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1.4 regression: Invalid JSON when serializing unions for some configurations #205
Description
Repro code:
open System.Text.Json.Serialization
type MyEnum =
| A
| B
[<Fact>]
let ``Repro`` () =
let options = JsonSerializerOptions(WriteIndented = true)
options.Converters.Add(JsonFSharpConverter(JsonFSharpOptions.FSharpLuLike()))
let json = JsonSerializer.Serialize({| MyField = A |}, options)
%json
.Should()
.Be(
"""{
"MyField": "A"
}"""
)Expected output (and actual output with 1.3):
{
"MyField": "A"
}Actual output with 1.4 (invalid JSON):
{
"MyField":
"Case": "A"
}
Activity
cmeeren commentedon Jun 13, 2025
Another format that fails in the same way:
This horribly broke our production systems. But I guess that's on us for not testing thoroughly enough.
[-]1.4 regression: Invalid JSON for some configurations[/-][+]1.4 regression: Invalid JSON when serializing unions for some configurations[/+]Tarmil commentedon Jun 13, 2025
Ouch, I'm pretty stunned that this managed to pass through my tests :/