Backport 'nix dev-shell' from the flakes branch

This also adds a '--profile' option to 'nix build' (replacing 'nix-env
--set').

1 files changed, 42 insertions, 78 deletions

diff --git a/src/nix/run.cc b/src/nix/run.cc
index f885c5e49..8e30264c0 100644
--- a/src/nix/run.cc
+++ b/src/nix/run.cc
@@ -8,6 +8,7 @@
 #include "fs-accessor.hh"
 #include "progress-bar.hh"
 #include "affinity.hh"
+#include "eval.hh"
 
 #if __linux__
 #include <sys/mount.h>
@@ -19,11 +20,46 @@ using namespace nix;
 
 std::string chrootHelperName = "__run_in_chroot";
 
-struct CmdRun : InstallablesCommand
+struct RunCommon : virtual Command
+{
+    void runProgram(ref<Store> store,
+        const std::string & program,
+        const Strings & args)
+    {
+        stopProgressBar();
+
+        restoreSignals();
+
+        restoreAffinity();
+
+        /* If this is a diverted store (i.e. its "logical" location
+           (typically /nix/store) differs from its "physical" location
+           (e.g. /home/eelco/nix/store), then run the command in a
+           chroot. For non-root users, this requires running it in new
+           mount and user namespaces. Unfortunately,
+           unshare(CLONE_NEWUSER) doesn't work in a multithreaded
+           program (which "nix" is), so we exec() a single-threaded
+           helper program (chrootHelper() below) to do the work. */
+        auto store2 = store.dynamic_pointer_cast<LocalStore>();
+
+        if (store2 && store->storeDir != store2->realStoreDir) {
+            Strings helperArgs = { chrootHelperName, store->storeDir, store2->realStoreDir, program };
+            for (auto & arg : args) helperArgs.push_back(arg);
+
+            execv(readLink("/proc/self/exe").c_str(), stringsToCharPtrs(helperArgs).data());
+
+            throw SysError("could not execute chroot helper");
+        }
+
+        execvp(program.c_str(), stringsToCharPtrs(args).data());
+
+        throw SysError("unable to execute '%s'", program);
+    }
+};
+
+struct CmdRun : InstallablesCommand, RunCommon, MixEnvironment
 {
     std::vector<std::string> command = { "bash" };
-    StringSet keep, unset;
-    bool ignoreEnvironment = false;
 
     CmdRun()
     {
@@ -37,28 +73,6 @@ struct CmdRun : InstallablesCommand
                 if (ss.empty()) throw UsageError("--command requires at least one argument");
                 command = ss;
             });
-
-        mkFlag()
-            .longName("ignore-environment")
-            .shortName('i')
-            .description("clear the entire environment (except those specified with --keep)")
-            .set(&ignoreEnvironment, true);
-
-        mkFlag()
-            .longName("keep")
-            .shortName('k')
-            .description("keep specified environment variable")
-            .arity(1)
-            .labels({"name"})
-            .handler([&](std::vector<std::string> ss) { keep.insert(ss.front()); });
-
-        mkFlag()
-            .longName("unset")
-            .shortName('u')
-            .description("unset specified environment variable")
-            .arity(1)
-            .labels({"name"})
-            .handler([&](std::vector<std::string> ss) { unset.insert(ss.front()); });
     }
 
     std::string description() override
@@ -94,35 +108,13 @@ struct CmdRun : InstallablesCommand
 
         auto accessor = store->getFSAccessor();
 
-        if (ignoreEnvironment) {
-
-            if (!unset.empty())
-                throw UsageError("--unset does not make sense with --ignore-environment");
-
-            std::map<std::string, std::string> kept;
-            for (auto & var : keep) {
-                auto s = getenv(var.c_str());
-                if (s) kept[var] = s;
-            }
-
-            clearEnv();
-
-            for (auto & var : kept)
-                setenv(var.first.c_str(), var.second.c_str(), 1);
-
-        } else {
-
-            if (!keep.empty())
-                throw UsageError("--keep does not make sense without --ignore-environment");
-
-            for (auto & var : unset)
-                unsetenv(var.c_str());
-        }
 
         std::unordered_set<StorePath> done;
         std::queue<StorePath> todo;
         for (auto & path : outPaths) todo.push(path.clone());
 
+        setEnviron();
+
         auto unixPath = tokenizeString<Strings>(getEnv("PATH").value_or(""), ":");
 
         while (!todo.empty()) {
@@ -142,38 +134,10 @@ struct CmdRun : InstallablesCommand
 
         setenv("PATH", concatStringsSep(":", unixPath).c_str(), 1);
 
-        std::string cmd = *command.begin();
         Strings args;
         for (auto & arg : command) args.push_back(arg);
 
-        stopProgressBar();
-
-        restoreSignals();
-
-        restoreAffinity();
-
-        /* If this is a diverted store (i.e. its "logical" location
-           (typically /nix/store) differs from its "physical" location
-           (e.g. /home/eelco/nix/store), then run the command in a
-           chroot. For non-root users, this requires running it in new
-           mount and user namespaces. Unfortunately,
-           unshare(CLONE_NEWUSER) doesn't work in a multithreaded
-           program (which "nix" is), so we exec() a single-threaded
-           helper program (chrootHelper() below) to do the work. */
-        auto store2 = store.dynamic_pointer_cast<LocalStore>();
-
-        if (store2 && store->storeDir != store2->realStoreDir) {
-            Strings helperArgs = { chrootHelperName, store->storeDir, store2->realStoreDir, cmd };
-            for (auto & arg : args) helperArgs.push_back(arg);
-
-            execv(readLink("/proc/self/exe").c_str(), stringsToCharPtrs(helperArgs).data());
-
-            throw SysError("could not execute chroot helper");
-        }
-
-        execvp(cmd.c_str(), stringsToCharPtrs(args).data());
-
-        throw SysError("unable to exec '%s'", cmd);
+        runProgram(store, *command.begin(), args);
     }
 };