upgrade-nix: resolve profile symlinks

The profile present in PATH is not necessarily the actual profile
location. User profiles are generally added as $HOME/.nix-profile
in which case the indirect profile link needs to be resolved first.

/home/user/.nix-profile -> /nix/var/nix/profiles/per-user/user/profile
/nix/var/nix/profiles/per-user/user/profile -> profile-15-link
/nix/var/nix/profiles/per-user/user/profile-14-link -> /nix/store/hyi4kkjh3bwi2z3wfljrkfymz9904h62-user-environment
/nix/var/nix/profiles/per-user/user/profile-15-link -> /nix/store/6njpl3qvihz46vj911pwx7hfcvwhifl9-user-environment

To upgrade nix here we want /nix/var/nix/profiles/per-user/user/profile-16-link
instead of /home/user/.nix-profile-1-link. The latter is not a gcroot
and would be garbage collected, resulting in a broken profile.

Fixes #2175
This commit is contained in:
Daiderd Jordan 2018-08-25 20:33:01 +02:00
parent 414397759a
commit d85bb4814f
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@ -103,11 +103,18 @@ struct CmdUpgradeNix : MixDryRun, StoreCommand
if (hasPrefix(where, "/run/current-system"))
throw Error("Nix on NixOS must be upgraded via 'nixos-rebuild'");
Path profileDir;
Path userEnv;
Path profileDir = dirOf(where);
// Resolve profile to /nix/var/nix/profiles/<name> link.
while (baseNameOf(dirOf(canonPath(profileDir))) != "profiles")
profileDir = readLink(profileDir);
printInfo("found profile '%s'", profileDir);
Path userEnv = canonPath(profileDir, true);
if (baseNameOf(where) != "bin" ||
!hasSuffix(userEnv = canonPath(profileDir = dirOf(where), true), "user-environment"))
!hasSuffix(userEnv, "user-environment"))
throw Error("directory '%s' does not appear to be part of a Nix profile", where);
if (!store->isValidPath(userEnv))