[RRFC] Respect platform specific directories for config, data, cache, etc.

[natestemen]

This is a follow on since npm/cli#654 was closed.

Motivation ("The Why")

When using npm, it should not leave files/directories in the users' home directory if known environment variables are set, e.g. XDG_CONFIG_HOME.

How

Current Behaviour

npm creates a ~/.npm directory.

Desired Behaviour

npm should create the needed config/cache files/directories with respect to https://wiki.archlinux.org/title/XDG_Base_Directory.

[lousyd]

To clarify, the XDG Base Directory Specification does not require that environment variables be set. For example, it says, "$XDG_CONFIG_HOME defines the base directory relative to which user-specific configuration files should be stored. If $XDG_CONFIG_HOME is either not set or empty, a default equal to $HOME/.config should be used."

While npm could certainly choose to use existence of the environment variable as an indication of whether any particular person wants npm to observe XDG or not, it would not be a reliable signal. There are going to be lots of cases of people who don't set the variables and yet still expect software to "play well with others" by putting files in the XDG-expected locations. The converse situation -- people who really don't want you to observe XDG -- is surely.... rare.

Just follow XDG. Don't require the environment variables be set.

[ljharb]

In my experience maintaining nvm, users who do not set the environment variables but have any concept or expectation of XDG in their minds don't exist. I think only caring about XDG when the env vars are set is a perfectly reasonable approach.

[samhh]

@ljharb I disagree with you.

I care about XDG but only explicitly set them when I either want to use irregular locations or when I need access to them for some other purpose (e.g. ironically handling programs that support specifying the path but are ignorant of XDG). I assume the defaults will be respected per the specification.

A better way of framing it may be:

• Users who care about XDG might or might not have set the variables. They'll expect XDG-compliance by default.
• Users who don't care about XDG won't have set the variables and probably won't care where their data lives.

[ljharb]

The vast majority of users don't care about XDG at all, though. I explicitly and actively want the way things are, and I personally don't like the XDG spec at all. Currently I do that by simply not setting the XDG variables, and thus "almost every tool in existence" does nothing, since virtually every tool also does not respect XDG even when set.

[samhh]

You're absolutely right that the vast majority of users don't care about XDG. Equally I don't think they'd care if it became the default. The most impassioned voices on this issue will I think naturally be those like myself who want support. Do you not think you're going to be in the minority here @ljharb? I may be mistaken.

A lot - not all - of major Linux applications support the spec. Notably the usual reason for lack of support is backwards-compatibility concerns. I think it's a much different story on macOS.

To be clear I'd ideally like support without the need to explicitly opt-in; see here how noisy my shell config has become trying to opt everything in.

[WhyNotHugo]

Prior discussion on the topic has happened here: npm/cli#1451

A few others have voiced support for the issue, and there's also a PR, although in an abandoned state, for anyone willing to pick that up.

FWIW, any user who "does not care" about XDG won't be negatively affected by this. I very much doubt there are many users (if any) that actively want random applications to dump cache data right into their home directories.

[ljharb]

A large part of the js ecosystem describes the locations of npm’s cache folder, as well as a user-level $HOME/.npmrc, and changing these defaults would never be worth the churn.

[samhh]

How many significant tools are there that make these assumptions? In theory if it's just a few then it wouldn't be too hard to update them to support checking two locations, first XDG and then legacy.

[ljharb]

@samhh ive never met a tool that publicized XDG support. I’ve only ever heard of XDG (before these npm issues) because like 3 people in 10 years have requested that nvm support it, which it does only when the env vars are set.

[samhh]

fish references it in its documentation for example.

Which tools are significant and directly access npm files?

[natestemen]

In my view supporting XDG isn't about being able to publicize/advertise the fact that you support XDG, but rather because it makes using a terminal ever so slightly better, and more understandable.

@ljharb I don't understand your considerable pushback here. Would you mind elucidating what it actually is about supporting XDG that you don't like? As of now it seems like you don't want to support it because:

1. you don't believe it's useful to those who don't have the env vars set (which I think we'll agree will be the majority of users)
2. it's not widely supported (as of now, but my understanding is that this is moving towards XDG adoption)
3. you believe very few people care about this

I think the last point is probably true, but that doesn't indicate whether it will be helpful for them or not. I think most people have never heard of XDG to begin with.

[WhyNotHugo]

I'm looking at my dotfiles and see 21 apps that support the basedir spec (including git, neovim and systemd).

Chromium also has support, albeit imperfect and it mixes runtime files with config files (this is more of a bug than refusal to support it).

The only exceptions I see are npm, go, yarn, Firefox (just historical reasons and slow moving) and tools that cannot support it, like ssh and zsh. This last group cannot support the spec, since they're the ones who define environment variables and that'd be a chicken and egg.

That's still 21 supporting apps vs 4 that don't -- none of which refuse to support the standard, just haven't gotten around to it yet.

Honestly, I see no reason to NOT support this standard and keep saving cache files into home directories. I'm still curious why someone would want cache files in their $HOME rather than in the directory specially designated for that. Do you want all cache files in $HOME, or just npm's?

[ljharb]

@natestemen i have no objection to supporting it when the env vars are defined. My pushback is against the following points:

1. Not supporting xdg is never a bug, it’s merely a choice, because xdg isn’t a universal or mandated thing
2. When the env vars are not defined, the current/default/original behavior of a tool should be retained.

I personally prefer, and find it much cleaner, to have my $HOME filled with things from every too., and actively don’t want them hidden away in an obscure directory. Those who disagree can certainly set their XDG vars and ask for tools to support that.

[samhh]

@ljharb Isn't it more reasonable - on the basis of active support for either approach - to suggest that those who want everything in their home directory to just set their XDG vars accordingly?