refactor(tvix/libutil): Mark single-argument constructors explicit r/1704

This is the clang-tidy lint 'google-explicit-constructor'.

There's a whole bunch of breakage that was introduced by this, and we
had to opt out a few types of this (esp. the string formatting crap).

In some cases minor other changes have been done to keep the code
working, instead of converting between types (e.g. an explicit
comparison operator implementation for nix::Pid).

Change-Id: I12e1ca51a6bc2c882dba81a2526b9729d26988e7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1832
Tested-by: BuildkiteCI
Reviewed-by: kanepyork <rikingcoding@gmail.com>
Reviewed-by: glittershark <grfn@gws.fyi>

11 files changed, 221 insertions, 200 deletions

diff --git a/third_party/nix/src/libstore/binary-cache-store.cc b/third_party/nix/src/libstore/binary-cache-store.cc
index d38db375edb9..91da7e22659d 100644
--- a/third_party/nix/src/libstore/binary-cache-store.cc
+++ b/third_party/nix/src/libstore/binary-cache-store.cc
@@ -80,13 +80,14 @@ void BinaryCacheStore::getFile(
 
 void BinaryCacheStore::getFile(const std::string& path, Sink& sink) {
   std::promise<std::shared_ptr<std::string>> promise;
-  getFile(path, {[&](std::future<std::shared_ptr<std::string>> result) {
-            try {
-              promise.set_value(result.get());
-            } catch (...) {
-              promise.set_exception(std::current_exception());
-            }
-          }});
+  getFile(path, Callback<std::shared_ptr<std::string>>{
+                    [&](std::future<std::shared_ptr<std::string>> result) {
+                      try {
+                        promise.set_value(result.get());
+                      } catch (...) {
+                        promise.set_exception(std::current_exception());
+                      }
+                    }});
   auto data = promise.get_future().get();
   sink(reinterpret_cast<unsigned char*>(data->data()), data->size());
 }
@@ -280,23 +281,25 @@ void BinaryCacheStore::queryPathInfoUncached(
 
   auto callbackPtr = std::make_shared<decltype(callback)>(std::move(callback));
 
-  getFile(narInfoFile, {[=](std::future<std::shared_ptr<std::string>> fut) {
-            try {
-              auto data = fut.get();
+  getFile(narInfoFile,
+          Callback<std::shared_ptr<std::string>>(
+              [=](std::future<std::shared_ptr<std::string>> fut) {
+                try {
+                  auto data = fut.get();
 
-              if (!data) {
-                return (*callbackPtr)(nullptr);
-              }
+                  if (!data) {
+                    return (*callbackPtr)(nullptr);
+                  }
 
-              stats.narInfoRead++;
+                  stats.narInfoRead++;
 
-              (*callbackPtr)(std::shared_ptr<ValidPathInfo>(
-                  std::make_shared<NarInfo>(*this, *data, narInfoFile)));
+                  (*callbackPtr)(std::shared_ptr<ValidPathInfo>(
+                      std::make_shared<NarInfo>(*this, *data, narInfoFile)));
 
-            } catch (...) {
-              callbackPtr->rethrow();
-            }
-          }});
+                } catch (...) {
+                  callbackPtr->rethrow();
+                }
+              }));
 }
 
 Path BinaryCacheStore::addToStore(const std::string& name, const Path& srcPath,
diff --git a/third_party/nix/src/libstore/build.cc b/third_party/nix/src/libstore/build.cc
index 83aea3899ec7..3dce1566535d 100644
--- a/third_party/nix/src/libstore/build.cc
+++ b/third_party/nix/src/libstore/build.cc
@@ -574,8 +574,8 @@ UserLock::UserLock() {
     }
 
