style(3p/nix): Enforce braces around loops and conditionals r/767

This change was generated with:

  fd -e cc -e hh | xargs -I{} clang-tidy {} -p ~/projects/nix-build/ \
    --checks='-*,readability-braces-around-statements' --fix \
    -fix-errors

Some manual fixes were applied because some convoluted unbraced
statements couldn't be untangled by clang-tidy.

This commit still includes invalid files, but I decided to clean them
up in a subsequent commit so that it becomes more obvious where
clang-tidy failed. Maybe this will allow for a bug-report to
clang-tidy.

1 files changed, 3 insertions, 1 deletions

diff --git a/third_party/nix/src/nix-channel/nix-channel.cc b/third_party/nix/src/nix-channel/nix-channel.cc
index 40a3c4464d48..767682c0c30d 100644
--- a/third_party/nix/src/nix-channel/nix-channel.cc
+++ b/third_party/nix/src/nix-channel/nix-channel.cc
@@ -18,7 +18,9 @@ static Path channelsList;
 
 // Reads the list of channels.
 static void readChannels() {
-  if (!pathExists(channelsList)) return;
+  if (!pathExists(channelsList)) {
+    return;
+  }
   auto channelsFile = readFile(channelsList);
 
   for (const auto& line :