Properly scope NIX_BIN_DIR just to the nix CLI

It is no longer feasible to define it in libnixstore, and that's good.

src/libcmd/repl.cc

@@ -7,7 +7,6 @@
 
 #include "ansicolor.hh"
 #include "shared.hh"
-#include "config-global.hh"
 #include "eval.hh"
 #include "eval-settings.hh"
 #include "attr-path.hh"
@@ -77,10 +76,14 @@ struct NixRepl
     int displ;
     StringSet varNames;
 
+    RunNix * runNixPtr;
+
+    void runNix(Path program, const Strings & args, const std::optional<std::string> & input = {});
+
     std::unique_ptr<ReplInteracter> interacter;
 
     NixRepl(const LookupPath & lookupPath, nix::ref<Store> store,ref<EvalState> state,
-            std::function<AnnotatedValues()> getValues);
+            std::function<AnnotatedValues()> getValues, RunNix * runNix);
     virtual ~NixRepl() = default;
 
     ReplExitStatus mainLoop() override;
@@ -125,32 +128,16 @@ std::string removeWhitespace(std::string s)
 
 
 NixRepl::NixRepl(const LookupPath & lookupPath, nix::ref<Store> store, ref<EvalState> state,
-            std::function<NixRepl::AnnotatedValues()> getValues)
+            std::function<NixRepl::AnnotatedValues()> getValues, RunNix * runNix = nullptr)
     : AbstractNixRepl(state)
     , debugTraceIndex(0)
     , getValues(getValues)
     , staticEnv(new StaticEnv(nullptr, state->staticBaseEnv.get()))
+    , runNixPtr{runNix}
     , interacter(make_unique<ReadlineLikeInteracter>(getDataDir() + "/nix/repl-history"))
 {
 }
 
-void runNix(Path program, const Strings & args,
-    const std::optional<std::string> & input = {})
-{
-    auto subprocessEnv = getEnv();
-    subprocessEnv["NIX_CONFIG"] = globalConfig.toKeyValue();
-    //isInteractive avoid grabling interactive commands
-    runProgram2(RunOptions {
-        .program = settings.nixBinDir+ "/" + program,
-        .args = args,
-        .environment = subprocessEnv,
-        .input = input,
-        .isInteractive = true,
-    });
-
-    return;
-}
-
 static std::ostream & showDebugTrace(std::ostream & out, const PosTable & positions, const DebugTrace & dt)
 {
     if (dt.isError)
@@ -635,7 +622,7 @@ ProcessLineResult NixRepl::processLine(std::string line)
                 // When missing, trigger the normal exception
                 // e.g. :doc builtins.foo
                 // behaves like
-                // nix-repl> builtins.foo      
+                // nix-repl> builtins.foo
                 // error: attribute 'foo' missing
                 evalString(arg, v);
                 assert(false);
@@ -836,9 +823,18 @@ void NixRepl::evalString(std::string s, Value & v)
 }
 
 
+void NixRepl::runNix(Path program, const Strings & args, const std::optional<std::string> & input)
+{
+    if (runNixPtr)
+        (*runNixPtr)(program, args, input);
+    else
+        throw Error("Cannot run '%s', no method of calling the Nix CLI provided", program);
+}
+
+
 std::unique_ptr<AbstractNixRepl> AbstractNixRepl::create(
    const LookupPath & lookupPath, nix::ref<Store> store, ref<EvalState> state,
-   std::function<AnnotatedValues()> getValues)
+   std::function<AnnotatedValues()> getValues, RunNix * runNix)
 {
     return std::make_unique<NixRepl>(
         lookupPath,

src/libcmd/repl.hh

@@ -19,9 +19,19 @@ struct AbstractNixRepl
 
     typedef std::vector<std::pair<Value*,std::string>> AnnotatedValues;
 
