[System.Text.Json] Serializer loses precision on ulong #52393
Description
Description
Serializing an ulong to JSON within asp.net core loses precision. Stumbled over this while upgrading an older project from traditional ASPnet to .net core 8.
Reproduction Steps
Using .net 8 and System.Text.Json 8.0.0.
public class Test
{
public ulong Key { get; set; }
}
Exposing data via minimal API
app.MapGet("/api/test", async (HttpContext context) =>
{
return new Test() { Key = 2121241830635120343 };
});
The result in the browser is the following:
{
"Key": 2121241830635120400
}
Expected behavior
{
"Key": 2121241830635120343
}
Actual behavior
{
"Key": 2121241830635120400
}
Regression?
No response
Known Workarounds
For the moment I have written a custom JsonConverter which calls ToString for the ulong myself.
Configuration
.net 8, running x64 (emulated on win dev kit arm64) on Windows 11.
System.Text.Json 8.0.0
Other information
No response
