chore(3p/nix): Remove support for plugins r/1408

Plugins seem to not really be used anywhere (I can find one plugin
that's actually defined, and it doesn't seem very useful, especially
since we got rid of builtins.exec) and their presence is adding
additional complexity and potential sources of bugs to an already
unsteady refactor. At some point we may want to bring back
something *like* plugins, but their design will likely be different and
it will definitely be after we have a functioning Nix again.

Change-Id: I3bc40e55917f70bf260fbc208c1705e2e6a7c626
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1291
Tested-by: BuildkiteCI
Reviewed-by: Alyssa Ross <hi@alyssa.is>
Reviewed-by: isomer <isomer@tvl.fyi>

18 files changed, 1 insertions, 128 deletions

diff --git a/third_party/nix/doc/manual/command-ref/conf-file.xml b/third_party/nix/doc/manual/command-ref/conf-file.xml
index 48dce7c950d9..4a5400b1936f 100644
--- a/third_party/nix/doc/manual/command-ref/conf-file.xml
+++ b/third_party/nix/doc/manual/command-ref/conf-file.xml
@@ -598,37 +598,6 @@ password <replaceable>my-password</replaceable>
   </varlistentry>
 
 
-  <varlistentry xml:id="conf-plugin-files">
-    <term><literal>plugin-files</literal></term>
-    <listitem>
-      <para>
-        A list of plugin files to be loaded by Nix. Each of these
-        files will be dlopened by Nix, allowing them to affect
-        execution through static initialization. In particular, these
-        plugins may construct static instances of RegisterPrimOp to
-        add new primops or constants to the expression language,
-        RegisterStoreImplementation to add new store implementations,
-        RegisterCommand to add new subcommands to the
-        <literal>nix</literal> command, and RegisterSetting to add new
-        nix config settings. See the constructors for those types for
-        more details.
-      </para>
-      <para>
-        Since these files are loaded into the same address space as
-        Nix itself, they must be DSOs compatible with the instance of
-        Nix running at the time (i.e. compiled against the same
-        headers, not linked to any incompatible libraries). They
-        should not be linked to any Nix libs directly, as those will
-        be available already at load time.
-      </para>
-      <para>
-        If an entry in the list is a directory, all files in the
-        directory are loaded as plugins (non-recursively).
-      </para>
-    </listitem>
-
-  </varlistentry>
-
   <varlistentry xml:id="conf-pre-build-hook"><term><literal>pre-build-hook</literal></term>
 
     <listitem>
diff --git a/third_party/nix/src/build-remote/build-remote.cc b/third_party/nix/src/build-remote/build-remote.cc
index 2c7e6dbab8cf..82ac2014ef75 100644
--- a/third_party/nix/src/build-remote/build-remote.cc
+++ b/third_party/nix/src/build-remote/build-remote.cc
@@ -68,8 +68,6 @@ static int _main(int argc, char* argv[]) {
 
     settings.maxBuildJobs.set("1");  // hack to make tests with local?root= work
 
-    initPlugins();
-
     auto store = openStore().cast<LocalStore>();
 
     /* It would be more appropriate to use $XDG_RUNTIME_DIR, since
diff --git a/third_party/nix/src/libexpr/primops.hh b/third_party/nix/src/libexpr/primops.hh
index 45f63a541911..388066f39010 100644
--- a/third_party/nix/src/libexpr/primops.hh
+++ b/third_party/nix/src/libexpr/primops.hh
@@ -14,9 +14,7 @@ struct RegisterPrimOp {
   RegisterPrimOp(const std::string& name, size_t arity, PrimOpFun fun);
 };
 
-/* These primops are disabled without enableNativeCode, but plugins
-   may wish to use them in limited contexts without globally enabling
-   them. */
+/* These primops are disabled without enableNativeCode */
 /* Load a ValueInitializer from a DSO and return whatever it initializes */
 void prim_importNative(EvalState& state, const Pos& pos, Value** args,
                        Value& v);
diff --git a/third_party/nix/src/libmain/shared.hh b/third_party/nix/src/libmain/shared.hh
index b749b572c560..60a9e302ff5a 100644
--- a/third_party/nix/src/libmain/shared.hh
+++ b/third_party/nix/src/libmain/shared.hh
@@ -22,7 +22,6 @@ class Exit : public std::exception {
 int handleExceptions(const std::string& programName,
                      const std::function<void()>& fun);
 
-/* Don't forget to call initPlugins() after settings are initialized! */
 void initNix();
 
 void parseCmdLine(
diff --git a/third_party/nix/src/libstore/globals.cc b/third_party/nix/src/libstore/globals.cc
index dccf8d9815a7..06ef3dd0402a 100644
--- a/third_party/nix/src/libstore/globals.cc
+++ b/third_party/nix/src/libstore/globals.cc
@@ -167,35 +167,4 @@ void MaxBuildJobsSetting::set(const std::string& str) {
   }
 }
 