     try {
-      AutoCloseFD fd =
-          open(fnUserLock.c_str(), O_RDWR | O_CREAT | O_CLOEXEC, 0600);
+      AutoCloseFD fd(
+          open(fnUserLock.c_str(), O_RDWR | O_CREAT | O_CLOEXEC, 0600));
       if (!fd) {
         throw SysError(format("opening user lock '%1%'") % fnUserLock);
       }
@@ -698,8 +698,8 @@ HookInstance::HookInstance() {
   });
 
   pid.setSeparatePG(true);
-  fromHook.writeSide = -1;
-  toHook.readSide = -1;
+  fromHook.writeSide = AutoCloseFD(-1);
+  toHook.readSide = AutoCloseFD(-1);
 
   sink = FdSink(toHook.writeSide.get());
   std::map<std::string, Config::SettingInfo> settings;
@@ -712,8 +712,8 @@ HookInstance::HookInstance() {
 
 HookInstance::~HookInstance() {
   try {
-    toHook.writeSide = -1;
-    if (pid != -1) {
+    toHook.writeSide = AutoCloseFD(-1);
+    if (pid != Pid(-1)) {
       pid.kill();
     }
   } catch (...) {
@@ -1056,7 +1056,7 @@ DerivationGoal::~DerivationGoal() {
 inline bool DerivationGoal::needsHashRewrite() { return !useChroot; }
 
 void DerivationGoal::killChild() {
-  if (pid != -1) {
+  if (pid != Pid(-1)) {
     worker.childTerminated(this);
 
     if (buildUser) {
@@ -1066,14 +1066,14 @@ void DerivationGoal::killChild() {
          it won't be killed, and we'll potentially lock up in
          pid.wait().  So also send a conventional kill to the
          child. */
-      ::kill(-pid, SIGKILL); /* ignore the result */
+      ::kill(-static_cast<pid_t>(pid), SIGKILL); /* ignore the result */
       buildUser->kill();
       pid.wait();
     } else {
       pid.kill();
     }
 
-    assert(pid == -1);
+    assert(pid == Pid(-1));
   }
 
   hook.reset();
@@ -1572,10 +1572,10 @@ void DerivationGoal::buildDone() {
 
   /* Close the read side of the logger pipe. */
   if (hook) {
-    hook->builderOut.readSide = -1;
-    hook->fromHook.readSide = -1;
+    hook->builderOut.readSide = AutoCloseFD(-1);
+    hook->fromHook.readSide = AutoCloseFD(-1);
   } else {
-    builderOut.readSide = -1;
+    builderOut.readSide = AutoCloseFD(-1);
   }
 
   /* Close the log file. */
@@ -1830,7 +1830,7 @@ HookReply DerivationGoal::tryBuildHook() {
   hook->sink << missingPaths;
 
   hook->sink = FdSink();
-  hook->toHook.writeSide = -1;
+  hook->toHook.writeSide = AutoCloseFD(-1);
 
   /* Create the log file and pipe. */
   Path logFile = openLogFile();
@@ -2268,7 +2268,7 @@ void DerivationGoal::startBuilder() {
   /* Create a pipe to get the output of the builder. */
   // builderOut.create();
 
-  builderOut.readSide = posix_openpt(O_RDWR | O_NOCTTY);
+  builderOut.readSide = AutoCloseFD(posix_openpt(O_RDWR | O_NOCTTY));
   if (!builderOut.readSide) {
     throw SysError("opening pseudoterminal master");
   }
@@ -2300,7 +2300,8 @@ void DerivationGoal::startBuilder() {
     throw SysError("unlocking pseudoterminal");
   }
 
-  builderOut.writeSide = open(slaveName.c_str(), O_RDWR | O_NOCTTY);
+  builderOut.writeSide =
+      AutoCloseFD(open(slaveName.c_str(), O_RDWR | O_NOCTTY));
   if (!builderOut.writeSide) {
     throw SysError("opening pseudoterminal slave");
   }
@@ -2364,7 +2365,7 @@ void DerivationGoal::startBuilder() {
 
     userNamespaceSync.create();
 
