From 8e2c33b4ddaff5865b4cc6fe0f493ad98ef61006 Mon Sep 17 00:00:00 2001
From: Gregor MacLennan <gmaclennan@awana.digital>
Date: Wed, 4 Nov 2026 23:35:06 +0000
Subject: [PATCH 1/2] test(sync): pin data progress across multiple syncing
 devices

---
 test/lib/sync.test.ts | 67 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 test/lib/sync.test.ts

diff --git a/test/lib/sync.test.ts b/test/lib/sync.test.ts
new file mode 100644
index 0000000..0d1293f
--- /dev/null
+++ b/test/lib/sync.test.ts
@@ -0,0 +1,67 @@
+/**
+ * @vitest-environment node
+ */
+import type { ComapeoProjectClientApi } from '@comapeo/ipc'
+import { describe, expect, it } from 'vitest'
+
+import { SyncStore, type SyncState } from '../../src/lib/sync.js'
+
+type DeviceCounts = Record<string, { want: number; wanted: number }>
+
+function createSyncState(devices: DeviceCounts): SyncState {
+	const remoteDeviceSyncState: SyncState['remoteDeviceSyncState'] = {}
+	for (const [deviceId, counts] of Object.entries(devices)) {
+		remoteDeviceSyncState[deviceId] = {
+			initial: { isSyncEnabled: true, want: 0, wanted: 0 },
+			data: { isSyncEnabled: true, ...counts },
+		}
+	}
+	return {
+		initial: { isSyncEnabled: true },
+		data: { isSyncEnabled: true },
+		remoteDeviceSyncState,
+	}
+}
+
+function createFakeProject(initialState: SyncState) {
+	let listener: ((state: SyncState) => void) | undefined
+	const project = {
+		$sync: {
+			getState: async () => initialState,
+			on: (_event: 'sync-state', fn: (state: SyncState) => void) => {
+				listener = fn
+			},
+			off: () => {
+				listener = undefined
+			},
+		},
+	}
+	return {
+		project: project as unknown as ComapeoProjectClientApi,
+		emitState: (state: SyncState) => listener?.(state),
+	}
+}
+
+describe('SyncStore data progress', () => {
+	it('is not complete while any syncing device still has blocks to exchange', async () => {
+		const { project, emitState } = createFakeProject(
+			createSyncState({
+				cloud: { want: 5, wanted: 0 },
+				phone: { want: 5, wanted: 0 },
+			}),
+		)
+		const store = new SyncStore(project)
+		const unsubscribe = store.subscribe(() => {})
+		await expect.poll(() => store.getStateSnapshot()).not.toBeNull()
+
+		emitState(
+			createSyncState({
+				cloud: { want: 5, wanted: 0 },
+				phone: { want: 0, wanted: 0 },
+			}),
+		)
+
+		expect(store.getDataProgressSnapshot()).toBe(0.5)
+		unsubscribe()
+	})
+})

From eb7458233649be15f0f39b87e311ffa37f4628c9 Mon Sep 17 00:00:00 2001
From: Gregor MacLennan <gmaclennan@awana.digital>
Date: Wed, 4 Nov 2026 23:35:19 +0000
Subject: [PATCH 2/2] fix(sync): sum remaining blocks across devices in data
 sync progress

---
 src/lib/sync.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lib/sync.ts b/src/lib/sync.ts
index 9d30362..9ad0ec3 100644
--- a/src/lib/sync.ts
+++ b/src/lib/sync.ts
@@ -61,7 +61,7 @@ export class SyncStore {
 			const existingMaxCount = this.#perDeviceMaxSyncCount.get(deviceId)
 
 			if (typeof existingMaxCount === 'number' && existingMaxCount > 0) {
-				currentSyncCount = getDataSyncCountForDevice(deviceSyncState)
+				currentSyncCount += getDataSyncCountForDevice(deviceSyncState)
 				totalMaxSyncCount += existingMaxCount
 			}
 		}