Clean up a few things related to profiles (#8526)

- Greatly expand API docs

- Clean up code in misc ways

  - Instead of a complicated single loop on generations, do different
    operations in successive subsequent steps.

  - Avoid `ref` in one place where `&` is fine

  - Just return path instead of mutating an argument in `makeName`

Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>

2 files changed, 5 insertions, 4 deletions

diff --git a/src/nix-env/nix-env.cc b/src/nix-env/nix-env.cc
index 5e94f2d14..91b073b49 100644
--- a/src/nix-env/nix-env.cc
+++ b/src/nix-env/nix-env.cc
@@ -772,7 +772,7 @@ static void opSet(Globals & globals, Strings opFlags, Strings opArgs)
 
     debug("switching to new user environment");
     Path generation = createGeneration(
-        ref<LocalFSStore>(store2),
+        *store2,
         globals.profile,
         drv.queryOutPath());
     switchLink(globals.profile, generation);
@@ -1356,13 +1356,14 @@ static void opDeleteGenerations(Globals & globals, Strings opFlags, Strings opAr
     if (opArgs.size() == 1 && opArgs.front() == "old") {
         deleteOldGenerations(globals.profile, globals.dryRun);
     } else if (opArgs.size() == 1 && opArgs.front().find('d') != std::string::npos) {
-        deleteGenerationsOlderThan(globals.profile, opArgs.front(), globals.dryRun);
+        auto t = parseOlderThanTimeSpec(opArgs.front());
+        deleteGenerationsOlderThan(globals.profile, t, globals.dryRun);
     } else if (opArgs.size() == 1 && opArgs.front().find('+') != std::string::npos) {
         if (opArgs.front().size() < 2)
             throw Error("invalid number of generations '%1%'", opArgs.front());
         auto str_max = opArgs.front().substr(1);
         auto max = string2Int<GenerationNumber>(str_max);
-        if (!max || *max == 0)
+        if (!max)
             throw Error("invalid number of generations to keep '%1%'", opArgs.front());
         deleteGenerationsGreaterThan(globals.profile, *max, globals.dryRun);
     } else {
diff --git a/src/nix-env/user-env.cc b/src/nix-env/user-env.cc
index 9e916abc4..d12d70f33 100644
--- a/src/nix-env/user-env.cc
+++ b/src/nix-env/user-env.cc
@@ -158,7 +158,7 @@ bool createUserEnv(EvalState & state, DrvInfos & elems,
         }
 
         debug("switching to new user environment");
-        Path generation = createGeneration(ref<LocalFSStore>(store2), profile, topLevelOut);
+        Path generation = createGeneration(*store2, profile, topLevelOut);
         switchLink(profile, generation);
     }