-    Pid helper = startProcess(
+    Pid helper(startProcess(
         [&]() {
           /* Drop additional groups here because we can't do it
              after we've created the new user namespace.  FIXME:
@@ -2421,7 +2422,7 @@ void DerivationGoal::startBuilder() {
           writeFull(builderOut.writeSide.get(), std::to_string(child) + "\n");
           _exit(0);
         },
-        options);
+        options));
 
     int res = helper.wait();
     if (res != 0 && settings.sandboxFallback) {
@@ -2432,7 +2433,7 @@ void DerivationGoal::startBuilder() {
       throw Error("unable to start build process");
     }
 
-    userNamespaceSync.readSide = -1;
+    userNamespaceSync.readSide = AutoCloseFD(-1);
 
     pid_t tmp;
     if (!absl::SimpleAtoi(readLine(builderOut.readSide.get()), &tmp)) {
@@ -2446,18 +2447,19 @@ void DerivationGoal::startBuilder() {
     uid_t hostUid = buildUser ? buildUser->getUID() : getuid();
     uid_t hostGid = buildUser ? buildUser->getGID() : getgid();
 
-    writeFile("/proc/" + std::to_string(pid) + "/uid_map",
+    writeFile("/proc/" + std::to_string(static_cast<pid_t>(pid)) + "/uid_map",
               (format("%d %d 1") % sandboxUid % hostUid).str());
 
-    writeFile("/proc/" + std::to_string(pid) + "/setgroups", "deny");
+    writeFile("/proc/" + std::to_string(static_cast<pid_t>(pid)) + "/setgroups",
+              "deny");
 
-    writeFile("/proc/" + std::to_string(pid) + "/gid_map",
+    writeFile("/proc/" + std::to_string(static_cast<pid_t>(pid)) + "/gid_map",
               (format("%d %d 1") % sandboxGid % hostGid).str());
 
     /* Signal the builder that we've updated its user
        namespace. */
     writeFull(userNamespaceSync.writeSide.get(), "1");
-    userNamespaceSync.writeSide = -1;
+    userNamespaceSync.writeSide = AutoCloseFD(-1);
 
   } else
 #endif
@@ -2468,7 +2470,7 @@ void DerivationGoal::startBuilder() {
 
   /* parent */
   pid.setSeparatePG(true);
-  builderOut.writeSide = -1;
+  builderOut.writeSide = AutoCloseFD(-1);
   worker.childStarted(shared_from_this(), {builderOut.readSide.get()}, true,
                       true);
 
@@ -2837,13 +2839,13 @@ void DerivationGoal::runChild() {
 
 #if __linux__
     if (useChroot) {
-      userNamespaceSync.writeSide = -1;
+      userNamespaceSync.writeSide = AutoCloseFD(-1);
 
       if (drainFD(userNamespaceSync.readSide.get()) != "1") {
         throw Error("user namespace initialisation failed");
       }
 
-      userNamespaceSync.readSide = -1;
+      userNamespaceSync.readSide = AutoCloseFD(-1);
 
       if (privateNetwork) {
         /* Initialise the loopback interface. */
@@ -3738,8 +3740,8 @@ Path DerivationGoal::openLogFile() {
   Path logFileName = fmt("%s/%s%s", dir, std::string(baseName, 2),
                          settings.compressLog ? ".bz2" : "");
 
-  fdLogFile =
-      open(logFileName.c_str(), O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, 0666);
+  fdLogFile = AutoCloseFD(open(logFileName.c_str(),
+                               O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, 0666));
   if (!fdLogFile) {
     throw SysError(format("creating log file '%1%'") % logFileName);
   }
@@ -3765,7 +3767,7 @@ void DerivationGoal::closeLogFile() {
     logFileSink->flush();
   }
   logSink = logFileSink = nullptr;
-  fdLogFile = -1;
+  fdLogFile = AutoCloseFD(-1);
 }
 
