From 11270ff6945f6ea7a5d2f5c243e6fa7101e28689 Mon Sep 17 00:00:00 2001
From: Torsten Grote <t@grobox.de>
Date: Tue, 1 Oct 2024 16:49:00 -0300
Subject: [PATCH] Reset latest snapshot to avoid it getting stale

When switching to new storage that doesn't yet have any snapshots, we would otherwise keep the old latest snapshot around.
---
 .../java/com/stevesoltys/seedvault/repo/SnapshotManager.kt   | 3 +++
 .../com/stevesoltys/seedvault/repo/SnapshotManagerTest.kt    | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/app/src/main/java/com/stevesoltys/seedvault/repo/SnapshotManager.kt b/app/src/main/java/com/stevesoltys/seedvault/repo/SnapshotManager.kt
index 6d3bde26..15b2a931 100644
--- a/app/src/main/java/com/stevesoltys/seedvault/repo/SnapshotManager.kt
+++ b/app/src/main/java/com/stevesoltys/seedvault/repo/SnapshotManager.kt
@@ -47,6 +47,9 @@ internal class SnapshotManager(
      * currently available on the backend.
      */
     suspend fun onSnapshotsLoaded(handles: List<AppBackupFileType.Snapshot>): List<Snapshot> {
+        // first reset latest snapshot, otherwise we'd hang on to a stale one
+        // e.g. when switching to new storage without any snapshots
+        latestSnapshot = null
         return handles.mapNotNull { snapshotHandle ->
             val snapshot = try {
                 loadSnapshot(snapshotHandle)
diff --git a/app/src/test/java/com/stevesoltys/seedvault/repo/SnapshotManagerTest.kt b/app/src/test/java/com/stevesoltys/seedvault/repo/SnapshotManagerTest.kt
index ee712c7f..5104f5a6 100644
--- a/app/src/test/java/com/stevesoltys/seedvault/repo/SnapshotManagerTest.kt
+++ b/app/src/test/java/com/stevesoltys/seedvault/repo/SnapshotManagerTest.kt
@@ -23,6 +23,7 @@ import org.calyxos.seedvault.core.toHexString
 import org.junit.jupiter.api.Assertions.assertArrayEquals
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertNull
 import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.io.TempDir
@@ -75,6 +76,10 @@ internal class SnapshotManagerTest : TransportTest() {
 
         // snapshot with largest token is latest
         assertEquals(20, snapshotManager.latestSnapshot?.token)
+
+        // when switching storage and now not having any snapshots, we must clear latestSnapshot
+        snapshotManager.onSnapshotsLoaded(emptyList())
+        assertNull(snapshotManager.latestSnapshot)
     }
 
     @Test