Setting/changing geometry type for .TAB file in QGIS

Question

I have a .TAB-file with MultiLines. When I load it to QGIS, in layer properties it says Geometry: Line (LineString) which is wrong. When I try to do some operations with geometries (like snap to layer) QGIS breaks all geometries into single lines.

I've tried to:

1. Save the layer with the "force multi-type" option enabled
2. Create a memory layer with multi-type geometry and save it as .TAB
3. Create a .TAB with one multiline geometry feature

None of the options worked.

My final goal is just to save processed multi-type geometries back to .TAB file without splitting into single-type.

Answer 1

It's not an answer to my question. But @KVO asked for PyQGIS solution. Here is mine:

for layer in QgsProject.instance().mapLayers().values():
    source = layer.source()
    ext=source.split('|')[0].rpartition('.')[-1]
    if ext.lower() == 'tab':
        if layer.geometryType() == 2:
            newSource=source.replace('geometrytype=Polygon','geometrytype=MultiPolygon')
        elif layer.geometryType() == 1:
            newSource=source.replace('geometrytype=LineString','geometrytype=MultiLineString')
        layer.setDataSource(newSource,layer.name(),'ogr')
        layer.reload()
        layer.triggerRepaint()