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Merged
EdwardCooke merged 3 commits into from
Apr 9, 2026
Merged

Reduce code duplication in converters and event emitters #1090

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cacbb3f
Extract ScalarConverterBase<T> for DateTime/TimeOnly converter family
fdcastel Mar 26, 2026
1240213
Align event emitter scalar rendering for consistency
fdcastel Mar 26, 2026
07c17d4
Fix JsonEventEmitter NaN/Infinity rendering for JSON compatibility
fdcastel Mar 26, 2026
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22 changes: 6 additions & 16 deletions YamlDotNet/Serialization/Converters/DateOnlyConverter.cs
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Expand Up @@ -32,7 +32,7 @@ namespace YamlDotNet.Serialization.Converters
/// <summary>
/// This represents the YAML converter entity for <see cref="DateOnly"/>.
/// </summary>
public class DateOnlyConverter : IYamlTypeConverter
public class DateOnlyConverter : ScalarConverterBase<DateOnly>
{
private readonly IFormatProvider provider;
private readonly bool doubleQuotes;
Expand All @@ -52,16 +52,6 @@ public DateOnlyConverter(IFormatProvider? provider = null, bool doubleQuotes = f
this.formats = formats.DefaultIfEmpty("d").ToArray();
}

/// <summary>
/// Gets a value indicating whether the current converter supports converting the specified type.
/// </summary>
/// <param name="type"><see cref="Type"/> to check.</param>
/// <returns>Returns <c>True</c>, if the current converter supports; otherwise returns <c>False</c>.</returns>
public bool Accepts(Type type)
{
return type == typeof(DateOnly);
}

/// <summary>
/// Reads an object's state from a YAML parser.
/// </summary>
Expand All @@ -70,9 +60,9 @@ public bool Accepts(Type type)
/// <param name="rootDeserializer">The deserializer to use to deserialize complex types.</param>
/// <returns>Returns the <see cref="DateOnly"/> instance converted.</returns>
/// <remarks>On deserializing, all formats in the list are used for conversion.</remarks>
public object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer)
public override object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer)
{
var value = parser.Consume<Scalar>().Value;
var value = ConsumeScalarValue(parser);

var dateOnly = DateOnly.ParseExact(value, this.formats, this.provider);
return dateOnly;
Expand All @@ -86,12 +76,12 @@ public object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeseria
/// <param name="type"><see cref="Type"/> to convert.</param>
/// <param name="serializer">The root serializer that can be used to serialize complex types.</param>
/// <remarks>On serializing, the first format in the list is used.</remarks>
public void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer)
public override void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer)
{
var dateOnly = (DateOnly)value!;
var formatted = dateOnly.ToString(this.formats.First(), this.provider); // Always take the first format of the list.
var formatted = dateOnly.ToString(this.formats.First(), this.provider);

emitter.Emit(new Scalar(AnchorName.Empty, TagName.Empty, formatted, doubleQuotes ? ScalarStyle.DoubleQuoted : ScalarStyle.Any, true, false));
EmitScalar(emitter, formatted, doubleQuotes ? ScalarStyle.DoubleQuoted : ScalarStyle.Any);
}
}
}
Expand Down
20 changes: 5 additions & 15 deletions YamlDotNet/Serialization/Converters/DateTime8601Converter.cs
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Expand Up @@ -29,7 +29,7 @@ namespace YamlDotNet.Serialization.Converters
/// <summary>
/// This represents the YAML converter entity for <see cref="DateTime"/> using the ISO-8601 standard format.
/// </summary>
public class DateTime8601Converter : IYamlTypeConverter
public class DateTime8601Converter : ScalarConverterBase<DateTime>
{
private readonly ScalarStyle scalarStyle;

Expand All @@ -49,16 +49,6 @@ public DateTime8601Converter(ScalarStyle scalarStyle)
this.scalarStyle = scalarStyle;
}

/// <summary>
/// Gets a value indicating whether the current converter supports converting the specified type.
/// </summary>
/// <param name="type"><see cref="Type"/> to check.</param>
/// <returns>Returns <c>True</c>, if the current converter supports; otherwise returns <c>False</c>.</returns>
public bool Accepts(Type type)
{
return type == typeof(DateTime);
}

