Function failUnmappable

scripts/codegen/csharp.ts:297–305

* Schemas marked `.asOpaqueJson()` on the runtime side carry * `x-opaque-json: true`. These are the only shapes that legitimately surface * as opaque JSON in the SDK (mapped to `JsonElement` in C#). Anything else * that lacks an idiomatic mapping (untyped fields, non-discriminated unions, * etc.

(context: string, schema: JSONSchema7)

 * The predicate itself lives in {@link "./utils".isOpaqueJson} for reuse.
 */
function failUnmappable(context: string, schema: JSONSchema7): never {
    const summary = JSON.stringify(schema, (key, value) => (key === "description" ? undefined : value)).slice(0, 200);
    throw new Error(
        `C# codegen: cannot map schema to an idiomatic C# type (${context}). ` +
            `On the runtime side, either tighten the Zod schema to a typed shape, or — if it is genuinely free-form JSON — ` +
            `mark it \`.asOpaqueJson()\` so the schema emits \`x-opaque-json: true\` and the codegen maps it to JsonElement. ` +
            `Offending schema (truncated): ${summary}`,
    );
}

function requiresArgumentNullCheck(typeName: string, isRequired: boolean): boolean {
    return isRequired && !typeName.endsWith("?") && !isNonNullableCSharpValueType(typeName);