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home-manager/modules/lib-bash/activation-init.sh
Robert Helgesson f69816489d
home-manager: handle missing per-user profiles directory
Specifically, if the global per-user profiles path do not exist and we
cannot create it during the activation, then place our profile in the
Home Manager data directory. We prefer to use the global location,
though, since it makes it visible to `nix-collect-garbage`.

This is intended to improve compatibility with Nix version 2.14 and
later, which no longer creates the per-user directories.

Also, use the Home Manager data directory to manage the gcroot for the
current generation. It does not have to sit in the global per-user
gcroots directory since it should never be eligible for GC.
2023-03-07 23:53:06 +01:00

131 lines
4.7 KiB
Bash

# Moves the existing profile from /nix to ~ to match changed behavior in Nix
# 2.14. See https://github.com/NixOS/nix/pull/5226.
#
# Note, this function is intentionally unused for now. There remains a few open
# questions about backwards compatibility and support from
# `nix-collect-garbage`.
function migrateProfile() {
declare -r stateHome="${XDG_STATE_HOME:-$HOME/.local/state}"
declare -r hmStateDir="$stateHome/home-manager"
declare -r nixStateDir="${NIX_STATE_DIR:-/nix/var/nix}"
declare -r newProfilesDir="$hmStateDir/profiles"
declare -r oldProfilesDir="$nixStateDir/profiles/per-user/$USER"
if [[ ! -d $newProfilesDir ]]; then
_i 'Migrating profiles from %s to %s' "$oldProfilesDir" "$newProfilesDir"
mkdir -p "$newProfilesDir"
for p in "$oldProfilesDir"/home-manager-*; do
declare -r name="${p##*/}"
nix-store --realise "$p" --add-root "$newProfilesDir/$name" > /dev/null
done
cp -P "$oldProfilesDir/home-manager" "$newProfilesDir"
fi
rm "$oldProfilesDir"/home-manager-*
}
function setupVars() {
declare -r nixStateDir="${NIX_STATE_DIR:-/nix/var/nix}"
declare -r globalProfilesDir="$nixStateDir/profiles/per-user/$USER"
declare -r globalGcrootsDir="$nixStateDir/gcroots/per-user/$USER"
declare -r stateHome="${XDG_STATE_HOME:-$HOME/.local/state}"
declare -r hmStateDir="$stateHome/home-manager"
declare -r hmGcrootsDir="$hmStateDir/gcroots"
# If the global profiles path exists or we can create it, then place the HM
# profile there. Otherwise place it in the HM data directory. We prefer to
# use the global location since it makes it visible to
# `nix-collect-garbage`.
#
# In the future we may perform a one-shot migration to the new location.
#
# shellcheck disable=2174
if [[ -d "$globalProfilesDir" ]] || mkdir -m 0755 -p "$globalProfilesDir"; then
declare -r hmProfilesDir="$globalProfilesDir"
else
declare -r hmProfilesDir="$hmStateDir/profiles"
mkdir -m 0755 -p "$hmProfilesDir"
fi
declare -gr genProfilePath="$hmProfilesDir/home-manager"
declare -gr newGenPath="@GENERATION_DIR@";
declare -gr newGenGcPath="$hmGcrootsDir/current-home"
declare -gr legacyGenGcPath="$globalGcrootsDir/current-home"
declare greatestGenNum
greatestGenNum=$( \
nix-env --list-generations --profile "$genProfilePath" \
| tail -1 \
| sed -E 's/ *([[:digit:]]+) .*/\1/')
if [[ -n $greatestGenNum ]] ; then
declare -gr oldGenNum=$greatestGenNum
declare -gr newGenNum=$((oldGenNum + 1))
else
declare -gr newGenNum=1
fi
if [[ -e $genProfilePath ]] ; then
declare -g oldGenPath
oldGenPath="$(readlink -e "$genProfilePath")"
fi
$VERBOSE_RUN _i "Sanity checking oldGenNum and oldGenPath"
if [[ -v oldGenNum && ! -v oldGenPath
|| ! -v oldGenNum && -v oldGenPath ]]; then
_i $'The previous generation number and path are in conflict! These\nmust be either both empty or both set but are now set to\n\n \'%s\' and \'%s\'\n\nIf you don\'t mind losing previous profile generations then\nthe easiest solution is probably to run\n\n rm %s/home-manager*\n rm %s/current-home\n\nand trying home-manager switch again. Good luck!' \
"${oldGenNum:-}" "${oldGenPath:-}" \
"$hmProfilesDir" "$hmGcrootsDir"
exit 1
fi
}
if [[ -v VERBOSE ]]; then
export VERBOSE_ECHO=echo
export VERBOSE_ARG="--verbose"
export VERBOSE_RUN=""
else
export VERBOSE_ECHO=true
export VERBOSE_ARG=""
export VERBOSE_RUN=true
fi
_i "Starting Home Manager activation"
# Verify that we can connect to the Nix store and/or daemon. This will
# also create the necessary directories in profiles and gcroots.
$VERBOSE_RUN _i "Sanity checking Nix"
nix-build --expr '{}' --no-out-link
setupVars
if [[ -v DRY_RUN ]] ; then
_i "This is a dry run"
export DRY_RUN_CMD=echo
export DRY_RUN_NULL=/dev/stdout
else
$VERBOSE_RUN _i "This is a live run"
export DRY_RUN_CMD=""
export DRY_RUN_NULL=/dev/null
fi
if [[ -v VERBOSE ]]; then
_i 'Using Nix version: %s' "$(nix-env --version)"
fi
$VERBOSE_RUN _i "Activation variables:"
if [[ -v oldGenNum ]] ; then
$VERBOSE_ECHO " oldGenNum=$oldGenNum"
$VERBOSE_ECHO " oldGenPath=$oldGenPath"
else
$VERBOSE_ECHO " oldGenNum undefined (first run?)"
$VERBOSE_ECHO " oldGenPath undefined (first run?)"
fi
$VERBOSE_ECHO " newGenPath=$newGenPath"
$VERBOSE_ECHO " newGenNum=$newGenNum"
$VERBOSE_ECHO " genProfilePath=$genProfilePath"
$VERBOSE_ECHO " newGenGcPath=$newGenGcPath"
$VERBOSE_ECHO " legacyGenGcPath=$legacyGenGcPath"