Fix error with NVC and the --gui flag

[0dinD]

Fixes #926

#926 (comment) by @umarcor

For reference, in GHDL the Path is converted to str in

vunit/vunit/sim_if/ghdl.py

Line 338 in 1bc4d06

data_file_name = str(Path(script_path) / f"wave.{self._gtkwave_fmt!s}")

Yeah, the GHDL interface does the string conversion earlier:

vunit/vunit/sim_if/ghdl.py

Lines 330 to 340 in fc91e48

	script_path = str(Path(output_path) / self.name)
	if not Path(script_path).exists():
	makedirs(script_path)
	ghdl_e = elaborate_only and config.sim_options.get("ghdl.elab_e", False)
	if self._gtkwave_fmt is not None:
	data_file_name = str(Path(script_path) / f"wave.{self._gtkwave_fmt!s}")
	if Path(data_file_name).exists():
	remove(data_file_name)

But the path is still useful (for checking if the file exists and so on), so the code ends up converting back and forth between Path and str everywhere. Is it not better to wait with the string conversion until a string is required, like what I did in cc5c607?

I could add a commit to refactor the Path handling in the GHDL (or NVC?) interface, if you want it to be more consistent.

[umarcor]

@0dinD, it's ok. I provided the reference to GHDL's implementation for completeness only, to support your point that this change to NVC is correct indeed.

According to your comment/analysis, if you want to make GHDL's implementation cleaner (to reduce the number of changes to/from Path/str), that'd be welcome. Nonetheless, we can have this merged as-is, and deal with that in an upcoming PR.

Thanks for fixing this!