 void DerivationGoal::deleteTmpDir(bool force) {
@@ -4163,7 +4165,7 @@ void SubstitutionGoal::tryToRun() {
   thr = std::thread([this]() {
     try {
       /* Wake up the worker loop when we're done. */
-      Finally updateStats([this]() { outPipe.writeSide = -1; });
+      Finally updateStats([this]() { outPipe.writeSide = AutoCloseFD(-1); });
 
       copyStorePath(ref<Store>(sub),
                     ref<Store>(worker.store.shared_from_this()), storePath,
diff --git a/third_party/nix/src/libstore/download.cc b/third_party/nix/src/libstore/download.cc
index 60a409d0dc4f..ee2ce8152dbc 100644
--- a/third_party/nix/src/libstore/download.cc
+++ b/third_party/nix/src/libstore/download.cc
@@ -744,13 +744,15 @@ ref<Downloader> makeDownloader() { return make_ref<CurlDownloader>(); }
 std::future<DownloadResult> Downloader::enqueueDownload(
     const DownloadRequest& request) {
   auto promise = std::make_shared<std::promise<DownloadResult>>();
-  enqueueDownload(request, {[promise](std::future<DownloadResult> fut) {
-                    try {
-                      promise->set_value(fut.get());
-                    } catch (...) {
-                      promise->set_exception(std::current_exception());
-                    }
-                  }});
+  enqueueDownload(
+      request,
+      Callback<DownloadResult>([promise](std::future<DownloadResult> fut) {
+        try {
+          promise->set_value(fut.get());
+        } catch (...) {
+          promise->set_exception(std::current_exception());
+        }
+      }));
   return promise->get_future();
 }
 
@@ -807,17 +809,18 @@ void Downloader::download(DownloadRequest&& request, Sink& sink) {
     state->avail.notify_one();
   };
 
-  enqueueDownload(request, {[_state](std::future<DownloadResult> fut) {
-                    auto state(_state->lock());
-                    state->quit = true;
-                    try {
-                      fut.get();
-                    } catch (...) {
-                      state->exc = std::current_exception();
-                    }
-                    state->avail.notify_one();
-                    state->request.notify_one();
-                  }});
+  enqueueDownload(request, Callback<DownloadResult>(
+                               [_state](std::future<DownloadResult> fut) {
+                                 auto state(_state->lock());
+                                 state->quit = true;
+                                 try {
+                                   fut.get();
+                                 } catch (...) {
+                                   state->exc = std::current_exception();
+                                 }
+                                 state->avail.notify_one();
+                                 state->request.notify_one();
+                               }));
 
   while (true) {
     checkInterrupt();
diff --git a/third_party/nix/src/libstore/gc.cc b/third_party/nix/src/libstore/gc.cc
index 596046e4f324..4f04e09a7555 100644
--- a/third_party/nix/src/libstore/gc.cc
+++ b/third_party/nix/src/libstore/gc.cc
@@ -35,8 +35,9 @@ AutoCloseFD LocalStore::openGCLock(LockType lockType) {
 
   DLOG(INFO) << "acquiring global GC lock " << fnGCLock;
 
-  AutoCloseFD fdGCLock =
-      open(fnGCLock.c_str(), O_RDWR | O_CREAT | O_CLOEXEC, 0600);
+  AutoCloseFD fdGCLock(
+      open(fnGCLock.c_str(), O_RDWR | O_CREAT | O_CLOEXEC, 0600));
+
   if (!fdGCLock) {
     throw SysError(format("opening global GC lock '%1%'") % fnGCLock);
   }
@@ -160,7 +161,7 @@ void LocalStore::addTempRoot(const Path& path) {
 
       state->fdTempRoots = openLockFile(fnTempRoots, true);
 
-      fdGCLock = -1;
+      fdGCLock = AutoCloseFD(-1);
 
