I have a shapefile with line features. One of my lines was causing problems in a python script and in the QGIS interface it appeared as two segments (one long one with a brief gap between two nodes).
I used the calculator with
num_geometries( $geometries) and it showed this entry has two geometries (all the others had one). I imagine this is the problem. Is there any way to fix this and merge them back to a single geometry? Deleting and re-digitizing would be a lot of effort. I didn't see anything in the Validity checker and it didn't complain, but that might be because I messed up a parameter.
The merge tools in QGIS digitizing bar is not relevant. It is for merging multiple features, not multiple gometries in one feature -- it complains I have only one feature selected.