ThrowHelper.cs

using System.Text.Json;
using System.Reflection;
using System;
using System.Diagnostics;

namespace DarkPatterns.OpenApiCodegen.Json.Extensions;

internal static class ThrowHelper
{
	private static readonly PropertyInfo? s_JsonException_AppendPathInformation
		= typeof(JsonException).GetProperty("AppendPathInformation", BindingFlags.NonPublic | BindingFlags.Instance);

	/// <summary>
	/// Generate a <see cref="JsonException"/> using the internal
	/// <c>JsonException.AppendPathInformation</c> property that will
	/// eventually include the JSON path, line number, and byte position in
	/// line.
	/// <para>
	/// The final message of the exception looks like: The JSON value could
	/// not be converted to {0}. Path: $.{JSONPath} | LineNumber:
	/// {LineNumber} | BytePositionInLine: {BytePositionInLine}.
	/// </para>
	/// </summary>
	/// <param name="propertyType">Property type.</param>
	/// <returns><see cref="JsonException"/>.</returns>
	public static JsonException GenerateJsonException_DeserializeUnableToConvertValue(Type propertyType)
	{
		Debug.Assert(s_JsonException_AppendPathInformation != null);

		JsonException jsonException = new JsonException($"The JSON value could not be converted to {propertyType}.");
		s_JsonException_AppendPathInformation?.SetValue(jsonException, true);
		return jsonException;
	}


	/// <summary>
	/// Generate a <see cref="JsonException"/> using the internal
	/// <c>JsonException.AppendPathInformation</c> property that will
	/// eventually include the JSON path, line number, and byte position in
	/// line.
	/// <para>
	/// The final message of the exception looks like: The JSON value '{1}'
	/// could not be converted to {0}. Path: $.{JSONPath} | LineNumber:
	/// {LineNumber} | BytePositionInLine: {BytePositionInLine}.
	/// </para>
	/// </summary>
	/// <param name="propertyType">Property type.</param>
	/// <param name="propertyValue">Value that could not be parsed into
	/// property type.</param>
	/// <param name="innerException">Optional inner <see cref="Exception"/>.</param>
	/// <returns><see cref="JsonException"/>.</returns>
	public static JsonException GenerateJsonException_DeserializeUnableToConvertValue(
		Type propertyType,
		string propertyValue,
		Exception? innerException = null)
	{
		Debug.Assert(s_JsonException_AppendPathInformation != null);

		JsonException jsonException = new JsonException(
			$"The JSON value '{propertyValue}' could not be converted to {propertyType}.",
			innerException);
		s_JsonException_AppendPathInformation?.SetValue(jsonException, true);
		return jsonException;
	}
}