+    using RunNix = void(Path program, const Strings & args, const std::optional<std::string> & input);
+
+    /**
+     * @param runNix Function to run the nix CLI to support various
+     * `:<something>` commands. Can not be provided, in which case
+     * everything else will still work fine, but those commands won't.
+     */
     static std::unique_ptr<AbstractNixRepl> create(
-        const LookupPath & lookupPath, nix::ref<Store> store, ref<EvalState> state,
-        std::function<AnnotatedValues()> getValues);
+        const LookupPath & lookupPath,
+        nix::ref<Store> store,
+        ref<EvalState> state,
+        std::function<AnnotatedValues()> getValues,
+        RunNix * runNix = nullptr);
 
     static ReplExitStatus runSimple(
         ref<EvalState> evalState,

src/libexpr/primops/fromTOML.cc

@@ -2,7 +2,11 @@
 #include "eval-inline.hh"
 
 #include <sstream>
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wswitch-enum"
 #include <toml.hpp>
+#pragma GCC diagnostic pop
 
 namespace nix {
 

src/libstore/globals.cc

@@ -64,7 +64,6 @@ Settings::Settings()
     , nixStateDir(canonPath(getEnvNonEmpty("NIX_STATE_DIR").value_or(NIX_STATE_DIR)))
     , nixConfDir(canonPath(getEnvNonEmpty("NIX_CONF_DIR").value_or(NIX_CONF_DIR)))
     , nixUserConfFiles(getUserConfigFiles())
-    , nixBinDir(canonPath(getEnvNonEmpty("NIX_BIN_DIR").value_or(NIX_BIN_DIR)))
     , nixManDir(canonPath(NIX_MAN_DIR))
     , nixDaemonSocketFile(canonPath(getEnvNonEmpty("NIX_DAEMON_SOCKET_PATH").value_or(nixStateDir + DEFAULT_SOCKET_PATH)))
 {
@@ -95,34 +94,6 @@ Settings::Settings()
     sandboxPaths = tokenizeString<StringSet>("/System/Library/Frameworks /System/Library/PrivateFrameworks /bin/sh /bin/bash /private/tmp /private/var/tmp /usr/lib");
     allowedImpureHostPrefixes = tokenizeString<StringSet>("/System/Library /usr/lib /dev /bin/sh");
 #endif
-
-    /* Set the build hook location
-
-       For builds we perform a self-invocation, so Nix has to be self-aware.
-       That is, it has to know where it is installed. We don't think it's sentient.
-
-       Normally, nix is installed according to `nixBinDir`, which is set at compile time,
-       but can be overridden. This makes for a great default that works even if this
-       code is linked as a library into some other program whose main is not aware
-       that it might need to be a build remote hook.
-
-       However, it may not have been installed at all. For example, if it's a static build,
-       there's a good chance that it has been moved out of its installation directory.
-       That makes `nixBinDir` useless. Instead, we'll query the OS for the path to the
-       current executable, using `getSelfExe()`.
-
-       As a last resort, we resort to `PATH`. Hopefully we find a `nix` there that's compatible.
-       If you're porting Nix to a new platform, that might be good enough for a while, but
-       you'll want to improve `getSelfExe()` to work on your platform.
-     */
-    std::string nixExePath = nixBinDir + "/nix";
-    if (!pathExists(nixExePath)) {
-        nixExePath = getSelfExe().value_or("nix");
-    }
-    buildHook = {
-        nixExePath,
-        "__build-remote",
-    };
 }
 
 void loadConfFile(AbstractConfig & config)

src/libstore/globals.hh

@@ -84,11 +84,6 @@ public:
      */
     std::vector<Path> nixUserConfFiles;
 
