Fix Go and Rust code generators (#1596)

Update the Go generator to avoid discriminator method collisions only when a generated variant field would otherwise conflict. Update the Rust generator to keep RPC methods using internal schemas crate-private and allow intentionally unused generated internal items.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: stephentoub

rust/src/generated/api_types.rs

@@ -1,6 +1,7 @@
 //! Auto-generated from api.schema.json — do not edit manually.
 
 #![allow(clippy::large_enum_variant)]
+#![allow(dead_code)]
 
 use std::collections::HashMap;
 

rust/src/generated/rpc.rs

@@ -7,6 +7,7 @@
 
 #![allow(missing_docs)]
 #![allow(clippy::too_many_arguments)]
+#![allow(dead_code)]
 
 use super::api_types::{rpc_methods, *};
 use super::session_events::SessionMode;

scripts/codegen/go.ts

@@ -1731,6 +1731,27 @@ function goVariantMatchFunctionLines(
     return lines;
 }
 
+function goDiscriminatorMethodName(
+    typeName: string,
+    discriminatorProp: string,
+    discGoName: string,
+    variants: GoDiscriminatedUnionVariant[],
+    ctx: GoCodegenCtx
+): string {
+    const collidesWithVariantField = variants.some((variant) => {
+        const resolved = resolveSchema(variant.schema, ctx.definitions) ?? variant.schema;
+        const objectSchema = resolveObjectSchema(resolved, ctx.definitions) ?? resolved;
+        return Object.keys(objectSchema.properties ?? {}).some((propName) => {
+            if (propName === discriminatorProp) {
+                return variant.discriminatorValues.length > 1 && discGoName === "Discriminator";
+            }
+            return toGoFieldName(propName) === discGoName;
+        });
+    });
+
+    return collidesWithVariantField ? `${toGoUnexportedIdentifier(typeName)}${discGoName}` : discGoName;
+}
+
 /**
  * Emit a Go interface for a discriminated union (anyOf with const discriminator).
  */
@@ -1748,7 +1769,7 @@ function emitGoFlatDiscriminatedUnion(
     const mapping = discriminator.mapping;
     const unionVariants = [...discriminator.variants].sort((left, right) => compareGoTypeNames(left.typeName, right.typeName));
     const discGoName = toGoFieldName(discriminatorProp);
-    const discriminatorMethodName = discGoName;
+    const discriminatorMethodName = goDiscriminatorMethodName(typeName, discriminatorProp, discGoName, unionVariants, ctx);
     let discEnumName: string | undefined;
     let discGoType = "bool";
     if (discriminator.valueKind === "string") {

scripts/codegen/rust.ts

@@ -1545,6 +1545,7 @@ function generateApiTypesCode(
 	out.push("//! Auto-generated from api.schema.json — do not edit manually.");
 	out.push("");
 	out.push("#![allow(clippy::large_enum_variant)]");
+	out.push("#![allow(dead_code)]");
 	out.push("");
 	out.push("use std::collections::HashMap;");
 	out.push("");
@@ -1776,6 +1777,17 @@ function getResultTypeName(
 	return `${toPascalCase(method.rpcMethod)}Result`;
 }
 
+function methodUsesInternalSchema(
+	schema: JSONSchema7 | null | undefined,
+	defCollections: DefinitionCollections,
+): boolean {
+	if (!schema) return false;
+
+	const nonNullable = getNullableInner(schema) ?? schema;
+	const resolved = resolveSchema(nonNullable, defCollections) ?? nonNullable;
+	return isSchemaInternal(resolved);
+}
+
 function pushNamespaceMethodBody(
 	out: string[],
 	constName: string,
@@ -1884,7 +1896,12 @@ function emitNamespaceMethod(
 	};
 
 	const paramArg = hasParams ? `, params: ${paramsTypeName}` : "";
-	const fnVis = method.visibility === "internal" ? "pub(crate)" : "pub";
+	const fnVis =
+		method.visibility === "internal" ||
+		methodUsesInternalSchema(method.params, defCollections) ||
+		methodUsesInternalSchema(method.result, defCollections)
+			? "pub(crate)"
+			: "pub";
 
 	if (hasParams && paramsInfo.optional) {
 		out.push(...buildDocs(false));
@@ -1949,6 +1966,7 @@ function generateRpcCode(apiSchema: ApiSchema): string {
 	out.push("");
 	out.push("#![allow(missing_docs)]");
 	out.push("#![allow(clippy::too_many_arguments)]");
+	out.push("#![allow(dead_code)]");
 	out.push("");
 	out.push("use super::api_types::{rpc_methods, *};");
 	const externalTypeRefs = new Map<string, Set<string>>();