IMO if the new Python lexer is far off at all, it might be good to squelch that warning as it is just noise in the context of someone typing a necessarily - at times - broken source file.

Hopefully not far - I believe #1160 is ready to be merged and then the new Python parser can be just copied with minimal changes.

Upstream ctags also reports line number in the warning so it's more descriptive (should get backported to Geany). Null tag names shouldn't be generated no matter what the user has typed and this message helps to detect an error in the parser which would otherwise be undetected.