       DLOG(INFO) << "acquiring read lock on " << fnTempRoots;
       lockFile(state->fdTempRoots.get(), ltRead, true);
@@ -886,7 +887,7 @@ void LocalStore::collectGarbage(const GCOptions& options, GCResults& results) {
   }
 
   /* Allow other processes to add to the store from here on. */
-  fdGCLock = -1;
+  fdGCLock = AutoCloseFD(-1);
   fds.clear();
 
   /* Delete the trash directory. */
diff --git a/third_party/nix/src/libstore/http-binary-cache-store.cc b/third_party/nix/src/libstore/http-binary-cache-store.cc
index 8ab07033b191..c713ac43c47a 100644
--- a/third_party/nix/src/libstore/http-binary-cache-store.cc
+++ b/third_party/nix/src/libstore/http-binary-cache-store.cc
@@ -135,20 +135,22 @@ class HttpBinaryCacheStore : public BinaryCacheStore {
         std::make_shared<decltype(callback)>(std::move(callback));
 
     getDownloader()->enqueueDownload(
-        request, {[callbackPtr, this](std::future<DownloadResult> result) {
-          try {
-            (*callbackPtr)(result.get().data);
-          } catch (DownloadError& e) {
-            if (e.error == Downloader::NotFound ||
-                e.error == Downloader::Forbidden) {
-              return (*callbackPtr)(std::shared_ptr<std::string>());
-            }
-            maybeDisable();
-            callbackPtr->rethrow();
-          } catch (...) {
-            callbackPtr->rethrow();
-          }
-        }});
+        request,
+        Callback<DownloadResult>{
+            [callbackPtr, this](std::future<DownloadResult> result) {
+              try {
+                (*callbackPtr)(result.get().data);
+              } catch (DownloadError& e) {
+                if (e.error == Downloader::NotFound ||
+                    e.error == Downloader::Forbidden) {
+                  return (*callbackPtr)(std::shared_ptr<std::string>());
+                }
+                maybeDisable();
+                callbackPtr->rethrow();
+              } catch (...) {
+                callbackPtr->rethrow();
+              }
+            }});
   }
 };
 
diff --git a/third_party/nix/src/libstore/local-store.cc b/third_party/nix/src/libstore/local-store.cc
index 5e3271a5f3cc..aca305e1a52f 100644
--- a/third_party/nix/src/libstore/local-store.cc
+++ b/third_party/nix/src/libstore/local-store.cc
@@ -135,8 +135,8 @@ LocalStore::LocalStore(const Params& params)
     struct stat st;
     if (stat(reservedPath.c_str(), &st) == -1 ||
         st.st_size != settings.reservedSize) {
-      AutoCloseFD fd =
-          open(reservedPath.c_str(), O_WRONLY | O_CREAT | O_CLOEXEC, 0600);
+      AutoCloseFD fd(
+          open(reservedPath.c_str(), O_WRONLY | O_CREAT | O_CLOEXEC, 0600));
       int res = -1;
 #if HAVE_POSIX_FALLOCATE
       res = posix_fallocate(fd.get(), 0, settings.reservedSize);
@@ -288,7 +288,7 @@ LocalStore::~LocalStore() {
   try {
     auto state(_state.lock());
     if (state->fdTempRoots) {
-      state->fdTempRoots = -1;
+      state->fdTempRoots = AutoCloseFD(-1);
       unlink(fnTempRoots.c_str());
     }
   } catch (...) {
@@ -1278,7 +1278,7 @@ bool LocalStore::verifyStore(bool checkContents, RepairFlag repair) {
   PathSet validPaths;
   PathSet done;
 
