use user_data_dir rather than user_runtime_dir for view notifications

[jjallaire-aisi]

Resolves #665

It seems as if unlike other directories, user_runtime_dir does not have a fallback if the user don't have the requisite parent directories with permissions. This causes failure modes on devcontainers and other minimally configured systems.

The resolution is to use the user_data_dir instead, which has a ~/.local/share fallback on Linux. VS Code extension is also updated to look for view notification files in both locations to support older and newer versions.

[OlyDSIT]

Looks good, thanks JJ!

[art-dsit]

Resolves #665

It seems as if unlike other directories, user_runtime_dir does not have a fallback if the user don't have the requisite parent directories with permissions. This causes failure modes on devcontainers and other minimally configured systems.

The resolution is to use the user_data_dir instead, which has a ~/.local/share fallback on Linux. VS Code extension is also updated to look for view notification files in both locations to support older and newer versions.

I assume you mean user_data_path, per the code in this PR

There is unfortunate inconsistency in naming between XDG and platformdirs.

https://platformdirs.readthedocs.io/en/latest/api.html

has

user_data_dir - data directory tied to the user
user_data_path - data path tied to the user

XDG has

$XDG_DATA_HOME defines the base directory relative to which user-specific data files should be stored. If $XDG_DATA_HOME is either not set or empty, a default equal to $HOME/.local/share should be used.

$XDG_DATA_DIRS defines the preference-ordered set of base directories to search for data files in addition to the $XDG_DATA_HOME base directory. The directories in $XDG_DATA_DIRS should be separated with a colon ':'.

If $XDG_DATA_DIRS is either not set or empty, a value equal to /usr/local/share/:/usr/share/ should be used.

Assuming XDG_DATA_DIRS = user_data_dir, we wouldn't want to use that, since it looks like it would be read-only

If XDG_DATA_HOME = user_data_dir, then we are good to use user_data_dir.

If the upstream bug is fixed, will we revert this to simplify things?

[jjallaire-aisi]

The _dir vs. _path distinction is just one returns a string and one returns a Path

XDG_DATA_DIRS is a fallback list of other root directories to search within (in addition to .local).

I don't think I'll revert if the upstream bug if fixed b/c it will make us depend on a super recent version of platformdirs (which could possibly cause problems for other dependency resolution). runtime_dir is a super obscure variation (again, MacOS and Windows don't even have it) so I think a poor choice in the first place.