Allow shorter syntax for chroot stores

You can now say '--store /tmp/nix' instead of '--store local?root=/tmp/nix'.

src/build-remote/build-remote.cc

@@ -176,9 +176,13 @@ int main (int argc, char * * argv)
 
                     Activity act(*logger, lvlTalkative, actUnknown, fmt("connecting to '%s'", bestMachine->storeUri));
 
-                    Store::Params storeParams{{"max-connections", "1"}, {"log-fd", "4"}};
+                    Store::Params storeParams;
+                    if (hasPrefix(storeUri, "ssh://")) {
+                        storeParams["max-connections"] ="1";
+                        storeParams["log-fd"] = "4";
                         if (bestMachine->sshKey != "")
                             storeParams["ssh-key"] = bestMachine->sshKey;
+                    }
 
                     sshStore = openStore(bestMachine->storeUri, storeParams);
                     sshStore->connect();

src/libstore/machines.cc

@@ -17,7 +17,11 @@ Machine::Machine(decltype(storeUri) storeUri,
     storeUri(
         // Backwards compatibility: if the URI is a hostname,
         // prepend ssh://.
-        storeUri.find("://") != std::string::npos || hasPrefix(storeUri, "local") || hasPrefix(storeUri, "remote") || hasPrefix(storeUri, "auto")
+        storeUri.find("://") != std::string::npos
+        || hasPrefix(storeUri, "local")
+        || hasPrefix(storeUri, "remote")
+        || hasPrefix(storeUri, "auto")
+        || hasPrefix(storeUri, "/")
         ? storeUri
         : "ssh://" + storeUri),
     systemTypes(systemTypes),

src/libstore/store-api.cc

@@ -843,7 +843,7 @@ StoreType getStoreType(const std::string & uri, const std::string & stateDir)
 {
     if (uri == "daemon") {
         return tDaemon;
-    } else if (uri == "local") {
+    } else if (uri == "local" || hasPrefix(uri, "/")) {
         return tLocal;
     } else if (uri == "" || uri == "auto") {
         if (access(stateDir.c_str(), R_OK | W_OK) == 0)
@@ -865,8 +865,12 @@ static RegisterStoreImplementation regStore([](
     switch (getStoreType(uri, get(params, "state", settings.nixStateDir))) {
         case tDaemon:
             return std::shared_ptr<Store>(std::make_shared<UDSRemoteStore>(params));
-        case tLocal:
+        case tLocal: {
-            return std::shared_ptr<Store>(std::make_shared<LocalStore>(params));
+            Store::Params params2 = params;
+            if (hasPrefix(uri, "/"))
+                params2["root"] = uri;
+            return std::shared_ptr<Store>(std::make_shared<LocalStore>(params2));
+        }
         default:
             return nullptr;
     }

tests/build-remote.sh

@@ -11,7 +11,7 @@ rm -rf $TEST_ROOT/store0 $TEST_ROOT/store1
 
 nix build -f build-hook.nix -o $TEST_ROOT/result --max-jobs 0 \
   --sandbox-paths /nix/store --sandbox-build-dir /build-tmp \
-  --builders "local?root=$TEST_ROOT/store0; local?root=$TEST_ROOT/store1 - - 1 1 foo"
+  --builders "$TEST_ROOT/store0; $TEST_ROOT/store1 - - 1 1 foo"
 
 outPath=$TEST_ROOT/result
 
@@ -19,5 +19,5 @@ cat $outPath/foobar | grep FOOBAR
 
 # Ensure that input1 was built on store1 due to the required feature.
 p=$(readlink -f $outPath/input-2)
-(! nix path-info --store local?root=$TEST_ROOT/store0 --all | grep dependencies.builder1.sh)
+(! nix path-info --store $TEST_ROOT/store0 --all | grep dependencies.builder1.sh)
-nix path-info --store local?root=$TEST_ROOT/store1 --all | grep dependencies.builder1.sh
+nix path-info --store $TEST_ROOT/store1 --all | grep dependencies.builder1.sh

tests/linux-sandbox.sh

@@ -14,7 +14,7 @@ chmod -R u+w $TEST_ROOT/store0 || true
 rm -rf $TEST_ROOT/store0
 
 export NIX_STORE_DIR=/my/store
-export NIX_REMOTE="local?root=$TEST_ROOT/store0"
+export NIX_REMOTE=$TEST_ROOT/store0
 
 outPath=$(nix-build dependencies.nix --no-out-link --option sandbox-paths /nix/store)