Push fails with HTTP 422 DataSyncError for invalid MBTiles file (zero-padded, 7.52 GB)

[RastoHu]

Description

When pushing a project containing an invalid MBTiles file (valid SQLite header, but ~7 GB of null bytes padding, czech.mbtiles) via the Mergin Maps QGIS plugin, the push fails with HTTP 422 DataSyncError.

Note: uploading the same file via the web dashboard (Files tab → Upload) succeeds without error.

Related: MerginMaps/python-api-client#303
Test data: https://drive.google.com/drive/folders/1qfp9ntxGJjbfKPu9_sY9fXVnSzb_T5Hc?usp=sharing

Environment
[x] Staging [ ] PROD

Application (+ app version, build, operating system)

• QGIS 3.44.7-Solothurn + Mergin Maps QGIS plugin d-146211
• macOS Tahoe 26.3

Steps to reproduce

1. Obtain or create an MBTiles file with a valid SQLite header but padded with ~7 GB of null bytes (total size ~7.52 GB)
2. Add the file to a Mergin Maps project in QGIS
3. Push the project via the Mergin Maps plugin

Actual results
Push fails with: "There are either corrupted files or it is not possible to create version with provided geopackage data" (HTTP 422, DataSyncError)

Expected results
TBD

Screenshots or logs

2026-06-18 20:57:27,319 --- push finish failed! Detail: There are either corrupted files or it is not possible to create version with provided geopackage data (DataSyncError) HTTP Error: 422 URL: https://app.dev.merginmaps.com/v2/projects/0b9bcb92-0cf2-44b2-99af-94230df3f995/versions Method: POST Error code: DataSyncError

Conclusion
Created by Claude and supervised by a human test analyst.

[RastoHu]

Similar issue when pushing invalid .gpkg file (test_4_9gib_invalid.gpkg)

Traceback (most recent call last):

  File "/Users/rastoh/Library/Application Support/QGIS/QGIS3/profiles/Rasto Lutra/python/plugins/Mergin/sync_dialog.py", line 178, in push_start_internal
    self.job = push_project_async(self.mergin_client, self.target_dir)

  File "/Users/rastoh/Library/Application Support/QGIS/QGIS3/profiles/Rasto Lutra/python/plugins/Mergin/mergin/client_push.py", line 350, in push_project_async
    mp.copy_versioned_file_for_upload(f, tmp_dir.name)

  File "/Users/rastoh/Library/Application Support/QGIS/QGIS3/profiles/Rasto Lutra/python/plugins/Mergin/mergin/merginproject.py", line 488, in copy_versioned_file_for_upload
    self.geodiff.make_copy_sqlite(self.fpath(path), tmp_file)

  File "/Users/rastoh/Library/Application Support/QGIS/QGIS3/profiles/Rasto Lutra/python/plugins/Mergin/mergin/deps/pygeodiff/main.py", line 318, in make_copy_sqlite
    return self.clib.make_copy_sqlite(self.context, src, dst)

  File "/Users/rastoh/Library/Application Support/QGIS/QGIS3/profiles/Rasto Lutra/python/plugins/Mergin/mergin/deps/pygeodiff/geodifflib.py", line 476, in make_copy_sqlite
    self._parse_return_code(context, res, "make_copy_sqlite")

  File "/Users/rastoh/Library/Application Support/QGIS/QGIS3/profiles/Rasto Lutra/python/plugins/Mergin/mergin/deps/pygeodiff/geodifflib.py", line 176, in _parse_return_code
    raise GeoDiffLibError(msg)

Mergin.mergin.deps.pygeodiff.geodifflib.GeoDiffLibError: Error in make_copy_sqlite:
MakeCopySqlite: backup failed: file is not a database