fish config for loading nix in non-nixos

This commit is contained in:
Noah Masur 2022-01-25 12:49:20 -05:00
parent 41eff7f1d8
commit 1604e7ba47

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# Setup Nix
# We need to distinguish between single-user and multi-user installs.
# This is difficult because there's no official way to do this.
# We could look for the presence of /nix/var/nix/daemon-socket/socket but this will fail if the
# daemon hasn't started yet. /nix/var/nix/daemon-socket will exist if the daemon has ever run, but
# I don't think there's any protection against accidentally running `nix-daemon` as a user.
# We also can't just look for /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh because
# older single-user installs used the default profile instead of a per-user profile.
# We can still check for it first, because all multi-user installs should have it, and so if it's
# not present that's a pretty big indicator that this is a single-user install. If it does exist,
# we still need to verify the install type. To that end we'll look for a root owner and sticky bit
# on /nix/store. Multi-user installs set both, single-user installs don't. It's certainly possible
# someone could do a single-user install as root and then manually set the sticky bit but that
# would be extremely unusual.
set -l nix_profile_path /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh
set -l single_user_profile_path ~/.nix-profile/etc/profile.d/nix.sh
if test -e $nix_profile_path
# The path exists. Double-check that this is a multi-user install.
# We can't just check for ~/.nix-profile/… because this may be a single-user install running as
# the wrong user.
# stat is not portable. Splitting the output of ls -nd is reliable on most platforms.
set -l owner (string split -n ' ' (command ls -nd /nix/store 2>/dev/null))[3]
if not test -k /nix/store -a $owner -eq 0
# /nix/store is either not owned by root or not sticky. Assume single-user.
set nix_profile_path $single_user_profile_path
end
else
# The path doesn't exist. Assume single-user
set nix_profile_path $single_user_profile_path
end
if test -e $nix_profile_path
# Source the nix setup script
# We're going to run the regular Nix profile under bash and then print out a few variables
for line in (command env -u BASH_ENV bash -c '. "$0"; for name in PATH "${!NIX_@}"; do printf "%s=%s\0" "$name" "${!name}"; done' $nix_profile_path | string split0)
set -xg (string split -m 1 = $line)
end
# Insert Nix's fish share directories into fish's special variables.
# nixpkgs-installed fish tries to set these up already if NIX_PROFILES is defined, which won't
# be the case when sourcing $__fish_data_dir/share/config.fish normally, but might be for a
# recursive invocation. To guard against that, we'll only insert paths that don't already exit.
# Furthermore, for the vendor_conf.d sourcing, we'll use the pre-existing presence of a path in
# $fish_function_path to determine whether we want to source the relevant vendor_conf.d folder.
# To start, let's locally define NIX_PROFILES if it doesn't already exist.
set -al NIX_PROFILES
if test (count $NIX_PROFILES) -eq 0
set -a NIX_PROFILES $HOME/.nix-profile
end
# Replicate the logic from nixpkgs version of $__fish_data_dir/__fish_build_paths.fish.
set -l __nix_profile_paths (string split ' ' -- $NIX_PROFILES)[-1..1]
set -l __extra_completionsdir \
$__nix_profile_paths/etc/fish/completions \
$__nix_profile_paths/share/fish/vendor_completions.d
set -l __extra_functionsdir \
$__nix_profile_paths/etc/fish/functions \
$__nix_profile_paths/share/fish/vendor_functions.d
set -l __extra_confdir \
$__nix_profile_paths/etc/fish/conf.d \
$__nix_profile_paths/share/fish/vendor_conf.d
### Configure fish_function_path ###
# Remove any of our extra paths that may already exist.
# Record the equivalent __extra_confdir path for any function path that exists.
set -l existing_conf_paths
for path in $__extra_functionsdir
if set -l idx (contains --index -- $path $fish_function_path)
set -e fish_function_path[$idx]
set -a existing_conf_paths $__extra_confdir[(contains --index -- $path $__extra_functionsdir)]
end
end
# Insert the paths before $__fish_data_dir.
if set -l idx (contains --index -- $__fish_data_dir/functions $fish_function_path)
# Fish has no way to simply insert into the middle of an array.
set -l new_path $fish_function_path[1..$idx]
set -e new_path[$idx]
set -a new_path $__extra_functionsdir
set fish_function_path $new_path $fish_function_path[$idx..-1]
else
set -a fish_function_path $__extra_functionsdir
end
### Configure fish_complete_path ###
# Remove any of our extra paths that may already exist.
for path in $__extra_completionsdir
if set -l idx (contains --index -- $path $fish_complete_path)
set -e fish_complete_path[$idx]
end
end
# Insert the paths before $__fish_data_dir.
if set -l idx (contains --index -- $__fish_data_dir/completions $fish_complete_path)
set -l new_path $fish_complete_path[1..$idx]
set -e new_path[$idx]
set -a new_path $__extra_completionsdir
set fish_complete_path $new_path $fish_complete_path[$idx..-1]
else
set -a fish_complete_path $__extra_completionsdir
end
### Source conf directories ###
# The built-in directories were already sourced during shell initialization.
# Any __extra_confdir that came from $__fish_data_dir/__fish_build_paths.fish was also sourced.
# As explained above, we're using the presence of pre-existing paths in $fish_function_path as a
# signal that the corresponding conf dir has also already been sourced.
# In order to simulate this, we'll run through the same algorithm as found in
# $__fish_data_dir/config.fish except we'll avoid sourcing the file if it comes from an
# already-sourced location.
# Caveats:
# * Files will be sourced in a different order than we'd ideally do (because we're coming in
# after the fact to source them).
# * If there are existing extra conf paths, files in them may have been sourced that should have
# been suppressed by paths we're inserting in front.
# * Similarly any files in $__fish_data_dir/vendor_conf.d that should have been suppressed won't
# have been.
set -l sourcelist
for file in $__fish_config_dir/conf.d/*.fish $__fish_sysconf_dir/conf.d/*.fish
# We know these paths were sourced already. Just record them.
set -l basename (string replace -r '^.*/' '' -- $file)
contains -- $basename $sourcelist
or set -a sourcelist $basename
end
for root in $__extra_confdir
for file in $root/*.fish
set -l basename (string replace -r '^.*/' '' -- $file)
contains -- $basename $sourcelist
and continue
set -a sourcelist $basename
contains -- $root $existing_conf_paths
and continue # this is a pre-existing path, it will have been sourced already
[ -f $file -a -r $file ]
and source $file
end
end
end