refactor: delete the compatibility config surface

packages/styles/test/config.test.ts

@@ -7,7 +7,6 @@ import {
   resolveProfile,
   loadEnv,
   renderStyles,
-  resolveCompatibility,
   validateAppConfig,
   explainAppConfig,
 } from "../src/index.ts";
@@ -16,18 +15,6 @@ afterEach(() => {
   delete process.env.WRNEXUS_PROFILE;
 });
 
-test("compatibility dates pin behavior and reject invalid or future policies", () => {
-  expect(
-    resolveCompatibility({ compatibilityDate: "2026-08-02", frameworkBehaviour: 1 }),
-  ).toMatchObject({ needsUpgrade: false, future: false, effectiveBehaviour: 1 });
-  expect(validateAppConfig({ compatibilityDate: "2026-02-31" })).toContainEqual(
-    expect.objectContaining({ path: "compatibilityDate", severity: "error" }),
-  );
-  expect(validateAppConfig({ frameworkBehaviour: 2 })).toContainEqual(
-    expect.objectContaining({ severity: "error" }),
-  );
-});
-
 test("observability config requires bounded sampling and a valid OTLP endpoint", () => {
   expect(validateAppConfig({ observability: { sampleRate: Number.NaN } })).toContainEqual(
     expect.objectContaining({ path: "observability.sampleRate", severity: "error" }),

packages/styles/test/removed-config-keys.test.ts

@@ -0,0 +1,28 @@
+import { expect, test } from "bun:test";
+import { validateAppConfig } from "../src/config.ts";
+
+// A stale config must fail loudly. Silently ignoring a removed key leaves
+// someone believing a flag still applies.
+const REMOVED = [
+  { key: "compatibilityDate", config: { compatibilityDate: "2026-08-02" } },
+  { key: "frameworkBehaviour", config: { frameworkBehaviour: 1 } },
+  { key: "functions", config: { functions: { legacyDefaultRuntime: "current" } } },
+  { key: "compatibility", config: { compatibility: { legacyEmit: false } } },
+];
+
+for (const { key, config } of REMOVED) {
+  test(`a config still setting "${key}" is rejected with a message naming it`, () => {
+    const issues = validateAppConfig(config as never);
+    const match = issues.find((issue) => issue.path === key || issue.path.startsWith(`${key}.`));
+
+    expect(match).toBeDefined();
+    expect(match!.severity).toBe("error");
+    expect(match!.message.toLowerCase()).toContain("removed");
+  });
+}
+
+test("a config without those keys is accepted", () => {
+  const issues = validateAppConfig({} as never);
+
+  expect(issues.filter((issue) => issue.severity === "error")).toEqual([]);
+});