/// <summary>
/// Reads an object's state from a YAML parser.
/// </summary>
Expand All @@ -67,9 +57,9 @@ public bool Accepts(Type type)
/// <param name="rootDeserializer">The deserializer to use to deserialize complex types.</param>
/// <returns>Returns the <see cref="DateTime"/> instance converted.</returns>
/// <remarks>On deserializing, all formats in the list are used for conversion.</remarks>
public object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer)
public override object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer)
{
var value = parser.Consume<Scalar>().Value;
var value = ConsumeScalarValue(parser);
var result = DateTime.ParseExact(value, "O", CultureInfo.InvariantCulture, DateTimeStyles.RoundtripKind);

return result;
Expand All @@ -83,11 +73,11 @@ public object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeseria
/// <param name="type"><see cref="Type"/> to convert.</param>
/// <param name="serializer">A serializer to serializer complext objects.</param>
/// <remarks>On serializing, the first format in the list is used.</remarks>
public void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer)
public override void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer)
{
var formatted = ((DateTime)value!).ToString("O", CultureInfo.InvariantCulture);

emitter.Emit(new Scalar(AnchorName.Empty, TagName.Empty, formatted, scalarStyle, true, false));
EmitScalar(emitter, formatted, scalarStyle);
}
}
}
22 changes: 6 additions & 16 deletions YamlDotNet/Serialization/Converters/DateTimeConverter.cs
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Expand Up @@ -31,7 +31,7 @@ namespace YamlDotNet.Serialization.Converters
/// <summary>
/// This represents the YAML converter entity for <see cref="DateTime"/>.
/// </summary>
public class DateTimeConverter : IYamlTypeConverter
public class DateTimeConverter : ScalarConverterBase<DateTime>
{
private readonly DateTimeKind kind;
private readonly IFormatProvider provider;
Expand All @@ -54,16 +54,6 @@ public DateTimeConverter(DateTimeKind kind = DateTimeKind.Utc, IFormatProvider?
this.formats = formats.DefaultIfEmpty("G").ToArray();
}

/// <summary>
/// Gets a value indicating whether the current converter supports converting the specified type.
/// </summary>
/// <param name="type"><see cref="Type"/> to check.</param>
/// <returns>Returns <c>True</c>, if the current converter supports; otherwise returns <c>False</c>.</returns>
public bool Accepts(Type type)
{
return type == typeof(DateTime);
}

/// <summary>
/// Reads an object's state from a YAML parser.
/// </summary>
Expand All @@ -72,9 +62,9 @@ public bool Accepts(Type type)
/// <param name="rootDeserializer">The deserializer to use to deserialize complex types.</param>
/// <returns>Returns the <see cref="DateTime"/> instance converted.</returns>
/// <remarks>On deserializing, all formats in the list are used for conversion.</remarks>
public object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer)
public override object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer)
{
var value = parser.Consume<Scalar>().Value;
var value = ConsumeScalarValue(parser);
var style = this.kind == DateTimeKind.Local ? DateTimeStyles.AssumeLocal : DateTimeStyles.AssumeUniversal;

var dt = DateTime.ParseExact(value, this.formats, this.provider, style);
Expand All @@ -90,13 +80,13 @@ public object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeseria
/// <param name="type"><see cref="Type"/> to convert.</param>
/// <param name="serializer">A serializer to serializer complext objects.</param>
/// <remarks>On serializing, the first format in the list is used.</remarks>
public void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer)
public override void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer)
{
var dt = (DateTime)value!;
var adjusted = this.kind == DateTimeKind.Local ? dt.ToLocalTime() : dt.ToUniversalTime();
var formatted = adjusted.ToString(this.formats.First(), this.provider); // Always take the first format of the list.
var formatted = adjusted.ToString(this.formats.First(), this.provider);

emitter.Emit(new Scalar(AnchorName.Empty, TagName.Empty, formatted, doubleQuotes ? ScalarStyle.DoubleQuoted : ScalarStyle.Any, true, false));
EmitScalar(emitter, formatted, doubleQuotes ? ScalarStyle.DoubleQuoted : ScalarStyle.Any);
}