-  fdGCLock = -1;
+  fdGCLock = AutoCloseFD(-1);
 
   for (auto& i : validPaths2) {
     verifyPath(i, store, done, validPaths, repair, errors);
diff --git a/third_party/nix/src/libstore/misc.cc b/third_party/nix/src/libstore/misc.cc
index 8a05d55accd0..44e67ada369c 100644
--- a/third_party/nix/src/libstore/misc.cc
+++ b/third_party/nix/src/libstore/misc.cc
@@ -38,74 +38,76 @@ void Store::computeFSClosure(const PathSet& startPaths, PathSet& paths_,
     }
 
     queryPathInfo(
-        path, {[&, path](std::future<ref<ValidPathInfo>> fut) {
-          // FIXME: calls to isValidPath() should be async
-
-          try {
-            auto info = fut.get();
-
-            if (flipDirection) {
-              PathSet referrers;
-              queryReferrers(path, referrers);
-              for (auto& ref : referrers) {
-                if (ref != path) {
-                  enqueue(ref);
-                }
-              }
+        path,
+        Callback<ref<ValidPathInfo>>(
+            [&, path](std::future<ref<ValidPathInfo>> fut) {
+              // FIXME: calls to isValidPath() should be async
+
+              try {
+                auto info = fut.get();
+
+                if (flipDirection) {
+                  PathSet referrers;
+                  queryReferrers(path, referrers);
+                  for (auto& ref : referrers) {
+                    if (ref != path) {
+                      enqueue(ref);
+                    }
+                  }
 
-              if (includeOutputs) {
-                for (auto& i : queryValidDerivers(path)) {
-                  enqueue(i);
-                }
-              }
+                  if (includeOutputs) {
+                    for (auto& i : queryValidDerivers(path)) {
+                      enqueue(i);
+                    }
+                  }
 
-              if (includeDerivers && isDerivation(path)) {
-                for (auto& i : queryDerivationOutputs(path)) {
-                  if (isValidPath(i) && queryPathInfo(i)->deriver == path) {
-                    enqueue(i);
+                  if (includeDerivers && isDerivation(path)) {
+                    for (auto& i : queryDerivationOutputs(path)) {
+                      if (isValidPath(i) && queryPathInfo(i)->deriver == path) {
+                        enqueue(i);
+                      }
+                    }
+                  }
+
+                } else {
+                  for (auto& ref : info->references) {
+                    if (ref != path) {
+                      enqueue(ref);
+                    }
                   }
-                }
-              }
 
-            } else {
-              for (auto& ref : info->references) {
-                if (ref != path) {
-                  enqueue(ref);
+                  if (includeOutputs && isDerivation(path)) {
+                    for (auto& i : queryDerivationOutputs(path)) {
+                      if (isValidPath(i)) {
+                        enqueue(i);
+                      }
+                    }
+                  }
+
+                  if (includeDerivers && isValidPath(info->deriver)) {
+                    enqueue(info->deriver);
+                  }
                 }
-              }
 
-              if (includeOutputs && isDerivation(path)) {
-                for (auto& i : queryDerivationOutputs(path)) {
-                  if (isValidPath(i)) {
-                    enqueue(i);
+                {
+                  auto state(state_.lock());
+                  assert(state->pending);
+                  if (--state->pending == 0u) {
+                    done.notify_one();
                   }
                 }
-              }
-
-              if (includeDerivers && isValidPath(info->deriver)) {
-                enqueue(info->deriver);
-              }
-            }
-
-            {
-              auto state(state_.lock());
-              assert(state->pending);
-              if (--state->pending == 0u) {
-                done.notify_one();
-              }
-            }
-
-          } catch (...) {
-            auto state(state_.lock());
-            if (!state->exc) {
-              state->exc = std::current_exception();
-            }
-            assert(state->pending);
-            if (--state->pending == 0u) {
-              done.notify_one();
-            }
-          };
-        }});
+
+              } catch (...) {
+                auto state(state_.lock());
+                if (!state->exc) {
+                  state->exc = std::current_exception();
+                }
+                assert(state->pending);
+                if (--state->pending == 0u) {
+                  done.notify_one();
+                }
+              };
+            }));
   };
 
   for (auto& startPath : startPaths) {
diff --git a/third_party/nix/src/libstore/pathlocks.cc b/third_party/nix/src/libstore/pathlocks.cc
index 4b153856d283..8a874adbe913 100644
--- a/third_party/nix/src/libstore/pathlocks.cc
+++ b/third_party/nix/src/libstore/pathlocks.cc
@@ -15,9 +15,9 @@
 namespace nix {
 
