libguestfs was not setting an error during some appliance launch failures. Python bindings assume that the error string is not NULL, and would segfault if it was NULL.
Python programs could segfault when 'g.launch()' was called under some circumstances.
libguestfs now sets the error string on all failure paths in launch, and the Python bindings have been fixed not to segfault.
Python programs won't segfault when calling 'g.launch()'