style(3p/nix): Add braces around single-line conditionals r/771

These were not caught by the previous clang-tidy invocation, but were
instead sorted out using amber[0] as such:

    ambr --regex 'if (\(.+\))\s([a-z].*;)' 'if $1 { $2 }'

[0]: https://github.com/dalance/amber

1 files changed, 12 insertions, 4 deletions

diff --git a/third_party/nix/src/nix-env/user-env.cc b/third_party/nix/src/nix-env/user-env.cc
index c35959c532..0719c8a51d 100644
--- a/third_party/nix/src/nix-env/user-env.cc
+++ b/third_party/nix/src/nix-env/user-env.cc
@@ -31,7 +31,9 @@ bool createUserEnv(EvalState& state, DrvInfos& elems, const Path& profile,
      exist already. */
   PathSet drvsToBuild;
   for (auto& i : elems)
-    if (i.queryDrvPath() != "") drvsToBuild.insert(i.queryDrvPath());
+    if (i.queryDrvPath() != "") {
+      drvsToBuild.insert(i.queryDrvPath());
+    }
 
   DLOG(INFO) << "building user environment dependencies";
   state.store->buildPaths(drvsToBuild, state.repair ? bmRepair : bmNormal);
@@ -54,7 +56,9 @@ bool createUserEnv(EvalState& state, DrvInfos& elems, const Path& profile,
     mkString(*state.allocAttr(v, state.sType), "derivation");
     mkString(*state.allocAttr(v, state.sName), i.queryName());
     auto system = i.querySystem();
-    if (!system.empty()) mkString(*state.allocAttr(v, state.sSystem), system);
+    if (!system.empty()) {
+      mkString(*state.allocAttr(v, state.sSystem), system);
+    }
     mkString(*state.allocAttr(v, state.sOutPath), i.queryOutPath());
     if (drvPath != "")
       mkString(*state.allocAttr(v, state.sDrvPath), i.queryDrvPath());
@@ -84,13 +88,17 @@ bool createUserEnv(EvalState& state, DrvInfos& elems, const Path& profile,
     StringSet metaNames = i.queryMetaNames();
     for (auto& j : metaNames) {
       Value* v = i.queryMeta(j);
-      if (!v) continue;
+      if (!v) {
+        continue;
+      }
       vMeta.attrs->push_back(Attr(state.symbols.create(j), v));
     }
     vMeta.attrs->sort();
     v.attrs->sort();
 
-    if (drvPath != "") references.insert(drvPath);
+    if (drvPath != "") {
+      references.insert(drvPath);
+    }
   }
 
   /* Also write a copy of the list of user environment elements to