[Repo Assist] fix: JsonValue.WriteTo uses InvariantCulture for decimal numbers#1766
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…rs; avoid indentation string alloc
- Number decimal values are now serialized with CultureInfo.InvariantCulture
to prevent invalid JSON output (e.g. '1,5' instead of '1.5') when
WriteTo is called with a TextWriter configured with a non-English culture.
TextWriter.Write(decimal) uses the writer's FormatProvider by default,
which for StreamWriter and other writers is CultureInfo.CurrentCulture.
- Replace System.String(' ', n) per indentation level with a loop writing
individual space chars to avoid allocating one string per newLine call
during pretty-printing.
- Add three regression tests covering the culture-invariant serialization
and custom indentation behaviour.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
This was referenced Apr 29, 2026
…-28-09f2ea7bfb7db127
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🤖 This is an automated pull request from Repo Assist, an AI assistant for this repository.
Root Cause
JsonValue.WriteToserializedNumber(decimal) values usingw.Write(decimal), which callsConvert.ToString(value, writer.FormatProvider). ForStreamWriterand otherTextWriterinstances,FormatProviderdefaults toCultureInfo.CurrentCulture. In cultures that use,as the decimal separator (e.g.de-DE,fr-FR), this produces invalid JSON like{"price":1,5}instead of{"price":1.5}.Fix
w.Write numberwithw.Write(number.ToString(CultureInfo.InvariantCulture))to guarantee the correct decimal point regardless of thread culture.System.String(' ', indentation + plus) |> w.Writewith a direct loop writing individual space characters, eliminating one string allocation per newline in pretty-print mode.Changes
src/FSharp.Data.Json.Core/JsonValue.fs— two-line fix inWriteTotests/FSharp.Data.Core.Tests/JsonValue.fs— three new regression tests:JsonValue WriteTo serializes decimals using InvariantCulture regardless of thread culture(de-DE)JsonValue ToString serializes decimal array using InvariantCulture(fr-FR)JsonValue WriteTo indentation uses correct number of spacesTest Status
Pre-existing infrastructure warning (OpenTelemetry.Api 1.15.0 vulnerability via NuGet audit) suppressed with
-p:NuGetAudit=false; unrelated to this change, tracked in PR #1762.