fix(config): avoid serialization warning when primitives have prototy…

…pe changed (#2902)

src/core/config/resolvers/runtime-config.ts

@@ -39,15 +39,13 @@ function provideFallbackValues(obj: Record<string, any>) {
 }
 
 function checkSerializableRuntimeConfig(obj: any, path: string[] = []) {
+  if (isPrimitiveValue(obj)) {
+    return;
+  }
+
   for (const key in obj) {
     const value = obj[key];
-    if (
-      value === null ||
-      typeof value === "string" ||
-      value === undefined ||
-      typeof value === "number" ||
-      typeof value === "boolean"
-    ) {
+    if (value === null || value === undefined || isPrimitiveValue(value)) {
       continue;
     }
 
@@ -67,3 +65,11 @@ function checkSerializableRuntimeConfig(obj: any, path: string[] = []) {
     }
   }
 }
+
+function isPrimitiveValue(value: any) {
+  return (
+    typeof value === "string" ||
+    typeof value === "number" ||
+    typeof value === "boolean"
+  );
+}

test/unit/runtime-config.test.ts

@@ -0,0 +1,62 @@
+import { describe, expect, it, vi } from "vitest";
+import { normalizeRuntimeConfig } from "../../src/core/config/resolvers/runtime-config";
+import type { NitroConfig } from "nitropack/types";
+
+const defaultRuntimeConfig = {
+  textProperty: "value",
+  numberProperty: 42,
+  booleanProperty: true,
+  arrayProperty: ["A", "B", "C"],
+  objectProperty: {
+    innerProperty: "value",
+  },
+  mixedArrayProperty: [
+    "A",
+    "B",
+    {
+      inner: {
+        innerProperty: "value",
+      },
+    },
+  ],
+};
+
+const nitroConfig: NitroConfig = {
+  runtimeConfig: defaultRuntimeConfig,
+  baseURL: "https://example.com",
+  experimental: {
+    envExpansion: false,
+  },
+};
+
+describe("normalizeRuntimeConfig", () => {
+  it("should not warn on a serializable runtime config", () => {
+    const warnSpy = vi.spyOn(console, "warn");
+    normalizeRuntimeConfig(nitroConfig);
+    expect(warnSpy).not.toHaveBeenCalled();
+  });
+
+  it("should not warn when primitive prototype is changed", () => {
+    const warnSpy = vi.spyOn(console, "warn");
+
+    // https://github.com/nitrojs/nitro/pull/2902
+    (String.prototype as any).brokenFunction = () => undefined;
+
+    normalizeRuntimeConfig(nitroConfig);
+    expect(warnSpy).not.toHaveBeenCalled();
+
+    delete (String.prototype as any).brokenFunction;
+  });
+
+  it("should throw a warning when runtimeConfig is not serializable", () => {
+    const warnSpy = vi.spyOn(console, "warn");
+    normalizeRuntimeConfig({
+      ...nitroConfig,
+      runtimeConfig: {
+        ...defaultRuntimeConfig,
+        brokenProperty: new Map(),
+      },
+    });
+    expect(warnSpy).toHaveBeenCalled();
+  });
+});