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, 9 insertions, 3 deletions

diff --git a/third_party/nix/src/libexpr/primops/fetchGit.cc b/third_party/nix/src/libexpr/primops/fetchGit.cc
index 7fbd4dc92cf0..818a475f5ecd 100644
--- a/third_party/nix/src/libexpr/primops/fetchGit.cc
+++ b/third_party/nix/src/libexpr/primops/fetchGit.cc
@@ -37,7 +37,9 @@ GitInfo exportGit(ref<Store> store, const std::string& uri,
       runProgram("git", true,
                  {"-C", uri, "diff-index", "--quiet", "HEAD", "--"});
     } catch (ExecError& e) {
-      if (!WIFEXITED(e.status) || WEXITSTATUS(e.status) != 1) throw;
+      if (!WIFEXITED(e.status) || WEXITSTATUS(e.status) != 1) {
+        throw;
+      }
       clean = false;
     }
 
@@ -78,7 +80,9 @@ GitInfo exportGit(ref<Store> store, const std::string& uri,
     ref = "HEAD"s;
   }
 
-  if (!ref) ref = "HEAD"s;
+  if (!ref) {
+    ref = "HEAD"s;
+  }
 
   if (rev != "" && !std::regex_match(rev, revRegex))
     throw Error("invalid Git revision '%s'", rev);
@@ -166,7 +170,9 @@ GitInfo exportGit(ref<Store> store, const std::string& uri,
     }
 
   } catch (SysError& e) {
-    if (e.errNo != ENOENT) throw;
+    if (e.errNo != ENOENT) {
+      throw;
+    }
   }
 
   // FIXME: should pipe this, or find some better way to extract a