private static DateTime EnsureDateTimeKind(DateTime dt, DateTimeKind kind)
Expand Down
22 changes: 6 additions & 16 deletions YamlDotNet/Serialization/Converters/DateTimeOffsetConverter.cs
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Expand Up @@ -32,7 +32,7 @@ namespace YamlDotNet.Serialization.Converters
/// To use this converter, call WithTypeConverter(new DateTimeOffsetConverter()) on the
/// <seealso cref="DeserializerBuilder"/> or <seealso cref="SerializerBuilder"/>.
/// </summary>
public class DateTimeOffsetConverter : IYamlTypeConverter
public class DateTimeOffsetConverter : ScalarConverterBase<DateTimeOffset>
{
private readonly IFormatProvider provider;
private readonly ScalarStyle style;
Expand All @@ -59,16 +59,6 @@ public DateTimeOffsetConverter(
this.formats = formats.DefaultIfEmpty("O").ToArray();
}

/// <summary>
/// Gets a value indicating whether the current converter supports converting the specified type.
/// </summary>
/// <param name="type"><see cref="Type"/> to check.</param>
/// <returns>Returns <c>True</c>, if the current converter supports; otherwise returns <c>False</c>.</returns>
public bool Accepts(Type type)
{
return type == typeof(DateTimeOffset);
}

/// <summary>
/// Reads an object's state from a YAML parser.
/// </summary>
Expand All @@ -77,9 +67,9 @@ public bool Accepts(Type type)
/// <param name="rootDeserializer">The deserializer to use to deserialize complex types.</param>
/// <returns>Returns the <see cref="DateTime"/> instance converted.</returns>
/// <remarks>On deserializing, all formats in the list are used for conversion.</remarks>
public object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer)
public override object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer)
{
var value = parser.Consume<Scalar>().Value;
var value = ConsumeScalarValue(parser);
var result = DateTimeOffset.ParseExact(value, formats, provider, dateStyle);

return result;
Expand All @@ -93,12 +83,12 @@ public object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeseria
/// <param name="type"><see cref="Type"/> to convert.</param>
/// <param name="serializer">A serializer to serializer complext objects.</param>
/// <remarks>On serializing, the first format in the list is used.</remarks>
public void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer)
public override void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer)
{
var dt = (DateTimeOffset)value!;
var formatted = dt.ToString(formats.First(), this.provider); // Always take the first format of the list.
var formatted = dt.ToString(formats.First(), this.provider);

emitter.Emit(new Scalar(AnchorName.Empty, TagName.Empty, formatted, style, true, false));
EmitScalar(emitter, formatted, style);
}
}
}
63 changes: 63 additions & 0 deletions YamlDotNet/Serialization/Converters/ScalarConverterBase.cs
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@@ -0,0 +1,63 @@
// This file is part of YamlDotNet - A .NET library for YAML.
// Copyright (c) Antoine Aubry and contributors
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
// of the Software, and to permit persons to whom the Software is furnished to do
// so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

using System;
using YamlDotNet.Core;
using YamlDotNet.Core.Events;

namespace YamlDotNet.Serialization.Converters
{
/// <summary>
/// Base class for YAML type converters that handle a single scalar type.
/// Provides common functionality for type acceptance, scalar consumption, and emission.
/// </summary>
/// <typeparam name="T">The type this converter handles.</typeparam>
public abstract class ScalarConverterBase<T> : IYamlTypeConverter
{
/// <inheritdoc/>
public bool Accepts(Type type)
{
return type == typeof(T);
}

/// <inheritdoc/>
public abstract object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer);

/// <inheritdoc/>
public abstract void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer);

/// <summary>
/// Consumes and returns the scalar value from the parser.
/// </summary>
protected static string ConsumeScalarValue(IParser parser)
{
return parser.Consume<Scalar>().Value;
}

/// <summary>
/// Emits a scalar value with the specified style.
/// </summary>
protected static void EmitScalar(IEmitter emitter, string formatted, ScalarStyle style)
{
emitter.Emit(new Scalar(AnchorName.Empty, TagName.Empty, formatted, style, true, false));
}
}
}
22 changes: 6 additions & 16 deletions YamlDotNet/Serialization/Converters/TimeOnlyConverter.cs
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Expand Up @@ -32,7 +32,7 @@ namespace YamlDotNet.Serialization.Converters
/// <summary>
/// This represents the YAML converter entity for <see cref="TimeOnly"/>.
/// </summary>
public class TimeOnlyConverter : IYamlTypeConverter
public class TimeOnlyConverter : ScalarConverterBase<TimeOnly>
{
private readonly IFormatProvider provider;
private readonly bool doubleQuotes;
Expand All @@ -52,16 +52,6 @@ public TimeOnlyConverter(IFormatProvider? provider = null, bool doubleQuotes = f
this.formats = formats.DefaultIfEmpty("T").ToArray();
}

