make profile querying logic more consistent (?)

Change-Id: I00a4a8ba7f3a33aa191383f745f5a1395602e938

src/nix-channel/nix-channel.cc

@@ -169,7 +169,7 @@ static int main_nix_channel(int argc, char ** argv)
         nixDefExpr = getNixDefExpr();
 
         // Figure out the name of the channels profile.
-        profile = profilesDir() +  "/channels";
+        profile = defaultChannelsDir();
         createDirs(dirOf(profile));
 
         enum {

src/nix-collect-garbage/nix-collect-garbage.cc

@@ -81,7 +81,13 @@ static int main_nix_collect_garbage(int argc, char * * argv)
 
         if (removeOld) {
             std::set<Path> dirsToClean = {
-                profilesDir(), settings.nixStateDir + "/profiles", dirOf(getDefaultProfile())};
+                // XXX: check
+                profilesDir(),
+                // XXX: refactor
+                settings.nixStateDir + "/profiles",
+                /// XXX: check
+                dirOf(getDefaultProfile()),
+            };
             for (auto & dir : dirsToClean)
                 removeOldGenerations(dir);
         }

src/nix-env/nix-env.cc

@@ -503,7 +503,7 @@ static bool keep(DrvInfo & drv)
 static void installDerivations(Globals & globals,
     const Strings & args, const Path & profile)
 {
-    debug("installing derivations");
+    debug("installing derivations into profile %s", profile);
 
     /* Get the set of user environment elements to be installed. */
     DrvInfos newElems, newElemsTmp;
@@ -554,8 +554,17 @@ static void installDerivations(Globals & globals,
 
         if (globals.dryRun) return;
 
-        if (createUserEnv(*globals.state, allElems,
-                profile, settings.envKeepDerivations, lockToken)) break;
+        bool success = createUserEnv(
+            *globals.state,
+            allElems,
+            profile,
+            settings.envKeepDerivations,
+            lockToken
+        );
+
+        if (success) {
+            break;
+        }
     }
 }
 
@@ -1296,6 +1305,7 @@ static void opSwitchProfile(Globals & globals, Strings opFlags, Strings opArgs)
     if (opArgs.size() != 1)
         throw UsageError("exactly one argument expected");
 
+    // XXX: refactor
     Path profile = absPath(opArgs.front());
     Path profileLink = settings.useXDGBaseDirectories ? createNixStateDir() + "/profile" : getHome() + "/.nix-profile";
 
@@ -1463,8 +1473,10 @@ static int main_nix_env(int argc, char * * argv)
                 op = opQuery;
                 opName = "-query";
             }
-            else if (*arg == "--profile" || *arg == "-p")
+            else if (*arg == "--profile" || *arg == "-p") {
+                // XXX: check
                 globals.profile = absPath(getArg(*arg, arg, end));
+            }
             else if (*arg == "--file" || *arg == "-f")
                 file = getArg(*arg, arg, end);
             else if (*arg == "--switch-profile" || *arg == "-S") {
@@ -1528,11 +1540,15 @@ static int main_nix_env(int argc, char * * argv)
 
         globals.instSource.autoArgs = myArgs.getAutoArgs(*globals.state);
 
-        if (globals.profile == "")
+        if (globals.profile == "") {
+            // XXX: refactor?
             globals.profile = getEnv("NIX_PROFILE").value_or("");
+        }
 
-        if (globals.profile == "")
-            globals.profile = getDefaultProfile();
+        if (globals.profile == "") {
+            // XXX: check
+            globals.profile = ensureDefaultProfile();
+        }
 
         op(globals, std::move(opFlags), std::move(opArgs));
 

src/nix-env/user-env.cc

@@ -20,6 +20,7 @@ bool createUserEnv(EvalState & state, DrvInfos & elems,
     const Path & profile, bool keepDerivations,
     const std::string & lockToken)
 {
+    debug("asked to create a user env %s for %u drvs", profile, elems.size());
     /* Build the components in the user environment, if they don't
        exist already. */
     std::vector<StorePathWithOutputs> drvsToBuild;
@@ -131,10 +132,11 @@ bool createUserEnv(EvalState & state, DrvInfos & elems,
         state.repair ? bmRepair : bmNormal);
 
     /* Switch the current user environment to the output path. */
-    auto store2 = state.store.dynamic_pointer_cast<LocalFSStore>();
+    auto localStore = state.store.dynamic_pointer_cast<LocalFSStore>();
 
-    if (store2) {
+    if (localStore) {
         PathLocks lock;
+        debug("locking profile %s", profile);
         lockProfile(lock, profile);
 
         Path lockTokenCur = optimisticLockProfile(profile);
@@ -144,7 +146,7 @@ bool createUserEnv(EvalState & state, DrvInfos & elems,
         }
 
         debug("switching to new user environment");
-        Path generation = createGeneration(*store2, profile, topLevelOut);
+        Path generation = createGeneration(*localStore, profile, topLevelOut);
         switchLink(profile, generation);
     }