XDG compliance

[Conaclos]

Hi :)

I noted that Yarn doesn't fit the XDG basedir specification.
It could be nice to support it.

What is the current behavior?

Currently Yarn creates its own data / cache / config directories:

• $HOME/.yarn
• $HOME/.yarn-cache
• $HOME/.yarn-config

What is the expected behavior?

Next the desired replacement (or fallback) of each directory.

• $HOME/.yarn: ${XDG_DATA_HOME:-$HOME/.local/share}/yarn
• $HOME/.yarn-cache: ${XDG_CACHE_HOME:-$HOME/.cache}/yarn
• $HOME/.yarn-config: ${XDG_CONFIG_HOME:-$HOME/.config}/yarn

OS: Linux

[jleclanche]

@kevinburke @bestander So there was an attempt at fixing this back in April, but it got abandoned.

Any chance we could get a proper plan of what needs to be done to fix this?

Qt has an excellent cross-platform reference implementation of "standard paths" in QStandardPaths: https://doc.qt.io/qt-5/qstandardpaths.html - I don't know if this exists for node, but I know it's come up in other places as well (eg. serverless/serverless#4602)

[bestander]

If someone opens a new PR based on #3674 ping me I'll merge it

[severen]

This seems to be partially fixed by #5336, at least on Yarn 1.9.4. However there's still $HOME/.yarn (which appears to only contain the bin folder) and $HOME/.yarnrc, despite there also being $XDG_CONFIG_HOME/yarn (with the contents debatably being configuration), $XDG_DATA_HOME/yarn (which seems to overlap with $XDG_CONFIG_HOME/yarn...?), and $XDG_CACHE_HOME/yarn (which seems to be the only one that is properly and correctly used). This is even worse than not supporting it at all, as it's now just inconsistent and confusing.

It would be very nice if everything would be moved to follow the XDG spec. Ideally .yarnrc would be $XDG_CONFIG_HOME/yarn/config. As for $HOME/.yarn/bin, that is a bit more complicated, as the spec doesn't define a location for user-installed binaries, although $HOME/.local/bin is commonly used, which lines up with the default for $XDG_DATA_HOME ($HOME/.local/share). Hopefully one day the spec will be amended to include something like $XDG_BIN_HOME. However I believe the best solution for now is to place executables in $XDG_DATA_HOME/yarn/bin and provide an environment variable to customise that location (for example, YARN_BIN_DIR).

I may be able to work on this provided I can find my way around the codebase. Making sure my home directory is completely clean and not littered with a thousand random dotfiles is the dream after all.

[Siilwyn]

Is this free to pick up? I'm thinking of fixing this, I've already done this for other projects like electron-download, js-v8flags, greenkeeper and node-gyp. But I worry about having to be backward compatible, looking at the current logic it can get pretty messy.

Is it possible to make this a major change? Then I would be more than happy to fix this, using env-paths it will be pretty straightforward. @bestander