Fix app stream/timeline ordering desync and init lifecycle race (#73)

* fix(app): enforce canonical stream sequencing and init resolution * refactor: extract timeline and stream reducers to pure functions
2026-02-23 19:30:48 +07:00
parent 9b6f5e028c
commit a134132418
12 changed files with 1732 additions and 109 deletions
@@ -0,0 +1,64 @@
+import { describe, expect, it } from "vitest";
+import { classifySessionTimelineSeq } from "./session-timeline-seq-gate";
+
+describe("classifySessionTimelineSeq", () => {
+  it("accepts contiguous forward seq", () => {
+    expect(
+      classifySessionTimelineSeq({
+        cursor: { epoch: "epoch-1", endSeq: 4 },
+        epoch: "epoch-1",
+        seq: 5,
+      })
+    ).toBe("accept");
+  });
+
+  it("drops stale seq older than the current end", () => {
+    expect(
+      classifySessionTimelineSeq({
+        cursor: { epoch: "epoch-1", endSeq: 8 },
+        epoch: "epoch-1",
+        seq: 7,
+      })
+    ).toBe("drop_stale");
+  });
+
+  it("drops duplicate replay seq equal to the current end", () => {
+    expect(
+      classifySessionTimelineSeq({
+        cursor: { epoch: "epoch-1", endSeq: 8 },
+        epoch: "epoch-1",
+        seq: 8,
+      })
+    ).toBe("drop_stale");
+  });
+
+  it("drops epoch mismatch", () => {
+    expect(
+      classifySessionTimelineSeq({
+        cursor: { epoch: "epoch-1", endSeq: 4 },
+        epoch: "epoch-2",
+        seq: 5,
+      })
+    ).toBe("drop_epoch");
+  });
+
+  it("initializes when cursor is null", () => {
+    expect(
+      classifySessionTimelineSeq({
+        cursor: null,
+        epoch: "epoch-1",
+        seq: 1,
+      })
+    ).toBe("init");
+  });
+
+  it("classifies forward gaps", () => {
+    expect(
+      classifySessionTimelineSeq({
+        cursor: { epoch: "epoch-1", endSeq: 4 },
+        epoch: "epoch-1",
+        seq: 9,
+      })
+    ).toBe("gap");
+  });
+});