The GPX rendering code checks the count of routes found in a GPX file, and only creates a route layer if the count is non-zero.
There are GPX files that only contain an empty tag. This is counted as a valid, though empty, route by the Python gpxparse library, but leads to a
Cannot determine extent for layer 'routes'
error being thrown by the OGR plugin.
So the code that determines whether the route layer should be enabled for a given GPX file should check for the count of non-empty routes being non-zero, not just for the total route count.
The GPX rendering code checks the count of routes found in a GPX file, and only creates a route layer if the count is non-zero.
There are GPX files that only contain an empty
Cannot determine extent for layer 'routes'error being thrown by the OGR plugin.
So the code that determines whether the route layer should be enabled for a given GPX file should check for the count of non-empty routes being non-zero, not just for the total route count.