[QGIS-Developer] createvectorTable error: Could not retrieve driver for connection

[Richard Duivenvoorde]

Hi Raymond,

I've updated your test script a little:

gpkg_fn = '/tmp/test.gpkg'
try:
     print(QgsProviderRegistry.instance().providerList())
     md = QgsProviderRegistry.instance().providerMetadata('ogr')
     print(f'md = {md}')
     conn = md.createConnection(gpkg_fn, {})
     print(f'conn = {conn}')
     fields = QgsFields()
     fields.append(QgsField('key', QVariant.String))
     fields.append(QgsField('value', QVariant.String))
     conn.createVectorTable('', 'test', fields, QgsWkbTypes.NoGeometry, QgsCoordinateReferenceSystem(), True, {})
except Exception as e:
     print(f'ERROR: {e}')

As said: in my freshly compiled master, this fails to run with 'Could not retrieve driver for connection'
It also fails on my 3.28.0 version I have in a Windows VM.

It DOES print the 'ogr' driver in the providerList() though.

Strange behaviour: after starting (the older compiled) Qgis 3.26 on the same Linux system (in 3.26 the script always seems to work...) QGIS master ALSO works!!!

So I thought it had something todo with loading different provider registries or so?
Maybe master not having something but after starting 3.26 it was there?
Or is it loading (different) gdal/ogr libs order?
Did something change there?

Looking that the createConnection docs:
https://qgis.org/pyqgis/master/core/QgsConnectionRegistry.html#qgis.core.QgsConnectionRegistry.createConnection
I thought to see that your 'id' was only the filename, but adding ogr:// in front of it does not even work...
So not sure if that createConnection doc is old, or if I'm looking in the wrong createConnection...

Anybody can


>>
On 12/2/22 12:30, Raymond Nijssen via QGIS-Developer wrote:
> No one having a clue? Should I create an issue?
> 
> Raymond
> 
> 
> On 30-11-2022 18:08, Raymond Nijssen via QGIS-Developer wrote:
>> Hi developers,
>>
>> Recently some users of my plugin started getting errors in the code that creates a .gpkg file with a table. I wrote a piece of test code:
>>
>> gpkg_fn = '/home/raymond/tmp/test.gpkg'
>> md = QgsProviderRegistry.instance().providerMetadata('ogr')
>> conn = md.createConnection(gpkg_fn, {})
>> fields = QgsFields()
>> fields.append(QgsField('key', QVariant.String))
>> fields.append(QgsField('value', QVariant.String))
>> conn.createVectorTable('', 'test', fields, QgsWkbTypes.NoGeometry, QgsCoordinateReferenceSystem(), True, {})
>>
>>
>> That last line *sometimes* results in this error:
>>
>> _core.QgsProviderConnectionException: Could not retrieve driver for connection
>>
>>
>>
>> I cannot reproduce the error on my laptop (Linux), but Richard tried a few QGIS versions in both Windows and Linux and *sometimes* got the error and sometimes not. Even in the same application, the error disappeared after running another version of QGIS simultaneously... :/
>>
>> No clue if this error is GDAL or Qt or whatever related, pretty puzzling for me. Hope anyone can help!
>>
>> Kind regards,
>> Raymond
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