fix: Lock file handling.

Locking:
- Added a boolean flag to metadata items which indicates whether they are locally created lock files or not. This is required for correct handling in some places.
- Changed database schema version.
- Lock files are now not excluded from synchronization but pretended to be synchronized.
- On following synchronizations, they are excluded from local deletion due to not being found on the server.
- Also, they are ignored in the materialized item enumeration to avoid unnecessary server requests.

Logging:
- Removed subsystem property in file provider domain log messages because it is always the same anyway.
- Improved date formatting of file provider domain log messages.
- Messages are written to the unified logging system again in debug configuration builds.
- Messages with debug level are not written to log files unless it is a debug configuration build.
- Refined encoding of supported log detail types.

Key changes of this commit:
- FilesDatabaseManager.swift:661
- RemoteChangeObserver.swift:474
- Item+Delete.swift:29
- Item+LockFile.swift:137

Signed-off-by: Iva Horn <iva.horn@icloud.com>

Author: i2h3

Sources/NextcloudFileProviderKit/Database/FilesDatabaseManager.swift

@@ -40,7 +40,7 @@ public final class FilesDatabaseManager: Sendable {
         )
     }
 
-    private static let schemaVersion = SchemaVersion.addedLockTokenPropertyToRealmItemMetadata
+    private static let schemaVersion = SchemaVersion.addedIsLockFileOfLocalOriginToRealmItemMetadata
     let logger: FileProviderLogger
     let account: Account
 
@@ -558,6 +558,7 @@ public final class FilesDatabaseManager: Sendable {
 
             return nil
         }
+        
         return NSFileProviderItemIdentifier(parentDirectoryMetadata.ocId)
     }
 
@@ -578,6 +579,7 @@ public final class FilesDatabaseManager: Sendable {
             depth: .target,
             log: logger.log
         )
+        
         guard error == nil, let parentMetadata = metadatas?.first else {
             logger.error("Could not retrieve parent item identifier remotely.", [
                 .error: error,
@@ -602,61 +604,72 @@ public final class FilesDatabaseManager: Sendable {
         managedMaterialisedItemMetadatas(account: account).toUnmanagedResults()
     }
 
-    public func pendingWorkingSetChanges(
-        account: Account, since date: Date
-    ) -> (updated: [SendableItemMetadata], deleted: [SendableItemMetadata]) {
+    public func pendingWorkingSetChanges(account: Account, since date: Date) -> (updated: [SendableItemMetadata], deleted: [SendableItemMetadata]) {
         let accId = account.ncKitAccount
         let pending = managedMaterialisedItemMetadatas(account: accId).where { $0.syncTime > date }
         var updated = pending.where { !$0.deleted }.toUnmanagedResults()
         var deleted = pending.where { $0.deleted }.toUnmanagedResults()
-
         var handledUpdateOcIds = Set(updated.map(\.ocId))
+        
         updated
             .map {
                 var serverUrl = $0.serverUrl + "/" + $0.fileName
                 if serverUrl.last == "/" { serverUrl.removeLast() }
                 return serverUrl
             }
             .forEach { serverUrl in
-                logger.debug("Checking (updated) \(serverUrl)")
+                logger.debug("Checking updated item...", [.url: serverUrl])
 
                 itemMetadatas
                     .where { $0.serverUrl == serverUrl && $0.syncTime > date }
                     .forEach { metadata in
-                        logger.debug("Checking item: \(metadata.fileName)")
-
                         guard !handledUpdateOcIds.contains(metadata.ocId) else {
                             return
                         }
 
                         handledUpdateOcIds.insert(metadata.ocId)
                         let sendableMetadata = SendableItemMetadata(value: metadata)
+
                         if metadata.deleted {
                             deleted.append(sendableMetadata)
+                            logger.debug("Appended deleted item to working set changes.", [.item: metadata.ocId, .url: serverUrl])
                         } else {
                             updated.append(sendableMetadata)
+                            logger.debug("Appended updated item to working set changes.", [.item: metadata.ocId, .url: serverUrl])
                         }
-
-                        logger.debug("Appended item: \(metadata.fileName)")
                     }
             }
 
         var handledDeleteOcIds = Set(deleted.map(\.ocId))
+        
         deleted
-            .map {
+            .map { // assemble remote location
                 var serverUrl = $0.serverUrl + "/" + $0.fileName
-                if serverUrl.last == "/" { serverUrl.removeLast() }
+                
+                if serverUrl.last == "/" {
+                    serverUrl.removeLast()
+                }
+                
                 return serverUrl
             }
             .forEach { serverUrl in
-                logger.debug("Checking (deletion) \(serverUrl)")
-
-                itemMetadatas
-                    .where { $0.serverUrl.starts(with: serverUrl) && $0.syncTime > date }
-                    .forEach { metadata in
-                        guard !handledDeleteOcIds.contains(metadata.ocId) else { return }
-                        deleted.append(SendableItemMetadata(value: metadata))
+                logger.debug("Verifying deleted item...", [.url: serverUrl])
+
+                itemMetadatas.where {
+                    $0.serverUrl.starts(with: serverUrl) && $0.syncTime > date
+                }.forEach { metadata in
+                    guard metadata.isLockFileOfLocalOrigin == false else {
+                        logger.info("Excluding item from deletion because it is a lock file from local origin.", [.item: metadata])
+                        return
                     }
+                    
+                    guard !handledDeleteOcIds.contains(metadata.ocId) else {
+                        return
+                    }
+                    
+                    deleted.append(SendableItemMetadata(value: metadata))
+                    logger.debug("Appended deleted item to working set changes.", [.item: metadata.ocId, .url: serverUrl])
+                }
             }
 
         return (updated, deleted)

Sources/NextcloudFileProviderKit/Database/SchemaVersion.swift

@@ -8,4 +8,5 @@ enum SchemaVersion: UInt64 {
     case initial = 100
     case deletedLocalFileMetadata = 200
     case addedLockTokenPropertyToRealmItemMetadata = 201
+    case addedIsLockFileOfLocalOriginToRealmItemMetadata = 202
 }

Sources/NextcloudFileProviderKit/Enumeration/Enumerator+SyncEngine.swift

@@ -120,7 +120,6 @@ extension Enumerator {
         nextPage: EnumeratorPageResponse?,
         readError: NKError?
     ) {
-        let ncKitAccount = account.ncKitAccount
         let logger = FileProviderLogger(category: "Enumerator", log: log)
 
         logger.debug("Starting to read server URL.", [.url: serverUrl])