-    /**
-     * The directory where the main programs are stored.
-     */
-    Path nixBinDir;
-
     /**
      * The directory where the man pages are stored.
      */

src/libstore/local.mk

@@ -71,7 +71,6 @@ libstore_CXXFLAGS += \
  -DNIX_STATE_DIR=\"$(NIX_ROOT)$(localstatedir)/nix\" \
  -DNIX_LOG_DIR=\"$(NIX_ROOT)$(localstatedir)/log/nix\" \
  -DNIX_CONF_DIR=\"$(NIX_ROOT)$(sysconfdir)/nix\" \
- -DNIX_BIN_DIR=\"$(NIX_ROOT)$(bindir)\" \
  -DNIX_MAN_DIR=\"$(NIX_ROOT)$(mandir)\" \
  -DLSOF=\"$(NIX_ROOT)$(lsof)\"
 

src/libstore/meson.build

@@ -327,7 +327,6 @@ prefix = get_option('prefix')
 path_opts = [
   # Meson built-ins.
   'datadir',
-  'bindir',
   'mandir',
   'libdir',
   'includedir',
@@ -372,7 +371,6 @@ cpp_str_defines = {
   'NIX_STATE_DIR': state_dir / 'nix',
   'NIX_LOG_DIR':   log_dir,
   'NIX_CONF_DIR':  sysconfdir / 'nix',
-  'NIX_BIN_DIR':   bindir,
   'NIX_MAN_DIR':   mandir,
 }
 

src/libstore/s3-binary-cache-store.cc

@@ -10,6 +10,8 @@
 #include "compression.hh"
 #include "filetransfer.hh"
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wswitch-enum"
 #include <aws/core/Aws.h>
 #include <aws/core/VersionConfig.h>
 #include <aws/core/auth/AWSCredentialsProvider.h>
@@ -25,6 +27,7 @@
 #include <aws/s3/model/ListObjectsRequest.h>
 #include <aws/s3/model/PutObjectRequest.h>
 #include <aws/transfer/TransferManager.h>
+#pragma GCC diagnostic pop
 
 using namespace Aws::Transfer;
 

src/libstore/s3.hh

@@ -8,7 +8,7 @@
 #include <optional>
 #include <string>
 
-namespace Aws { namespace Client { class ClientConfiguration; } }
+namespace Aws { namespace Client { struct ClientConfiguration; } }
 namespace Aws { namespace S3 { class S3Client; } }
 
 namespace nix {

src/nix-channel/nix-channel.cc

@@ -7,6 +7,7 @@
 #include "eval-settings.hh" // for defexpr
 #include "users.hh"
 #include "tarball.hh"
+#include "bin-dir.hh"
 
 #include <fcntl.h>
 #include <regex>
@@ -67,7 +68,7 @@ static void removeChannel(const std::string & name)
     channels.erase(name);
     writeChannels();
 
-    runProgram(settings.nixBinDir + "/nix-env", true, { "--profile", profile, "--uninstall", name });
+    runProgram(getNixBinDir() + "/nix-env", true, { "--profile", profile, "--uninstall", name });
 }
 
 static Path nixDefExpr;
@@ -118,7 +119,7 @@ static void update(const StringSet & channelNames)
 
             bool unpacked = false;
             if (std::regex_search(filename, std::regex("\\.tar\\.(gz|bz2|xz)$"))) {
-                runProgram(settings.nixBinDir + "/nix-build", false, { "--no-out-link", "--expr", "import " + unpackChannelPath +
+                runProgram(getNixBinDir() + "/nix-build", false, { "--no-out-link", "--expr", "import " + unpackChannelPath +
                             "{ name = \"" + cname + "\"; channelName = \"" + name + "\"; src = builtins.storePath \"" + filename + "\"; }" });
                 unpacked = true;
             }
@@ -143,7 +144,7 @@ static void update(const StringSet & channelNames)
     for (auto & expr : exprs)
         envArgs.push_back(std::move(expr));
     envArgs.push_back("--quiet");
-    runProgram(settings.nixBinDir + "/nix-env", false, envArgs);
+    runProgram(getNixBinDir() + "/nix-env", false, envArgs);
 
