saveStyleToDatabase() bug when saving more than one layer to a GPKG

[djes]

Describe the bug
For a plugin, I need a way to save my layers in a geopackage with their own style, exactly like the "Package" Tool.
The problem arises when two or more layers are saved. In the destination gpkg, the layer_styles table contains one row by layer, the styleName field is OK but the f_table_name field contains another layer name. I'm almost sure that the bug is in the saveStyleToDatabase() function. I've tried everything, almost reproducing the Package tool function

How to Reproduce
Create two layers with their own style named test and test2 (or download this geopackage http://djes.free.fr/qgis/test.gpkg). Adjust the script to the layers name and destination geopackage. Launch the script for the first layer, destination file is OK. Adjust for the second layer : the style is not correctly saved.

QGIS and OS versions
3.16.5 and 3.18.1 / Windows 10

Additional context
Simplified code (or download it on http://djes.free.fr/qgis/saveLayerWithStyle.py)

layer_name = 'test' #change me
gpkg_name = 'c:\\temp\\mytest.gpkg' #output, change me if needed

#- First, saves the layer
src_layer = QgsProject.instance().mapLayersByName(layer_name)[0]
options = QgsVectorFileWriter.SaveVectorOptions()
options.actionOnExistingFile = QgsVectorFileWriter.CreateOrOverwriteLayer
options.layerName = layer_name
#options.SymbologyExport = QgsVectorFileWriter.FeatureSymbology
#options.driverName = "GPKG"
error = QgsVectorFileWriter.writeAsVectorFormatV2(src_layer, gpkg_name, QgsProject.instance().transformContext(), options)

if error[0] == QgsVectorFileWriter.ErrCreateDataSource:
    print("Create mode")
    options.actionOnExistingFile = QgsVectorFileWriter.CreateOrOverwriteFile #Create mode
    error = QgsVectorFileWriter.writeAsVectorFormatV2(src_layer, gpkg_name, QgsProject.instance().transformContext(), options)
del options
if error[0] == QgsVectorFileWriter.NoError:
    print('Layer "' + layer_name + '" saved in "' + gpkg_name + '"')        
else:
    print(error)
    raise Exception('Failed to save layer')

#- Second, saves the style
#- Load just saved layer
dst_layer = QgsVectorLayer(gpkg_name, layer_name)
if not dst_layer.isValid():
    raise Exception('Failed to load layer')
#print(dst_layer)

myDocument = QDomDocument('qgis')
src_layer.exportNamedStyle(myDocument)
#print(myDocument.toString())
success, message = dst_layer.importNamedStyle(myDocument)
dst_layer.saveStyleToDatabase(layer_name, '', True, '')
QgsProject.instance().removeMapLayer(dst_layer)
del src_layer
del dst_layer
del myDocument

[elpaso]

I wrote a test and I cannot reproduce:

    def testSaveStyle(self):

        tmp_dir = QTemporaryDir()
        tmpfile = os.path.join(tmp_dir.path(), 'testSaveStyle.gpkg')
        ds = ogr.GetDriverByName('GPKG').CreateDataSource(tmpfile)
        lyr = ds.CreateLayer('test', geom_type=ogr.wkbPoint)
        f = ogr.Feature(lyr.GetLayerDefn())
        f.SetGeometry(ogr.CreateGeometryFromWkt('POINT(0 0)'))
        lyr.CreateFeature(f)
        f = ogr.Feature(lyr.GetLayerDefn())
        f.SetGeometry(ogr.CreateGeometryFromWkt('POINT(1 1)'))
        lyr.CreateFeature(f)
        del (lyr)

        lyr = ds.CreateLayer('test2', geom_type=ogr.wkbPoint)
        f = ogr.Feature(lyr.GetLayerDefn())
        f.SetGeometry(ogr.CreateGeometryFromWkt('POINT(0 0)'))
        lyr.CreateFeature(f)
        f = ogr.Feature(lyr.GetLayerDefn())
        f.SetGeometry(ogr.CreateGeometryFromWkt('POINT(1 1)'))
        lyr.CreateFeature(f)
        del(lyr)

        vl1 = QgsVectorLayer(f'{tmpfile}|layername=test'.format(tmpfile), 'test', 'ogr')
        self.assertTrue(vl1.isValid())
        myDocument = QDomDocument('qgis')
        vl1.exportNamedStyle(myDocument)
        success, message = vl1.importNamedStyle(myDocument)
        self.assertTrue(success, message)
        vl1.saveStyleToDatabase(vl1.name(), '', True, '')

        vl2 = QgsVectorLayer(f'{tmpfile}|layername=test2'.format(tmpfile), 'test2', 'ogr')
        self.assertTrue(vl2.isValid())
        myDocument = QDomDocument('qgis')
        vl2.exportNamedStyle(myDocument)
        success, message = vl2.importNamedStyle(myDocument)
        self.assertTrue(success, message)
        vl2.saveStyleToDatabase(vl2.name(), '', True, '')

        md = QgsProviderRegistry.instance().providerMetadata('ogr')
        conn = md.createConnection(tmpfile, {})
        self.assertEqual(conn.executeSql('SELECT f_table_name FROM layer_styles'), [['test'], ['test2']])

[djes]

@elpaso Thank you for digging around ! It works with your example. The syntax I was using for the QgsVectorLayer() function was giving this bad result (even if it seems to work for almost everything).

By modifying my code
dst_layer = QgsVectorLayer(gpkg_name, layer_name)
with
dst_layer = QgsVectorLayer(f'{gpkg_name}|layername={layer_name}', layer_name, 'ogr')

It works like it should. It seems a bit odd anyway to have to repeat the layer name twice but it's alright for me.

Thank you again !

[gioman]

It works like it should. It seems a bit odd anyway to have to repeat the layer name twice but it's alright for me.

@djes closing?

[djes]

It works like it should. It seems a bit odd anyway to have to repeat the layer name twice but it's alright for me.

@djes closing?

In a perfect world, I think one of the QGIS function should be corrected to use the correct layer name. But we're not in a perfect world ;)
For me, you can close.

[gioman]

In a perfect world, I think one of the QGIS function should be corrected to use the correct layer name. But we're not in a perfect world ;)

@djes feature request?

[djes]

Yes, or documentation clarification with a good example. Geopackage and styles are so useful that we need something solid.