Failed to sync project [PROJECT_NAME] due to an unhandled exception.

[rphenriques]

Traceback (most recent call last):

File "/Users/rph/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/Mergin/sync_dialog.py", line 183, in push_start_internal
self.job = push_project_async(self.mergin_client, self.target_dir)

File "/Users/rph/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/Mergin/mergin/client_push.py", line 152, in push_project_async
resp = mc.post(

File "/Users/rph/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/Mergin/mergin/client.py", line 255, in post
return self._do_request(request)

File "/Users/rph/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/Mergin/mergin/client.py", line 198, in wrapper
return f(self, *args)

File "/Users/rph/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/Mergin/mergin/client.py", line 211, in _do_request
server_response = json.load(e)

File "/Applications/QGIS.app/Contents/MacOS/../Resources/python/json/init.py", line 293, in load
return loads(fp.read(),

File "/Applications/QGIS.app/Contents/MacOS/../Resources/python/json/init.py", line 346, in loads
return _default_decoder.decode(s)

File "/Applications/QGIS.app/Contents/MacOS/../Resources/python/json/decoder.py", line 337, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())

File "/Applications/QGIS.app/Contents/MacOS/../Resources/python/json/decoder.py", line 355, in raw_decode
raise JSONDecodeError("Expecting value", s, err.value) from None

json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

I am running QGIS on a Mac M1 with Mac OS 15.5 (24F74)
QGIS version | 3.40.1-Bratislava
QGIS code revision | 989853a7a31
 
Libraries
Qt version | 5.15.2
Python version | 3.9.5
GDAL/OGR version | 3.3.2
PROJ version | 8.1.1
EPSG Registry database version | v10.028 (2021-07-07)
GEOS version | 3.9.1-CAPI-1.14.2
SQLite version | 3.35.2
PDAL version | 2.3.0
PostgreSQL client version | unknown
SpatiaLite version | 5.0.1
QWT version | 6.1.6
QScintilla2 version | 2.11.5
OS version | macOS 15.5
 
Active Python plugins
DotMap | 0.2
quick_map_services | 0.21.2
ntv2_transformations | 0.20
layer_grid_view | 0.1
pstimeseries | 1.1.1
processing_saga_nextgen | 1.0.0
profile-manager | 0.31
densityanalysis | 2025.4.19
postgis_geoprocessing | 0.9
downloadgeostatportugal | 0.2
Mergin | 2025.1.1
processing | 2.12.99
grassprovider | 2.12.99
db_manager | 0.1.20
MetaSearch | 0.3.6

Libraries
Qt version
5.15.2
Python version
3.9.5
GDAL/OGR version
3.3.2
PROJ version
8.1.1
EPSG Registry database version
v10.028 (2021-07-07)
GEOS version
3.9.1-CAPI-1.14.2
SQLite version
3.35.2
PDAL version
2.3.0
PostgreSQL client version
unknown
SpatiaLite version
5.0.1
QWT version
6.1.6
QScintilla2 version
2.11.5
OS version
macOS 15.5

Active Python plugins
DotMap
0.2
quick_map_services
0.21.2
ntv2_transformations
0.20
layer_grid_view
0.1
pstimeseries
1.1.1
processing_saga_nextgen
1.0.0
profile-manager
0.31
densityanalysis
2025.4.19
postgis_geoprocessing
0.9
downloadgeostatportugal
0.2
Mergin
2025.1.1
processing
2.12.99
grassprovider
2.12.99
db_manager
0.1.20
MetaSearch
0.3.6

[tomasMizera]

Hi @rphenriques, thank you for letting us know, we will investigate the issue further

[volcan01010]

We have seen a similar error:

Traceback (most recent call last):

  File "C:\Users/jostev/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\Mergin\sync_dialog.py", line 223, in push_timer_tick
    push_project_finalize(self.job)

  File "C:\Users/jostev/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\Mergin\mergin\client_push.py", line 268, in push_project_finalize
    resp = job.mc.post("/v1/project/push/finish/%s" % job.transaction_id)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

  File "C:\Users/jostev/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\Mergin\mergin\client.py", line 255, in post
    return self._do_request(request)
           ^^^^^^^^^^^^^^^^^^^^^^^^^

  File "C:\Users/jostev/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\Mergin\mergin\client.py", line 198, in wrapper
    return f(self, *args)
           ^^^^^^^^^^^^^^

  File "C:\Users/jostev/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\Mergin\mergin\client.py", line 211, in _do_request
    server_response = json.load(e)
                      ^^^^^^^^^^^^

  File "C:\PROGRA~1\QGIS34~2.0\apps\Python312\Lib\json\__init__.py", line 293, in load
    return loads(fp.read(),
           ^^^^^^^^^^^^^^^^

  File "C:\PROGRA~1\QGIS34~2.0\apps\Python312\Lib\json\__init__.py", line 346, in loads
    return _default_decoder.decode(s)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^

  File "C:\PROGRA~1\QGIS34~2.0\apps\Python312\Lib\json\decoder.py", line 338, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

  File "C:\PROGRA~1\QGIS34~2.0\apps\Python312\Lib\json\decoder.py", line 356, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None

json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

QGIS version	3.44.0-Solothurn
QGIS code revision	5d9ba037df1
Libraries
Qt version	5.15.13
Python version	3.12.11
GDAL version	3.11.0 — Eganville
PROJ version	9.6.2
EPSG Registry database version	v12.013 (2025-05-26)
GEOS version	3.13.1-CAPI-1.19.2
SQLite version	3.46.1
PDAL version	2.9.0
PostgreSQL client version	17.3
SpatiaLite version	5.1.0
QWT version	6.3.0
QScintilla2 version	2.14.1
OS version	Windows 11 Version 2009
Active Python plugins
Mergin	2025.2
plugin_reloader	0.18

[volcan01010]

The issue occurred when we tried to sync a project folder that contained many photo files (e.g. 2 Gb worth). Adding the photos in batches and uploading them all over 4 separate sync operations allowed the synchronisation to work.

Perhaps there is some kind of timeout on the push. The error happens after the progress bar has reached 100%, suggesting the it might be when the server is doing some kind of validation on the uploaded files.

#732 seems to relate to the same error message.

[rphenriques]

Hi. Just to add some more info on this.

Just today I tested again with QGIS Plugin: same error.

Then, I tried the python-api-client on the local folder:

• mergin status -> showed correct changes
• mergin push -> same error as QGIS Plugin

Then I ran docker logs -f on the server to see if I could find anything

• mergin push -> worked OK

I have no clue why this happened and probably the fact that I had the docker logs open has nothing to do with it working this time.

[tomasMizera]

Hi all, we're actively working on the JSON decode issues you’ve reported. The fix is scheduled for the release following the next version — thanks for your patience in the meantime!

[tomasMizera]

The fix is implemented and scheduled for the upcoming release