fix(sync): skip duplicate status events (#1152)

* fix(sync): skip duplicate status events

* test(sync): cover duplicate idle statuses

---------

Co-authored-by: Isaac Sanchez <isanchez-hawkins@arize.com>
Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

packages/ui/src/sync/__tests__/event-reducer.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, test } from "bun:test"
-import type { Event, Part, PermissionRequest, QuestionRequest } from "@opencode-ai/sdk/v2/client"
+import type { Event, Part, PermissionRequest, QuestionRequest, SessionStatus } from "@opencode-ai/sdk/v2/client"
 import { applyDirectoryEvent } from "../event-reducer"
 import { INITIAL_STATE, type State } from "../types"
 
@@ -8,6 +8,7 @@ function state(overrides: Partial<State> = {}): State {
     ...INITIAL_STATE,
     message: {},
     part: {},
+    session_status: {},
     ...overrides,
   }
 }
@@ -87,6 +88,68 @@ describe("applyDirectoryEvent", () => {
     expect(result).toBe(true)
   })
 
+  test("skips duplicate session status events", () => {
+    const draft = state()
+    const busyStatus = { type: "busy" } as SessionStatus
+    const event = {
+      type: "session.status",
+      properties: { sessionID: "ses_1", status: busyStatus },
+    } as Event
+
+    expect(applyDirectoryEvent(draft, event)).toBe(true)
+    const statusRef = draft.session_status.ses_1
+
+    expect(applyDirectoryEvent(draft, event)).toBe(false)
+    expect(draft.session_status.ses_1).toBe(statusRef)
+  })
+
+  test("skips duplicate session idle events", () => {
+    const draft = state()
+    const event = {
+      type: "session.idle",
+      properties: { sessionID: "ses_1" },
+    } as Event
+
+    expect(applyDirectoryEvent(draft, event)).toBe(true)
+    const statusRef = draft.session_status.ses_1
+
+    expect(applyDirectoryEvent(draft, event)).toBe(false)
+    expect(draft.session_status.ses_1).toBe(statusRef)
+  })
+
+  test("skips duplicate session error idle-state events", () => {
+    const draft = state()
+    const event = {
+      type: "session.error",
+      properties: { sessionID: "ses_1" },
+    } as Event
+
+    expect(applyDirectoryEvent(draft, event)).toBe(true)
+    const statusRef = draft.session_status.ses_1
+
+    expect(applyDirectoryEvent(draft, event)).toBe(false)
+    expect(draft.session_status.ses_1).toBe(statusRef)
+  })
+
+  test("detects retry status metadata changes", () => {
+    const draft = state({
+      session_status: {
+        ses_1: { type: "retry", attempt: 1, message: "rate limited", next: 10 } as SessionStatus,
+      },
+    })
+
+    const event = {
+      type: "session.status",
+      properties: {
+        sessionID: "ses_1",
+        status: { type: "retry", attempt: 2, message: "rate limited", next: 20 } as SessionStatus,
+      },
+    } as Event
+
+    expect(applyDirectoryEvent(draft, event)).toBe(true)
+    expect((draft.session_status.ses_1 as Extract<SessionStatus, { type: "retry" }>).attempt).toBe(2)
+  })
+
   test("updates permission request arrays immutably", () => {
     const initialPermissions = [
       { id: "perm_1", sessionID: "ses_1" } as PermissionRequest,

packages/ui/src/sync/event-reducer.ts

@@ -90,6 +90,18 @@ function shouldPreserveExistingPart(previous: Part, next: Part): boolean {
   return false
 }
 
+function areSessionStatusesEqual(left: SessionStatus | undefined, right: SessionStatus): boolean {
+  if (left === right) return true
+  if (!left || left.type !== right.type) return false
+  if (left.type === "retry") {
+    return right.type === "retry"
+      && left.attempt === right.attempt
+      && left.message === right.message
+      && left.next === right.next
+  }
+  return true
+}
+
 // ---------------------------------------------------------------------------
 // Global events
 // ---------------------------------------------------------------------------
@@ -219,19 +231,30 @@ export function applyDirectoryEvent(
 
     case "session.status": {
       const props = event.properties as { sessionID: string; status: SessionStatus }
+      if (areSessionStatusesEqual(draft.session_status[props.sessionID], props.status)) {
+        return false
+      }
       draft.session_status[props.sessionID] = props.status
       return true
     }
 
     case "session.idle": {
       const props = event.properties as { sessionID: string }
-      draft.session_status[props.sessionID] = { type: "idle" }
+      const status = { type: "idle" } as const
+      if (areSessionStatusesEqual(draft.session_status[props.sessionID], status)) {
+        return false
+      }
+      draft.session_status[props.sessionID] = status
       return true
     }
 
     case "session.error": {
       const props = event.properties as { sessionID: string }
-      draft.session_status[props.sessionID] = { type: "idle" }
+      const status = { type: "idle" } as const
+      if (areSessionStatusesEqual(draft.session_status[props.sessionID], status)) {
+        return false
+      }
+      draft.session_status[props.sessionID] = status
       return true
     }