[pre-commit] Check ocamlformat version and silence ocamlformat.

Cf. #12049.

1 files changed, 11 insertions, 2 deletions

diff --git a/dev/tools/pre-commit b/dev/tools/pre-commit
index 633913aac6..448e224f2e 100755
--- a/dev/tools/pre-commit
+++ b/dev/tools/pre-commit
@@ -16,6 +16,15 @@ then
     1>&2 echo "Warning: ocamlformat is not in path. Cannot check formatting."
 fi
 
+# Verify that the version of ocamlformat matches the one in .ocamlformat
+# The following command will print an error message if that's not the case
+# (and will print nothing if the versions match)
+if ! echo "let () = ()" | "$ocamlformat" --impl - > /dev/null
+then
+    1>&2 echo "Warning: Cannot check formatting."
+    ocamlformat=true
+fi
+
 1>&2 echo "Auto fixing whitespace and formatting issues..."
 
 # We fix whitespace in the index and in the working tree
@@ -43,7 +52,7 @@ if [ -s "$index" ]; then
     git apply --cached --whitespace=fix "$index"
     git apply --whitespace=fix "$index" 2>/dev/null # no need to repeat yourself
     git diff --cached --name-only -z | xargs -0 dev/tools/check-eof-newline.sh --fix
-    git diff --cached --name-only -z | grep -E '.*\.mli?$' -z | xargs -0 "$ocamlformat" -i || true
+    { git diff --cached --name-only -z | grep -E '.*\.mli?$' -z | xargs -0 "$ocamlformat" -i || true; } 2> /dev/null
     git add -u
     1>&2 echo #newline
 fi
@@ -59,7 +68,7 @@ if [ -s "$tree" ]; then
     1>&2 echo "Fixing unstaged changes..."
     git apply --whitespace=fix "$tree"
     git diff --name-only -z | xargs -0 dev/tools/check-eof-newline.sh --fix
-    git diff --name-only -z | grep -E '.*\.mli?$' -z | xargs -0 "$ocamlformat" -i || true
+    { git diff --name-only -z | grep -E '.*\.mli?$' -z | xargs -0 "$ocamlformat" -i || true; } 2> /dev/null
     1>&2 echo #newline
 fi