Constant ValueErrors before EPSG is set

[lvh]

def get_code_from_epsg(epsg_string: StrOrInt) -> int:
    code = str(epsg_string).upper()
    if code.startswith("EPSG:"):
        code = code.replace("EPSG:", "")
    elif code.startswith("USER:"):
        code = code.replace("USER:", "")
    return int(code)

That last line errors when no EPSG is set, because epsg_string will be "" and so will "code". This function gets called from:

    def _get_qgis_crs(self) -> str:
        canvas = self.iface.mapCanvas()
        auth_id: str = canvas.mapSettings().destinationCrs().authid()
        return str(get_code_from_epsg(auth_id))

Because _get_qgis_crs gets called all the time (in _on_timeout, in _handle_mouse_move...) this basically results in constant errors.

I'll try to write a patch.

[lvh]

I'm actually open to suggestions for how to fix it. One is to change the return type to Optional[int] and push the optionality up the stack. Another is to return int(code) if code else 3857, but that might be seen as further reinforcing the dependence on 3857 that I think you've tried to get rid of elsewhere. (That said.... if you want a different EPSG maybe specify one :))