Fix locating jabref in jabrefHost.py

[michaellass]

shutil.which() returns an str and not a pathlib.Path. Therefore, we need to check if which() actually returns something and if so, we should convert it to a pathlib.Path such that JABREF_PATH is always of the same type.

I stumbled across this while fixing JabRef/JabRef-Browser-Extension#158 for the unofficial Arch Linux JabRef package in the Arch User Repository (AUR): michaellass/AUR#17

• Change in CHANGELOG.md described (if applicable)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked documentation: Is the information available and up to date? If not created an issue at https://github.com/JabRef/user-documentation/issues or, even better, submitted a pull request to the documentation repository.

[michaellass]

Would it make sense to test for shutil.which("JabRef") as well here? To me it seems somehow inconsistent to expect either /opt/jabref/bin/JabRef or lowercase jabref in $PATH.

[Siedlerchr]

Thanks for fixing this!
@LyzardKing can you take a look please?

[LyzardKing]

Looks good! Thanks for pointing out the pathlib issue.
I think we can add the uppercase version as well, just to be on the safe side.

[LyzardKing]

I wonder if setting an if-else chain is easier to read...
Especially if we need to add different paths (I'm thinking of the flatpak now, since I still have to properly figure out that integration...)

Something like:

relpath_path = script_dir / "bin/JabRef"
lowercase_path = shutil.which("jabref")
uppercase_path = shutil.which("JabRef")
if relpath_path.exists():
    JABREF_PATH = relpath_path
elif lowercase_path is not None and os.path.exists(lowercase_path):
    JABREF_PATH = Path(lowercase_path)
elif uppercase_path is not None and os.path.exists(uppercase_path):
    JABREF_PATH = Path(uppercase_path)
else:
    logging.error("Could not determine JABREF_PATH")
    sys.exit(-1)

[michaellass]

I think that's a good idea to avoid the deep nesting. I updated the PR using your suggested code.

[Siedlerchr]

Suggested change

	- We fixed an issue with the python script used by browser plugins that failed to locate JabRef if not installed in its default location.
	- We fixed an issue with the python script used by browser plugins that failed to locate JabRef if not installed in its default location. [#6963](https://github.com/JabRef/jabref/pull/6963/files)

[michaellass]

👍

[Siedlerchr]

Please let us know if this is ready for merge.