 AutoCloseFD openLockFile(const Path& path, bool create) {
-  AutoCloseFD fd;
+  AutoCloseFD fd(
+      open(path.c_str(), O_CLOEXEC | O_RDWR | (create ? O_CREAT : 0), 0600));
 
-  fd = open(path.c_str(), O_CLOEXEC | O_RDWR | (create ? O_CREAT : 0), 0600);
   if (!fd && (create || errno != ENOENT)) {
     throw SysError(format("opening lock file '%1%'") % path);
   }
diff --git a/third_party/nix/src/libstore/remote-fs-accessor.cc b/third_party/nix/src/libstore/remote-fs-accessor.cc
index d5b20288479c..4178030b55d6 100644
--- a/third_party/nix/src/libstore/remote-fs-accessor.cc
+++ b/third_party/nix/src/libstore/remote-fs-accessor.cc
@@ -70,7 +70,7 @@ std::pair<ref<FSAccessor>, Path> RemoteFSAccessor::fetch(const Path& path_) {
 
       auto narAccessor = makeLazyNarAccessor(
           listing, [cacheFile](uint64_t offset, uint64_t length) {
-            AutoCloseFD fd = open(cacheFile.c_str(), O_RDONLY | O_CLOEXEC);
+            AutoCloseFD fd(open(cacheFile.c_str(), O_RDONLY | O_CLOEXEC));
             if (!fd) {
               throw SysError("opening NAR cache file '%s'", cacheFile);
             }
diff --git a/third_party/nix/src/libstore/ssh.cc b/third_party/nix/src/libstore/ssh.cc
index 52fbe6425458..7d5fe6d10937 100644
--- a/third_party/nix/src/libstore/ssh.cc
+++ b/third_party/nix/src/libstore/ssh.cc
@@ -88,8 +88,8 @@ std::unique_ptr<SSHMaster::Connection> SSHMaster::startCommand(
       },
       options);
 
-  in.readSide = -1;
-  out.writeSide = -1;
+  in.readSide = AutoCloseFD(-1);
+  out.writeSide = AutoCloseFD(-1);
 
   conn->out = std::move(out.readSide);
   conn->in = std::move(in.writeSide);
@@ -104,7 +104,7 @@ Path SSHMaster::startMaster() {
 
   auto state(state_.lock());
 
-  if (state->sshMaster != -1) {
+  if (state->sshMaster != Pid(-1)) {
     return state->socketPath;
   }
 
@@ -142,7 +142,7 @@ Path SSHMaster::startMaster() {
       },
       options);
 
-  out.writeSide = -1;
+  out.writeSide = AutoCloseFD(-1);
 
   std::string reply;
   try {
diff --git a/third_party/nix/src/libstore/store-api.cc b/third_party/nix/src/libstore/store-api.cc
index 0ea6b1d62c34..d7ca54fa9a77 100644
--- a/third_party/nix/src/libstore/store-api.cc
+++ b/third_party/nix/src/libstore/store-api.cc
@@ -392,7 +392,10 @@ Path Store::computeStorePathForText(const std::string& name,
 }
 
 Store::Store(const Params& params)
-    : Config(params), state({(size_t)pathInfoCacheSize}) {}
+    : Config(params),
+      state(Sync<State>{
+          State{LRUCache<std::string, std::shared_ptr<ValidPathInfo>>(
+              (size_t)pathInfoCacheSize)}}) {}
 
 std::string Store::getUri() { return ""; }
 
@@ -446,13 +449,15 @@ bool Store::isValidPathUncached(const Path& path) {
 ref<const ValidPathInfo> Store::queryPathInfo(const Path& storePath) {
   std::promise<ref<ValidPathInfo>> promise;
 
