zsh: path handling - remove $HOME reliance & make relative/absolute path logic consistent

[kjkent]

Description

Previously, config.programs.zsh.dotDir prepended strings with $HOME. This caused issues where $HOME is inconsistently resolved in time for the evaluation of the option. The handling of this variable is also inconsistent with how paths are handled elsewhere, including within the same module, where config.programs.zsh.history.path does not mutate the supplied string.

This change prepends config.home.homeDirectory to relative paths, while assigning absolute paths unchanged. Tests for both cases are added.

Closes #5100

Checklist

• Change is backwards compatible.

• Code formatted with ./format.

• Code tested through nix-shell --pure tests -A run.all or nix develop --ignore-environment .#all using Flakes.

• Test cases updated/added. See example.

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Maintainer CC

[teto]

I had dotDir = ".config/zsh"; in my config and I think it generated a ZDOTDIR value of

echo $ZDOTDIR
/home/teto.config/zsh

[kjkent]

@teto thanks for raising this -- looking at the code, yeah, I can see where I missed that. Curiously, it didn't cause the test to fail, which is doubly concerning -- let me made a change and test and I'll push an update 👍

[rycee]

Looks like the CI is a bit unhappy with this 🙂 But perhaps not far off from working?

[kjkent]

@rycee yeah -- apologies for the delay on this; I started, then realised there was more to the fix than I anticipated and life got in the way a bit. I'm actually doing nothing right now so will see if I can get it boxed off :)

[kjkent]

@rycee @teto I believe this is good to go. Thanks for your patience with it.

I've been descriptive in the commit messages, but, in addition to original PR description I found that when setting HISTFILE in .zshrc, $HOME was also prepended to any custom programs.zsh.history.path value, if state version was < 20.03 (newer state versions only work with absolute paths), which wasn't conveyed in the description strings. Additionally, state versions >= 20.03 defaulted to the histfile being placed in the home dir while older versions defaulted to ZDOTDIR, which is (in my own view) more logical -- if settings are left at their defaults, it's the same behavior, but if a user makes the choice to move their .z* out of home, it makes little sense to leave this particular one behind (upstream zsh has no default history location -- it's not enabled by default. distros shipping zsh often set/tweak its defaults via a systemwide zshenv.

The first commit removes all reliance on $HOME which should fix the race condition issues seen, and allows both options to accept relative paths (which are interpreted as relative to home.homeDirectory) and absolute paths. The second commit simplifies the history file path handling + restores the sane, pre-20.03 default location.

If the second commit isn't desired I can revert it, otherwise, it poses a minor breaking change to those who have set a custom ZDOTDIR but not a custom HISTFILE location. I'm unsure of the best way to communicate/mitigate this (via state version logic?), though I'd wager those installs are few -- why go to the effort of moving most .z* files out of ~/, but leave one?

[stale]

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[khaneliman]

Curious if you're still interested in pursuing this? We've had a bit of refactoring since this was made.

[khaneliman]

Rebased on master and resolved all the merge conflicts and fixed some issues that were caught in newer tests.

[andrevmatos]

Just FYI, this broke usecases where users had environment variables in programs.zsh.history.path; e.g. I used to have \${XDG_STATE_HOME:-$HOME/.local/state}/zsh/history in there, but this now adds some ' single quotes plus wrong variable expansion inside, which end up creating a path like /home/user/\'/home/user/.local/state/zsh/history\'
Fix is to use ${config.xdg.stateHome} (or other xdg path) interpolated directly

[gepbird]

Same, after updating with programs.zsh.history.path = "$ZDOTDIR/.zsh_history"; (which now renders to HISTFILE="'/home/gep/$ZDOTDIR/.zsh_history'"), this directory structure gets creates when running zsh:

~/foo ❯ find
.
~/foo ❯ zsh
~/foo ❯ find
.
./'
./'/home
./'/home/gep
./'/home/gep/home
./'/home/gep/home/gep
./'/home/gep/home/gep/.config
./'/home/gep/home/gep/.config/zsh
./'/home/gep/home/gep/.config/zsh/.zsh_history'

I agree with this simpler handling, but some warning, release note or hiding it behind a new stateVersion would be nice.

[khaneliman]

@andrevmatos @gepbird thanks for identifying those issues, created #7561 to handle that better. Would be helpful to test with your previous config to verify it works, as expected.

[lzpreslav]

JFYI a trailing slash in my homeDirectory path caused a zsh initialization failure.

My nix-darwin configuration:

users.users."${currentSystemUser}".home = "/Users/${currentSystemUser}/";

After updating and rebuilding I got this .zshenv file which failed zsh initialization with "job table full or recursion limit exceeded":

❯ cat ~/.zshenv        
source /Users/lzpreslav/.zshenv

Removing the trailing slash from the path fixed the issue.