/// <summary>
/// Gets a value indicating whether the current converter supports converting the specified type.
/// </summary>
/// <param name="type"><see cref="Type"/> to check.</param>
/// <returns>Returns <c>True</c>, if the current converter supports; otherwise returns <c>False</c>.</returns>
public bool Accepts(Type type)
{
return type == typeof(TimeOnly);
}

/// <summary>
/// Reads an object's state from a YAML parser.
/// </summary>
Expand All @@ -70,9 +60,9 @@ public bool Accepts(Type type)
/// <param name="rootDeserializer">The deserializer to use to deserialize complex types.</param>
/// <returns>Returns the <see cref="TimeOnly"/> instance converted.</returns>
/// <remarks>On deserializing, all formats in the list are used for conversion.</remarks>
public object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer)
public override object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeserializer)
{
var value = parser.Consume<Scalar>().Value;
var value = ConsumeScalarValue(parser);

var timeOnly = TimeOnly.ParseExact(value, this.formats, this.provider);
return timeOnly;
Expand All @@ -86,12 +76,12 @@ public object ReadYaml(IParser parser, Type type, ObjectDeserializer rootDeseria
/// <param name="type"><see cref="Type"/> to convert.</param>
/// <param name="serializer">A serializer to serializer complext objects.</param>
/// <remarks>On serializing, the first format in the list is used.</remarks>
public void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer)
public override void WriteYaml(IEmitter emitter, object? value, Type type, ObjectSerializer serializer)
{
var timeOnly = (TimeOnly)value!;
var formatted = timeOnly.ToString(this.formats.First(), this.provider); // Always take the first format of the list.
var formatted = timeOnly.ToString(this.formats.First(), this.provider);

emitter.Emit(new Scalar(AnchorName.Empty, TagName.Empty, formatted, doubleQuotes ? ScalarStyle.DoubleQuoted : ScalarStyle.Any, true, false));
EmitScalar(emitter, formatted, doubleQuotes ? ScalarStyle.DoubleQuoted : ScalarStyle.Any);
}
}
}
Expand Down
16 changes: 11 additions & 5 deletions YamlDotNet/Serialization/EventEmitters/JsonEventEmitter.cs
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Expand Up @@ -21,7 +21,6 @@

using System;
using System.Globalization;
using System.Text.RegularExpressions;
using YamlDotNet.Core;
using YamlDotNet.Core.Events;
using YamlDotNet.Serialization.NamingConventions;
Expand Down Expand Up @@ -87,26 +86,33 @@ public override void Emit(ScalarEventInfo eventInfo, IEmitter emitter)

case TypeCode.Single:
var floatValue = (float)value;
eventInfo.RenderedValue = floatValue.ToString("G", CultureInfo.InvariantCulture);
if (float.IsNaN(floatValue) || float.IsInfinity(floatValue))
{
eventInfo.RenderedValue = floatValue.ToString(CultureInfo.InvariantCulture);
eventInfo.Style = ScalarStyle.DoubleQuoted;
}
else
{
eventInfo.RenderedValue = formatter.FormatNumber(floatValue);
}

break;

case TypeCode.Double:
var doubleValue = (double)value;
eventInfo.RenderedValue = doubleValue.ToString("G", CultureInfo.InvariantCulture);
if (double.IsNaN(doubleValue) || double.IsInfinity(doubleValue))
{
eventInfo.RenderedValue = doubleValue.ToString(CultureInfo.InvariantCulture);
eventInfo.Style = ScalarStyle.DoubleQuoted;
}
else
{
eventInfo.RenderedValue = formatter.FormatNumber(doubleValue);
}
break;

case TypeCode.Decimal:
var decimalValue = (decimal)value;
eventInfo.RenderedValue = decimalValue.ToString(CultureInfo.InvariantCulture);
eventInfo.RenderedValue = formatter.FormatNumber(value);
break;

case TypeCode.String:
Expand Down
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