Add `treefmt` `pre-commit` hook

This lets us use different formatters for different filetypes.

Change-Id: Ib52383dd5097c8919a65e299aca2b5a55412223c

2 files changed, 5 insertions, 0 deletions

diff --git a/flake.nix b/flake.nix
index be163e386..70b83c251 100644
--- a/flake.nix
+++ b/flake.nix
@@ -331,6 +331,10 @@
               stages = [ "commit" ];
               excludes = [ "^tests/functional/lang/" ];
             };
+            treefmt = {
+              enable = true;
+              settings.formatters = [ ];
+            };
           };
         }) pre-commit-hooks.lib;
       };
diff --git a/treefmt.toml b/treefmt.toml
new file mode 100644
index 000000000..81df72cc2
--- /dev/null
+++ b/treefmt.toml
@@ -0,0 +1 @@
+[formatter]