Function generatePolymorphicClasses

scripts/codegen/csharp.ts:812–857

* Generate a polymorphic base class and derived classes for a discriminated union.

(
    baseClassName: string,
    discriminatorProperty: string,
    variants: JSONSchema7[],
    knownTypes: Map<string, string>,
    nestedClasses: Map<string, string>,
    enumOutput: string[],
    description?: string,
    propertyResolver?: PropertyTypeResolver,
    experimental = false,
    options: DiscriminatedUnionGenerationOptions = {}
)

 * Generate a polymorphic base class and derived classes for a discriminated union.
 */
function generatePolymorphicClasses(
    baseClassName: string,
    discriminatorProperty: string,
    variants: JSONSchema7[],
    knownTypes: Map<string, string>,
    nestedClasses: Map<string, string>,
    enumOutput: string[],
    description?: string,
    propertyResolver?: PropertyTypeResolver,
    experimental = false,
    options: DiscriminatedUnionGenerationOptions = {}
): string {
    const resolver = propertyResolver ?? resolveSessionPropertyType;
    const lines: string[] = [];
    const discriminatorInfo = findDiscriminator(variants)!;
    const renamedBase = applyTypeRename(baseClassName);

    lines.push(...xmlDocCommentWithFallback(description, `Polymorphic base type discriminated by <c>${escapeXml(discriminatorProperty)}</c>.`, ""));
    if (experimental) pushExperimentalAttribute(lines);
    lines.push(`[JsonPolymorphic(`);
    lines.push(`    TypeDiscriminatorPropertyName = "${discriminatorProperty}",`);
    lines.push(`    UnknownDerivedTypeHandling = JsonUnknownDerivedTypeHandling.FallBackToBaseType)]`);

    for (const { value } of discriminatorInfo.mapping.values()) {
        const constValue = String(value);
        const derivedClassName = applyTypeRename(`${baseClassName}${toPascalCase(constValue)}`);
        lines.push(`[JsonDerivedType(typeof(${derivedClassName}), "${escapeCSharpStringLiteral(constValue)}")]`);
    }

    lines.push(`public partial class ${renamedBase}`);
    lines.push(`{`);
    lines.push(`    /// <summary>The type discriminator.</summary>`);
    lines.push(`    [JsonPropertyName("${discriminatorProperty}")]`);
    lines.push(`    public virtual string ${toPascalCase(discriminatorProperty)} { get; set; } = string.Empty;`);
    lines.push(`}`);
    lines.push("");

    for (const { value, schema } of discriminatorInfo.mapping.values()) {
        const constValue = String(value);
        const derivedClassName = applyTypeRename(`${baseClassName}${toPascalCase(constValue)}`);
        const derivedCode = generateDerivedClass(derivedClassName, renamedBase, discriminatorProperty, constValue, schema, knownTypes, nestedClasses, enumOutput, resolver, experimental, options);
        nestedClasses.set(derivedClassName, derivedCode);
    }

    return lines.join("\n");
}

/**
 * Generate a derived class for a discriminated union variant.