     // Make the channels appear in nix-env.
     struct stat st;
@@ -244,7 +245,7 @@ static int main_nix_channel(int argc, char ** argv)
             case cListGenerations:
                 if (!args.empty())
                     throw UsageError("'--list-generations' expects no arguments");
-                std::cout << runProgram(settings.nixBinDir + "/nix-env", false, {"--profile", profile, "--list-generations"}) << std::flush;
+                std::cout << runProgram(getNixBinDir() + "/nix-env", false, {"--profile", profile, "--list-generations"}) << std::flush;
                 break;
             case cRollback:
                 if (args.size() > 1)
@@ -256,7 +257,7 @@ static int main_nix_channel(int argc, char ** argv)
                 } else {
                     envArgs.push_back("--rollback");
                 }
-                runProgram(settings.nixBinDir + "/nix-env", false, envArgs);
+                runProgram(getNixBinDir() + "/nix-env", false, envArgs);
                 break;
         }
 

src/nix/bin-dir.cc

@@ -0,0 +1,28 @@
+#include "current-process.hh"
+#include "file-system.hh"
+#include "globals.hh"
+#include "bin-dir.hh"
+
+namespace nix {
+
+const Path & getNixBinDir()
+{
+    static const Path nixBinDir = canonPath(getEnvNonEmpty("NIX_BIN_DIR").value_or(NIX_BIN_DIR));
+
+    return nixBinDir;
+}
+
+void setNixBuildRemoteLocation()
+{
+    std::string nixExePath = getNixBinDir() + "/nix";
+    if (!pathExists(nixExePath)) {
+        nixExePath = getSelfExe().value_or("nix");
+    }
+    settings.buildHook = {
+        nixExePath,
+        "__build-remote",
+    };
+}
+
+
+}

src/nix/bin-dir.hh

@@ -0,0 +1,37 @@
+#pragma once
+///@file
+
+#include "types.hh"
+
+namespace nix {
+
+/**
+ * The directory where the main programs are stored.
+ */
+const Path & getNixBinDir();
+
+/**
+ * @TODO update docs to match status quo, where NIX_BIN_DIR is not defined for libraries
+ *
+ * Set the build hook location
+ *
+ * For builds we perform a self-invocation, so Nix has to be self-aware.
+ * That is, it has to know where it is installed. We don't think it's sentient.
+ *
+ * Normally, nix is installed according to `nixBinDir`, which is set at compile time,
+ * but can be overridden. This makes for a great default that works even if this
+ * code is linked as a library into some other program whose main is not aware
+ * that it might need to be a build remote hook.
+ *
+ * However, it may not have been installed at all. For example, if it's a static build,
+ * there's a good chance that it has been moved out of its installation directory.
+ * That makes `nixBinDir` useless. Instead, we'll query the OS for the path to the
+ * current executable, using `getSelfExe()`.
+ *
+ * As a last resort, we resort to `PATH`. Hopefully we find a `nix` there that's compatible.
+ * If you're porting Nix to a new platform, that might be good enough for a while, but
+ * you'll want to improve `getSelfExe()` to work on your platform.
+ */
+void setNixBuildRemoteLocation();
+
+}

src/nix/local.mk

@@ -26,6 +26,8 @@ endif
 
 nix_CXXFLAGS += $(INCLUDE_libutil) $(INCLUDE_libstore) $(INCLUDE_libfetchers) $(INCLUDE_libexpr) $(INCLUDE_libflake) $(INCLUDE_libmain) -I src/libcmd -I doc/manual $(INCLUDE_nix)
 
+nix_CXXFLAGS += -DNIX_BIN_DIR=\"$(NIX_ROOT)$(bindir)\"
+
 nix_LIBS = libexpr libmain libfetchers libflake libstore libutil libcmd
 
 nix_LDFLAGS = $(THREAD_LDFLAGS) $(SODIUM_LIBS) $(EDITLINE_LIBS) $(BOOST_LDFLAGS) $(LOWDOWN_LIBS)

src/nix/main.cc

@@ -19,6 +19,7 @@
 #include "network-proxy.hh"
 #include "eval-cache.hh"
 #include "flake/flake.hh"
+#include "bin-dir.hh"
 
 #include <sys/types.h>
 #include <regex>
@@ -365,6 +366,7 @@ void mainWrapped(int argc, char * * argv)
     initNix();
     initGC();
     flake::initLib(flakeSettings);
+    setNixBuildRemoteLocation();
 
     #if __linux__
     if (isRootUser()) {