Avoid crash when styles aren't available yet

[zvonler-sfw]

Fixes a frequent but intermittent crash when using the dialogs in an emulated virtual machine. Discussion here #96

Please include this fix in a v0.6.1 release so that it can be picked up by systems still on Python 3.9.

[davep]

Please include this fix in a v0.6.1 release so that it can be picked up by systems still on Python 3.9.

I'm afraid I only maintain a "latest" release, not earlier releases. Also Python 3.9 has been EOL for about six months at this point and I prefer to only maintain for Python versions that are still supported.

[zvonler-sfw]

Understood. In case anyone else runs into the problem, I'll include here how I'm monkey patching the library in my application as a workaround for Python 3.9:

from textual_fspicker.parts.directory_navigation import DirectoryNavigation, DirectoryEntryStyling
from rich.style import Style

def get_styles_checked(self) -> DirectoryEntryStyling:
    try:
        return DirectoryEntryStyling(
            self.get_component_rich_style("directory-navigation--hidden"),
            self.get_component_rich_style("directory-navigation--name", partial=True),
            self.get_component_rich_style("directory-navigation--size", partial=True),
            self.get_component_rich_style("directory-navigation--time", partial=True),
        )
    except KeyError:
        return DirectoryEntryStyling(Style(), Style(), Style(), Style())

DirectoryNavigation._styles = property(get_styles_checked)