fix: getSpecs mutated defaultOptions if passed #211 (#212)

* fix: getSpecs mutated defaultOptions if passed #211

this caused parameters to be added to all following specs with the same method if defaultOptions are passed to openAPIRouteHandler

fix #211

* fix: added tests

---------

Co-authored-by: mathuraditya724 <mathuraditya724@gmail.com>

Author: matzehecht

src/__tests__/zodv4.test.ts

@@ -148,4 +148,42 @@ describe("zod v4", () => {
 
     expect(specs).toMatchSnapshot();
   });
+
+  it("defaultOptions should not cause parameter pollution between routes", async () => {
+    const app = new Hono()
+      .get(
+        "/hello",
+        describeRoute({}),
+        validator("query", z.object({ name: z.string() })),
+        (c) => {
+          const { name } = c.req.valid("query");
+          return c.text(`Hello, ${name}!`);
+        },
+      )
+      .get(
+        "/world",
+        describeRoute({}),
+        validator("query", z.object({ greeting: z.string() })),
+        (c) => {
+          const { greeting } = c.req.valid("query");
+          return c.text(`${greeting}, world!`);
+        },
+      );
+
+    const specs = await generateSpecs(app, {
+      defaultOptions: {
+        GET: {},
+      },
+    });
+
+    // Verify /hello only has 'name' parameter
+    const helloParams = specs.paths["/hello"]?.get?.parameters;
+    expect(helloParams).toHaveLength(1);
+    expect(helloParams?.[0]).toMatchObject({ name: "name", in: "query" });
+
+    // Verify /world only has 'greeting' parameter (not 'name' from /hello)
+    const worldParams = specs.paths["/world"]?.get?.parameters;
+    expect(worldParams).toHaveLength(1);
+    expect(worldParams?.[0]).toMatchObject({ name: "greeting", in: "query" });
+  });
 });

src/handler.ts

@@ -166,8 +166,9 @@ async function generatePaths<
       }
     }
 
-    const defaultOptionsForThisMethod =
-      ctx.options.defaultOptions?.[routeMethod];
+    const defaultOptionsForThisMethod = ctx.options.defaultOptions?.[
+      routeMethod
+    ] && { ...ctx.options.defaultOptions[routeMethod] };
 
     const { schema: routeSpecs, components = {} } = await getSpec(
       middlewareHandler,
@@ -253,7 +254,7 @@ async function getSpec(
 
   const result = await middlewareHandler.toOpenAPISchema();
   const docs: Pick<OpenAPIV3_1.OperationObject, "parameters" | "requestBody"> =
-    defaultOptions ?? {};
+    { ...defaultOptions };
 
   if (
     middlewareHandler.target === "form" ||