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v1.0.28: fix sync rewrite/delete loop, Avast-inspired icon

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Sync loop root-cause fixes (three independent bugs):

1. Folder change clears stale file states (AddPairViewModel): when
   localPath or remotePath changes on an existing pair, all
   SyncFileStateEntity records are wiped. Previously those stale records
   caused every sync to attempt DELETE_REMOTE on the old folder's files
   and to treat all new-folder files as changed — causing both the
   "deleting 32 files" loop and rewrites on every run.

2. Download stores null localModifiedAt (SyncEngine): SAF document
   cursors can return a stale mtime immediately after a write. Storing
   null forces the SKIP reconciliation pass on the next sync to read
   the actual walkFiles cursor value, breaking the download->changed->
   download loop caused by mtime inconsistency.

3. Second-precision mtime comparison (syncDecide): WebDAV RFC-1123 has
   1-second precision; FAT32 has 2-second precision. Comparing at
   millisecond level caused phantom "changed" detections after syncing
   to/from these systems. Now uses epochSecond for both local and remote.

Icon: three bold teal/red/yellow teardrop streaks (Avast palette) flying
into a white cloud centre, on dark charcoal background.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Amir Khodak
2026-05-25 04:18:13 +00:00
parent dc2a0b2c68
commit 34fb06a673
5 changed files with 113 additions and 81 deletions
Download Patch File Download Diff File Expand all files Collapse all files
app/src/main/kotlin/com/syncflow/domain/sync/SyncEngine.kt
+13 -4
View File
@@ -126,7 +126,9 @@ class SyncEngine @Inject constructor(
logEvent(pair.id, SyncEventType.FILE_DOWNLOADED, rel, null, bytes)
FileOutcome(downloaded = 1, bytesTransferred = bytes,
newState = buildState(pair.id, rel,
LocalFileInfo(rel, remote!!.sizeBytes, localMtime), remoteAfterTransfer = remote))
LocalFileInfo(rel, remote!!.sizeBytes, localMtime),
remoteAfterTransfer = remote,
storeLocalMtime = false))
}
SyncDecision.DELETE_LOCAL -> {
accessor.delete(rel)
@@ -203,10 +205,13 @@ class SyncEngine @Inject constructor(
rel: String,
local: LocalFileInfo?,
remoteAfterTransfer: RemoteFile?,
storeLocalMtime: Boolean = true,
) = SyncFileStateEntity(
syncPairId = pairId,
relativePath = rel,
localModifiedAt = local?.lastModifiedMs?.let { Instant.ofEpochMilli(it) },
// When storeLocalMtime=false, leave localModifiedAt null so the SKIP reconciliation
// pass on the next sync reads it from the walkFiles cursor (avoids SAF stale-mtime loops).
localModifiedAt = if (storeLocalMtime) local?.lastModifiedMs?.let { Instant.ofEpochMilli(it) } else null,
localSizeBytes = local?.sizeBytes ?: 0L,
localHash = null,
remoteModifiedAt = remoteAfterTransfer?.modifiedAt,
@@ -236,12 +241,16 @@ internal fun syncDecide(
// Treat null known timestamps as "not yet recorded" — don't treat as changed.
// The SKIP reconciliation pass will fill them in on the next sync.
// Use second-precision for both sides: FAT32 has 2-second mtime resolution, WebDAV
// RFC-1123 has 1-second resolution, so millisecond comparison causes phantom "changed"
// detections and rewrite loops after a fresh download/upload.
val localChanged = known == null ||
(localExists && known.localModifiedAt != null &&
local!!.lastModifiedMs != known.localModifiedAt.toEpochMilli())
local!!.lastModifiedMs / 1000 != known.localModifiedAt.epochSecond)
val remoteChanged = known == null ||
(remoteExists && known.remoteModifiedAt != null &&
(remote!!.etag != known.remoteEtag || remote.modifiedAt != known.remoteModifiedAt))
(remote!!.etag != known.remoteEtag ||
remote.modifiedAt.epochSecond != known.remoteModifiedAt.epochSecond))
return when {
!localExists && !remoteExists -> SyncDecision.SKIP
app/src/main/kotlin/com/syncflow/ui/addpair/AddPairViewModel.kt
+16 -1
View File
@@ -5,6 +5,7 @@ import androidx.lifecycle.SavedStateHandle
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import com.syncflow.data.db.CloudAccountDao
import com.syncflow.data.db.SyncFileStateDao
import com.syncflow.data.db.SyncPairDao
import com.syncflow.data.db.entities.CloudAccountEntity
import com.syncflow.data.db.entities.SyncPairEntity
@@ -58,6 +59,7 @@ data class AddPairUiState(
@HiltViewModel
class AddPairViewModel @Inject constructor(
private val syncPairDao: SyncPairDao,
private val fileStateDao: SyncFileStateDao,
private val accountDao: CloudAccountDao,
@ApplicationContext private val context: Context,
savedState: SavedStateHandle,
@@ -148,7 +150,20 @@ class AddPairViewModel @Inject constructor(
notifyOnComplete = s.notifyOnComplete, notifyOnError = s.notifyOnError,
isEnabled = true, lastSyncAt = null, lastSyncResult = SyncStatus.IDLE, pendingConflicts = 0,
)
if (editPairId == null) syncPairDao.insert(entity) else syncPairDao.update(entity)
if (editPairId == null) {
syncPairDao.insert(entity)
} else {
val existing = syncPairDao.getById(editPairId)
syncPairDao.update(entity)
// If local or remote folder changed, old file-state records no longer
// correspond to any real path — wipe them so the next sync starts fresh
// instead of trying to delete/re-upload stale paths.
if (existing != null &&
(existing.localPath != entity.localPath || existing.remotePath != entity.remotePath)
) {
fileStateDao.deleteForPair(editPairId)
}
}
}
.onSuccess {
if (s.scheduleType == ScheduleType.ON_CHANGE) FileWatchService.start(context)