fix: log error when misconfigured (#7584)

packages/better-auth/src/context/create-context.test.ts

@@ -595,6 +595,7 @@ describe("base context creation", () => {
 		});
 
 		it("should return false when generateId is false", async () => {
+			const fn = vi.spyOn(console, "error").mockImplementation(vi.fn());
 			const res = await initBase({
 				advanced: {
 					database: {
@@ -602,6 +603,10 @@ describe("base context creation", () => {
 					},
 				},
 			});
+			expect(fn).toHaveBeenCalled();
+			const regex = /Misconfiguration detected/;
+			expect(fn).toHaveBeenCalledWith(expect.stringMatching(regex));
+			fn.mockRestore();
 			const id = res.generateId({ model: "user" });
 			expect(id).toBe(false);
 		});

packages/better-auth/src/context/create-context.ts

@@ -112,6 +112,18 @@ export async function createAuthContext(
 		);
 	}
 
+	if (
+		adapter.id === "memory" &&
+		options.advanced?.database?.generateId === false
+	) {
+		logger.error(
+			`[better-auth] Misconfiguration detected.
+You are using the memory DB with generateId: false.
+This will cause no id to be generated for any model.
+Most of the features of Better Auth will not work correctly.`,
+		);
+	}
+
 	const secret =
 		options.secret ||
 		env.BETTER_AUTH_SECRET ||