fix(libsync): refresh lock state after 423 upload errors

Force remote rediscovery on both 412 and 423 upload errors so the lock
state cleared from the journal is refreshed from the server, not only the
bad etag on 412. Strengthen the 412 test to assert the parent folder etag
is invalidated.

Assisted-by: Claude Code:claude-opus-4-8
Signed-off-by: Camila Ayres <hello@camilasan.com>

Author: camilasan

src/libsync/propagateupload.cpp

@@ -690,8 +690,9 @@ void PropagateUploadFileCommon::commonErrorHandling(AbstractNetworkJob *job)
     qCWarning(lcPropagateUpload) << replyContent; // display the XML error in the debug
 
     if (_item->_httpErrorCode == 412 || _item->_httpErrorCode == 423) {
-        // 412 or 423 can mean a stale lock token after the path moved under a renamed
-        // parent. Clear it so the next sync does not retry with an invalid token.
+        // 412 (precondition failed) and 423 (locked) can both follow a stale lock token
+        // after the path moved under a renamed parent. Clear it so the next sync does not
+        // retry with an invalid token.
         if (!_item->_lockToken.isEmpty()) {
             SyncJournalFileRecord record;
             if (propagator()->_journal->getFileRecord(_item->_file, &record) && record.isValid()) {
@@ -705,9 +706,9 @@ void PropagateUploadFileCommon::commonErrorHandling(AbstractNetworkJob *job)
             _item->_locked = SyncFileItem::LockStatus::UnlockedItem;
         }
 
-        if (_item->_httpErrorCode == 412) {
-            propagator()->_journal->schedulePathForRemoteDiscovery(_item->_file);
-        }
+        // Force a fresh read of the remote state so a bad etag (412) is dropped and the
+        // real lock state (423) is refreshed instead of the value cleared above.
+        propagator()->_journal->schedulePathForRemoteDiscovery(_item->_file);
         propagator()->_anotherSyncNeeded = true;
     }
 

test/testsyncmove.cpp

@@ -1491,6 +1491,13 @@ private slots:
         fakeFolder.serverErrorPaths().append("D/file.txt", 412);
         QVERIFY(!fakeFolder.syncOnce()); // Upload fails with 412.
 
+        // The 412 handler must invalidate the parent folder etag so the next sync
+        // rediscovers it instead of trusting the DB.
+        SyncJournalFileRecord parent;
+        QVERIFY(fakeFolder.syncJournal().getFileRecord(QByteArray("D"), &parent));
+        QVERIFY(parent.isValid());
+        QCOMPARE(parent._etag, QByteArrayLiteral("_invalid_"));
+
         // After clearing the error, the next sync must succeed.
         fakeFolder.serverErrorPaths().clear();
         [[maybe_unused]] const auto blacklistWiped = fakeFolder.syncJournal().wipeErrorBlacklist();