-  queryPathInfo(storePath, {[&](std::future<ref<ValidPathInfo>> result) {
-                  try {
-                    promise.set_value(result.get());
-                  } catch (...) {
-                    promise.set_exception(std::current_exception());
-                  }
-                }});
+  queryPathInfo(
+      storePath,
+      Callback<ref<ValidPathInfo>>([&](std::future<ref<ValidPathInfo>> result) {
+        try {
+          promise.set_value(result.get());
+        } catch (...) {
+          promise.set_exception(std::current_exception());
+        }
+      }));
 
   return promise.get_future().get();
 }
@@ -503,31 +508,33 @@ void Store::queryPathInfo(const Path& storePath,
   auto callbackPtr = std::make_shared<decltype(callback)>(std::move(callback));
 
   queryPathInfoUncached(
-      storePath, {[this, storePath, hashPart, callbackPtr](
-                      std::future<std::shared_ptr<ValidPathInfo>> fut) {
-        try {
-          auto info = fut.get();
+      storePath,
+      Callback<std::shared_ptr<ValidPathInfo>>{
+          [this, storePath, hashPart,
+           callbackPtr](std::future<std::shared_ptr<ValidPathInfo>> fut) {
+            try {
+              auto info = fut.get();
 
-          if (diskCache) {
-            diskCache->upsertNarInfo(getUri(), hashPart, info);
-          }
+              if (diskCache) {
+                diskCache->upsertNarInfo(getUri(), hashPart, info);
+              }
 
-          {
-            auto state_(state.lock());
-            state_->pathInfoCache.upsert(hashPart, info);
-          }
+              {
+                auto state_(state.lock());
+                state_->pathInfoCache.upsert(hashPart, info);
+              }
 
-          if (!info || (info->path != storePath &&
-                        !storePathToName(storePath).empty())) {
-            stats.narInfoMissing++;
-            throw InvalidPath("path '%s' is not valid", storePath);
-          }
+              if (!info || (info->path != storePath &&
+                            !storePathToName(storePath).empty())) {
+                stats.narInfoMissing++;
+                throw InvalidPath("path '%s' is not valid", storePath);
+              }
 
-          (*callbackPtr)(ref<ValidPathInfo>(info));
-        } catch (...) {
-          callbackPtr->rethrow();
-        }
-      }});
+              (*callbackPtr)(ref<ValidPathInfo>(info));
+            } catch (...) {
+              callbackPtr->rethrow();
+            }
+          }});
 }
 
 PathSet Store::queryValidPaths(const PathSet& paths,
@@ -545,21 +552,22 @@ PathSet Store::queryValidPaths(const PathSet& paths,
 
   auto doQuery = [&](const Path& path) {
     checkInterrupt();
-    queryPathInfo(
-        path, {[path, &state_, &wakeup](std::future<ref<ValidPathInfo>> fut) {
-          auto state(state_.lock());
-          try {
-            auto info = fut.get();
-            state->valid.insert(path);
-          } catch (InvalidPath&) {
-          } catch (...) {
-            state->exc = std::current_exception();
-          }
-          assert(state->left);
-          if (--state->left == 0u) {
-            wakeup.notify_one();
-          }
-        }});
+    queryPathInfo(path, Callback<ref<ValidPathInfo>>(
+                            [path, &state_,
+                             &wakeup](std::future<ref<ValidPathInfo>> fut) {
+                              auto state(state_.lock());
+                              try {
+                                auto info = fut.get();
+                                state->valid.insert(path);
+                              } catch (InvalidPath&) {
+                              } catch (...) {
+                                state->exc = std::current_exception();
+                              }
+                              assert(state->left);
+                              if (--state->left == 0u) {
+                                wakeup.notify_one();
+                              }
+                            }));
   };
 
   for (auto& path : paths) {