-void initPlugins() {
-  for (const auto& pluginFile : settings.pluginFiles.get()) {
-    Paths pluginFiles;
-    try {
-      auto ents = readDirectory(pluginFile);
-      for (const auto& ent : ents) {
-        pluginFiles.emplace_back(pluginFile + "/" + ent.name);
-      }
-    } catch (SysError& e) {
-      if (e.errNo != ENOTDIR) {
-        throw;
-      }
-      pluginFiles.emplace_back(pluginFile);
-    }
-    for (const auto& file : pluginFiles) {
-      /* handle is purposefully leaked as there may be state in the
-         DSO needed by the action of the plugin. */
-      void* handle = dlopen(file.c_str(), RTLD_LAZY | RTLD_LOCAL);
-      if (handle == nullptr) {
-        throw Error("could not dynamically open plugin file '%s': %s", file,
-                    dlerror());
-      }
-    }
-  }
-
-  /* Since plugins can add settings, try to re-apply previously
-     unknown settings. */
-  globalConfig.reapplyUnknownSettings();
-  globalConfig.warnUnknownSettings();
-}
-
 }  // namespace nix
diff --git a/third_party/nix/src/libstore/globals.hh b/third_party/nix/src/libstore/globals.hh
index 567ec6c42b6c..7799ff28502f 100644
--- a/third_party/nix/src/libstore/globals.hh
+++ b/third_party/nix/src/libstore/globals.hh
@@ -452,21 +452,11 @@ class Settings : public Config {
   Setting<uint64_t> minFreeCheckInterval{
       this, 5, "min-free-check-interval",
       "Number of seconds between checking free disk space."};
-
-  Setting<Paths> pluginFiles{
-      this,
-      {},
-      "plugin-files",
-      "Plugins to dynamically load at nix initialization time."};
 };
 
 // FIXME: don't use a global variable.
 extern Settings settings;
 
-/* This should be called after settings are initialized, but before
-   anything else */
-void initPlugins();
-
 void loadConfFile();
 
 extern const std::string nixVersion;
diff --git a/third_party/nix/src/nix-build/nix-build.cc b/third_party/nix/src/nix-build/nix-build.cc
index 7e3ee11d68f0..7ebb14e1f319 100644
--- a/third_party/nix/src/nix-build/nix-build.cc
+++ b/third_party/nix/src/nix-build/nix-build.cc
@@ -255,8 +255,6 @@ static void _main(int argc, char** argv) {
 
   myArgs.parseCmdline(args);
 
-  initPlugins();
-
   if (packages && fromArgs) {
     throw UsageError("'-p' and '-E' are mutually exclusive");
   }
diff --git a/third_party/nix/src/nix-channel/nix-channel.cc b/third_party/nix/src/nix-channel/nix-channel.cc
index 87cc0a1fea87..837fb861d309 100644
--- a/third_party/nix/src/nix-channel/nix-channel.cc
+++ b/third_party/nix/src/nix-channel/nix-channel.cc
@@ -214,8 +214,6 @@ static int _main(int argc, char** argv) {
                    return true;
                  });
 
-    initPlugins();
-
     switch (cmd) {
       case cNone:
         throw UsageError("no command specified");
diff --git a/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc b/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc
index f6897595cbab..ac8c7d9399fb 100644
--- a/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc
+++ b/third_party/nix/src/nix-collect-garbage/nix-collect-garbage.cc
@@ -82,8 +82,6 @@ static int _main(int argc, char** argv) {
                    return true;
                  });
 
-    initPlugins();
-
     auto profilesDir = settings.nixStateDir + "/profiles";
     if (removeOld) {
       removeOldGenerations(profilesDir);
diff --git a/third_party/nix/src/nix-copy-closure/nix-copy-closure.cc b/third_party/nix/src/nix-copy-closure/nix-copy-closure.cc
index d4ea6a85eca7..3dbe29f2240f 100644
--- a/third_party/nix/src/nix-copy-closure/nix-copy-closure.cc
+++ b/third_party/nix/src/nix-copy-closure/nix-copy-closure.cc
@@ -48,8 +48,6 @@ static int _main(int argc, char** argv) {
           return true;
         });
 
-    initPlugins();
-
     if (sshHost.empty()) {
       throw UsageError("no host name specified");
     }
diff --git a/third_party/nix/src/nix-daemon/nix-daemon.cc b/third_party/nix/src/nix-daemon/nix-daemon.cc
index 5296199380b3..dc5295821f84 100644
--- a/third_party/nix/src/nix-daemon/nix-daemon.cc
+++ b/third_party/nix/src/nix-daemon/nix-daemon.cc
@@ -1107,8 +1107,6 @@ static int _main(int argc, char** argv) {
                    return true;
                  });
 
