diff --git a/src/hydra-eval-jobs/hydra-eval-jobs.cc b/src/hydra-eval-jobs/hydra-eval-jobs.cc
index 5cfc3a52..9cc1d50c 100644
--- a/src/hydra-eval-jobs/hydra-eval-jobs.cc
+++ b/src/hydra-eval-jobs/hydra-eval-jobs.cc
@@ -8,8 +8,6 @@
 #include "eval.hh"
 #include "eval-inline.hh"
 #include "eval-settings.hh"
-#include "signals.hh"
-#include "terminal.hh"
 #include "util.hh"
 #include "get-drvs.hh"
 #include "globals.hh"
@@ -97,7 +95,7 @@ static std::string queryMetaStrings(EvalState & state, DrvInfo & drv, const std:
     rec = [&](Value & v) {
         state.forceValue(v, noPos);
         if (v.type() == nString)
-            res.emplace_back(v.string_view());
+            res.push_back(v.string.s);
         else if (v.isList())
             for (unsigned int n = 0; n < v.listSize(); ++n)
                 rec(*v.listElems()[n]);
@@ -228,7 +226,7 @@ static void worker(
                         auto v = a->value->listElems()[n];
                         state.forceValue(*v, noPos);
                         if (v->type() == nString)
-                            job["namedConstituents"].push_back(v->string_view());
+                            job["namedConstituents"].push_back(v->str());
                     }
                 }
 
diff --git a/src/hydra-evaluator/hydra-evaluator.cc b/src/hydra-evaluator/hydra-evaluator.cc
index 75506ff8..a1ccf047 100644
--- a/src/hydra-evaluator/hydra-evaluator.cc
+++ b/src/hydra-evaluator/hydra-evaluator.cc
@@ -2,7 +2,6 @@
 #include "hydra-config.hh"
 #include "pool.hh"
 #include "shared.hh"
-#include "signals.hh"
 
 #include <algorithm>
 #include <thread>
diff --git a/src/hydra-queue-runner/build-remote.cc b/src/hydra-queue-runner/build-remote.cc
index 02b82d2b..f9e61df5 100644
--- a/src/hydra-queue-runner/build-remote.cc
+++ b/src/hydra-queue-runner/build-remote.cc
@@ -9,8 +9,6 @@
 #include "path.hh"
 #include "serve-protocol.hh"
 #include "state.hh"
-#include "current-process.hh"
-#include "processes.hh"
 #include "util.hh"
 #include "serve-protocol.hh"
 #include "serve-protocol-impl.hh"
diff --git a/src/hydra-queue-runner/build-result.cc b/src/hydra-queue-runner/build-result.cc
index ffdc37b7..b5c99317 100644
--- a/src/hydra-queue-runner/build-result.cc
+++ b/src/hydra-queue-runner/build-result.cc
@@ -1,7 +1,7 @@
 #include "hydra-build-result.hh"
 #include "store-api.hh"
 #include "util.hh"
-#include "source-accessor.hh"
+#include "fs-accessor.hh"
 
 #include <regex>
 
@@ -63,7 +63,7 @@ BuildOutput getBuildOutput(
 
         auto productsFile = narMembers.find(outputS + "/nix-support/hydra-build-products");
         if (productsFile == narMembers.end() ||
-            productsFile->second.type != SourceAccessor::Type::tRegular)
+            productsFile->second.type != FSAccessor::Type::tRegular)
             continue;
         assert(productsFile->second.contents);
 
@@ -94,7 +94,7 @@ BuildOutput getBuildOutput(
 
             product.name = product.path == store->printStorePath(output) ? "" : baseNameOf(product.path);
 
-            if (file->second.type == SourceAccessor::Type::tRegular) {
+            if (file->second.type == FSAccessor::Type::tRegular) {
                 product.isRegular = true;
                 product.fileSize = file->second.fileSize.value();
                 product.sha256hash = file->second.sha256.value();
@@ -116,7 +116,7 @@ BuildOutput getBuildOutput(
 
