feat(protocol): define streamed diff revisions and resolve tag bases

packages/protocol/src/messages.diff.test.ts

@@ -0,0 +1,24 @@
+import { expect, test } from "vitest";
+import { DiffSubscribeRequestSchema, DiffSubscribeResponseSchema } from "./messages.js";
+
+test("accepts explicit endpoints without changing legacy schemas", () => {
+  const request = {
+    type: "diff.subscribe.request",
+    requestId: "r",
+    cwd: "/repo",
+    base: { kind: "rev", rev: "v1" },
+    head: { kind: "worktree" },
+    mergeBase: true,
+    highlight: false,
+  };
+  expect(DiffSubscribeRequestSchema.parse(request)).toEqual(request);
+  expect(
+    DiffSubscribeRequestSchema.safeParse({ ...request, base: { kind: "unknown" } }).success,
+  ).toBe(false);
+  expect(
+    DiffSubscribeResponseSchema.safeParse({
+      type: "diff.subscribe.response",
+      payload: { requestId: "r", subscriptionId: "s", slot: 256, error: null },
+    }).success,
+  ).toBe(false);
+});