Function tryEmitPyRefBasedDiscriminatedUnion

scripts/codegen/python.ts:1562–1644

* Emit a "$ref-based discriminated union" — a Python equivalent of the * polymorphic hierarchies that TS / Rust / .NET / Go produce for the same * schema shape. Given a definition like * * "PermissionRequest": { "anyOf": [ {"$ref": "#/.../PermissionRequestShell"}, ... ] } * * where every v

(
    aliasName: string,
    resolved: JSONSchema7,
    ctx: PyCodegenCtx
)

 * expected shape (caller falls back to other paths).
 */
function tryEmitPyRefBasedDiscriminatedUnion(
    aliasName: string,
    resolved: JSONSchema7,
    ctx: PyCodegenCtx
): PyResolvedType | undefined {
    const variants = (resolved.anyOf ?? resolved.oneOf) as JSONSchema7[] | undefined;
    if (!Array.isArray(variants) || variants.length < 2) return undefined;

    const variantRefNames: string[] = [];
    for (const v of variants) {
        if (!v || typeof v !== "object") return undefined;
        const ref = (v as JSONSchema7).$ref;
        if (typeof ref !== "string" || !ref.startsWith("#/definitions/")) {
            return undefined;
        }
        variantRefNames.push(refTypeName(ref, ctx.definitions));
    }

    const resolvedVariants = variants.map(
        (v) =>
            resolveObjectSchema(v, ctx.definitions) ??
            resolveSchema(v, ctx.definitions) ??
            (v as JSONSchema7)
    );
    if (resolvedVariants.some((rv) => !rv || rv.properties === undefined)) {
        return undefined;
    }
    const discriminator = findPyDiscriminator(resolvedVariants as JSONSchema7[]);
    if (!discriminator) return undefined;

    const variantTypeNames: string[] = [];
    const dispatch: Array<{ value: string; typeName: string }> = [];
    for (let i = 0; i < variants.length; i++) {
        const variantTypeName = toPascalCase(variantRefNames[i]);
        const variantSchema = resolveObjectSchema(variants[i], ctx.definitions);
        if (variantSchema) {
            emitPyClass(variantTypeName, variantSchema, ctx, variantSchema.description);
        }
        variantTypeNames.push(variantTypeName);
        const discProp = resolvedVariants[i].properties?.[discriminator.property] as JSONSchema7;
        dispatch.push({ value: String(discProp.const), typeName: variantTypeName });
    }

    if (!ctx.aliasesByName.has(aliasName)) {
        const lines: string[] = [];
        if (resolved.description) {
            lines.push(`# ${resolved.description}`);
        }
        lines.push(`${aliasName} = ${variantTypeNames.join(" | ")}`);
        ctx.aliasesByName.add(aliasName);
        ctx.aliases.push(lines.join("\n"));
        ctx.refBasedUnions.push({
            aliasName,
            discriminatorProp: discriminator.property,
            dispatch,
        });
    }