-    initPlugins();
-
     if (stdio) {
       if (getStoreType() == tDaemon) {
         /* Forward on this connection to the real daemon */
diff --git a/third_party/nix/src/nix-env/nix-env.cc b/third_party/nix/src/nix-env/nix-env.cc
index 820b8cbcaf02..585cfbe3f722 100644
--- a/third_party/nix/src/nix-env/nix-env.cc
+++ b/third_party/nix/src/nix-env/nix-env.cc
@@ -1496,8 +1496,6 @@ static int _main(int argc, char** argv) {
 
     myArgs.parseCmdline(argvToStrings(argc, argv));
 
-    initPlugins();
-
     if (op == nullptr) {
       throw UsageError("no operation specified");
     }
diff --git a/third_party/nix/src/nix-instantiate/nix-instantiate.cc b/third_party/nix/src/nix-instantiate/nix-instantiate.cc
index 6c77a96ebc07..be96943b1234 100644
--- a/third_party/nix/src/nix-instantiate/nix-instantiate.cc
+++ b/third_party/nix/src/nix-instantiate/nix-instantiate.cc
@@ -153,8 +153,6 @@ static int _main(int argc, char** argv) {
 
     myArgs.parseCmdline(argvToStrings(argc, argv));
 
-    initPlugins();
-
     if (evalOnly && !wantsReadWrite) {
       settings.readOnlyMode = true;
     }
diff --git a/third_party/nix/src/nix-prefetch-url/nix-prefetch-url.cc b/third_party/nix/src/nix-prefetch-url/nix-prefetch-url.cc
index b9de2e826b8e..dc0dce345bcd 100644
--- a/third_party/nix/src/nix-prefetch-url/nix-prefetch-url.cc
+++ b/third_party/nix/src/nix-prefetch-url/nix-prefetch-url.cc
@@ -100,8 +100,6 @@ static int _main(int argc, char** argv) {
 
     myArgs.parseCmdline(argvToStrings(argc, argv));
 
-    initPlugins();
-
     if (args.size() > 2) {
       throw UsageError("too many arguments");
     }
diff --git a/third_party/nix/src/nix-store/nix-store.cc b/third_party/nix/src/nix-store/nix-store.cc
index a642780b72e8..7729945b1307 100644
--- a/third_party/nix/src/nix-store/nix-store.cc
+++ b/third_party/nix/src/nix-store/nix-store.cc
@@ -1276,8 +1276,6 @@ static int _main(int argc, char** argv) {
                    return true;
                  });
 
-    initPlugins();
-
     if (op == nullptr) {
       throw UsageError("no operation specified");
     }
diff --git a/third_party/nix/src/nix/main.cc b/third_party/nix/src/nix/main.cc
index a7b6e71bbe93..5536aac53298 100644
--- a/third_party/nix/src/nix/main.cc
+++ b/third_party/nix/src/nix/main.cc
@@ -144,8 +144,6 @@ void mainWrapped(int argc, char** argv) {
 
   args.parseCmdline(argvToStrings(argc, argv));
 
-  initPlugins();
-
   if (!args.command) {
     args.showHelpAndExit();
   }
diff --git a/third_party/nix/tests/plugins.sh b/third_party/nix/tests/plugins.sh
deleted file mode 100644
index 4b1baeddce32..000000000000
--- a/third_party/nix/tests/plugins.sh
+++ /dev/null
@@ -1,7 +0,0 @@
-source common.sh
-
-set -o pipefail
-
-res=$(nix eval '(builtins.anotherNull)' --option setting-set true --option plugin-files $PWD/plugins/libplugintest*)
-
-[ "$res"x = "nullx" ]
diff --git a/third_party/nix/tests/plugins/plugintest.cc b/third_party/nix/tests/plugins/plugintest.cc
deleted file mode 100644
index 353166cffe3b..000000000000
--- a/third_party/nix/tests/plugins/plugintest.cc
+++ /dev/null
@@ -1,23 +0,0 @@
-#include "libutil/config.hh"
-#include "primops.hh"
-
-using namespace nix;
-
-struct MySettings : Config {
-  Setting<bool> settingSet{this, false, "setting-set",
-                           "Whether the plugin-defined setting was set"};
-};
-
-MySettings mySettings;
-
-static GlobalConfig::Register rs(&mySettings);
-
-static void prim_anotherNull(EvalState& state, const Pos& pos, Value** args,
-                             Value& v) {
-  if (mySettings.settingSet)
-    mkNull(v);
-  else
-    mkBool(v, false);
-}
-
-static RegisterPrimOp rp("anotherNull", 0, prim_anotherNull);