             auto file = narMembers.find(product.path);
             assert(file != narMembers.end());
-            if (file->second.type == SourceAccessor::Type::tDirectory)
+            if (file->second.type == FSAccessor::Type::tDirectory)
                 res.products.push_back(product);
         }
     }
@@ -125,7 +125,7 @@ BuildOutput getBuildOutput(
     for (auto & output : outputs) {
         auto file = narMembers.find(store->printStorePath(output) + "/nix-support/hydra-release-name");
         if (file == narMembers.end() ||
-            file->second.type != SourceAccessor::Type::tRegular)
+            file->second.type != FSAccessor::Type::tRegular)
             continue;
         res.releaseName = trim(file->second.contents.value());
         // FIXME: validate release name
@@ -135,7 +135,7 @@ BuildOutput getBuildOutput(
     for (auto & output : outputs) {
         auto file = narMembers.find(store->printStorePath(output) + "/nix-support/hydra-metrics");
         if (file == narMembers.end() ||
-            file->second.type != SourceAccessor::Type::tRegular)
+            file->second.type != FSAccessor::Type::tRegular)
             continue;
         for (auto & line : tokenizeString<Strings>(file->second.contents.value(), "\n")) {
             auto fields = tokenizeString<std::vector<std::string>>(line);
diff --git a/src/hydra-queue-runner/hydra-queue-runner.cc b/src/hydra-queue-runner/hydra-queue-runner.cc
index b6eca0d1..5f288dc7 100644
--- a/src/hydra-queue-runner/hydra-queue-runner.cc
+++ b/src/hydra-queue-runner/hydra-queue-runner.cc
@@ -11,7 +11,6 @@
 
 #include <nlohmann/json.hpp>
 
-#include "signals.hh"
 #include "state.hh"
 #include "hydra-build-result.hh"
 #include "store-api.hh"
@@ -535,7 +534,7 @@ void State::markSucceededBuild(pqxx::work & txn, Build::ptr build,
              product.type,
              product.subtype,
              product.fileSize ? std::make_optional(*product.fileSize) : std::nullopt,
-             product.sha256hash ? std::make_optional(product.sha256hash->to_string(HashFormat::Base16, false)) : std::nullopt,
+             product.sha256hash ? std::make_optional(product.sha256hash->to_string(Base16, false)) : std::nullopt,
              product.path,
              product.name,
              product.defaultPath);
diff --git a/src/hydra-queue-runner/nar-extractor.cc b/src/hydra-queue-runner/nar-extractor.cc
index 3c6857bf..9f0eb431 100644
--- a/src/hydra-queue-runner/nar-extractor.cc
+++ b/src/hydra-queue-runner/nar-extractor.cc
@@ -24,13 +24,13 @@ struct Extractor : ParseSink
 
     void createDirectory(const Path & path) override
     {
-        members.insert_or_assign(prefix + path, NarMemberData { .type = SourceAccessor::Type::tDirectory });
+        members.insert_or_assign(prefix + path, NarMemberData { .type = FSAccessor::Type::tDirectory });
     }
 
     void createRegularFile(const Path & path) override
     {
         curMember = &members.insert_or_assign(prefix + path, NarMemberData {
-            .type = SourceAccessor::Type::tRegular,
+            .type = FSAccessor::Type::tRegular,
             .fileSize = 0,
             .contents = filesToKeep.count(path) ? std::optional("") : std::nullopt,
         }).first->second;
@@ -66,14 +66,8 @@ struct Extractor : ParseSink
 
     void createSymlink(const Path & path, const std::string & target) override
     {
-        members.insert_or_assign(prefix + path, NarMemberData { .type = SourceAccessor::Type::tSymlink });
+        members.insert_or_assign(prefix + path, NarMemberData { .type = FSAccessor::Type::tSymlink });
     }
-
-    void isExecutable() override
-    { }
-
-    void closeRegularFile() override
-    { }
 };
 
 
diff --git a/src/hydra-queue-runner/nar-extractor.hh b/src/hydra-queue-runner/nar-extractor.hh
index 2634135b..45b2706c 100644
--- a/src/hydra-queue-runner/nar-extractor.hh
+++ b/src/hydra-queue-runner/nar-extractor.hh
@@ -1,13 +1,13 @@
 #pragma once
 
-#include "source-accessor.hh"
+#include "fs-accessor.hh"
 #include "types.hh"
 #include "serialise.hh"
 #include "hash.hh"
 
 struct NarMemberData
 {
-    nix::SourceAccessor::Type type;
+    nix::FSAccessor::Type type;
     std::optional<uint64_t> fileSize;
     std::optional<std::string> contents;
     std::optional<nix::Hash> sha256;
diff --git a/src/libhydra/db.hh b/src/libhydra/db.hh
index 1e927573..00e8f406 100644
--- a/src/libhydra/db.hh
+++ b/src/libhydra/db.hh
@@ -2,7 +2,6 @@
 
 #include <pqxx/pqxx>
 
-#include "environment-variables.hh"
 #include "util.hh"
 
 
diff --git a/src/libhydra/hydra-config.hh b/src/libhydra/hydra-config.hh
index b1275896..1688c278 100644
--- a/src/libhydra/hydra-config.hh
+++ b/src/libhydra/hydra-config.hh
@@ -2,7 +2,6 @@
 
 #include <map>
 
-#include "file-system.hh"
 #include "util.hh"
 
 struct HydraConfig