From 25527bb1d75dbd3349ae2746e1d56a695e33904b Mon Sep 17 00:00:00 2001
From: Gustavo Valverde <g.valverde02@gmail.com>
Date: Fri, 20 Mar 2026 07:35:12 +0000
Subject: [PATCH] fix: make Endpoint properties readonly and fix OpenAPI schema
 types
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Two type-level fixes that affect consumers using strict TypeScript:

1. Make `options` and `path` on `Endpoint` type readonly.

   These properties were mutable, making type parameters like `Meta`
   invariant. This prevented concrete endpoint types (e.g.,
   `Endpoint<..., { SERVER_ONLY: true }, ...>`) from being assigned
   to index signatures using bare `Endpoint`.

   Making them readonly makes `Meta`, `Method`, and `Path` covariant
   (read-only positions only), fixing the variance issue.

2. Add explicit `| undefined` to optional properties in
   `OpenAPIParameter.schema`.

   With `exactOptionalPropertyTypes: true`, `format?: string` means
   "absent or string" but NOT "explicitly undefined". When endpoints
   infer `format` as `string | undefined` (e.g., from optional zod
   fields), this causes a type mismatch. Adding `| undefined` makes
   the types compatible under strict optional property checking.

Runtime behavior is unchanged — these are type-level-only fixes.
---
 packages/better-call/src/endpoint.ts | 8 ++++----
 packages/better-call/src/openapi.ts  | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/packages/better-call/src/endpoint.ts b/packages/better-call/src/endpoint.ts
index fcb4851..96a9525 100644
--- a/packages/better-call/src/endpoint.ts
+++ b/packages/better-call/src/endpoint.ts
@@ -252,11 +252,11 @@ export type Endpoint<
 	(
 		context?: InputContext<Path, Method, Body, Query, false, false>,
 	): Promise<Awaited<R>>;
-	options: Omit<EndpointRuntimeOptions, "method" | "metadata"> & {
-		method: Method;
-		metadata?: Meta;
+	readonly options: Omit<EndpointRuntimeOptions, "method" | "metadata"> & {
+		readonly method: Method;
+		readonly metadata?: Meta;
 	};
-	path: Path;
+	readonly path: Path;
 };
 
 // Path + options + handler overload
diff --git a/packages/better-call/src/openapi.ts b/packages/better-call/src/openapi.ts
index c71c037..366ffb1 100644
--- a/packages/better-call/src/openapi.ts
+++ b/packages/better-call/src/openapi.ts
@@ -16,15 +16,15 @@ export interface OpenAPIParameter {
 	required?: boolean;
 	schema?: {
 		type: OpenAPISchemaType;
-		format?: string;
+		format?: string | undefined;
 		items?: {
 			type: OpenAPISchemaType;
 		};
 		enum?: string[];
 		minLength?: number;
-		description?: string;
-		default?: string;
-		example?: string;
+		description?: string | undefined;
+		default?: string | undefined;
+		example?: string | undefined;
 	};
 }