Pre-commit git hook helper script

.github/format.sh

@@ -10,7 +10,31 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-FILES_CHANGED=`git diff --name-only origin/master`
+# ----------------------------------------------------------------
+# To use this script as a hook, symlink it to your git hooks as follows:
+# (note that the extra ../../ in the path is because git runs the hook
+# from the .git/hooks directory, so the symlink has to be redirected).
+#
+# cd <project root (primary worktree if using git worktree dir)>
+# ln -s -f ../../.github/format.sh .git/hooks/pre-commit
+# ----------------------------------------------------------------
+
+SCRIPT=`dirname $0`
+if [ "$SCRIPT" == ".git/hooks" ] ; then
+  GIT_HOOK=true
+  FILES_CHANGED=`git diff --cached --name-only --diff-filter=ACMRT`
+  cxxfiles=()
+  cmakefiles=()
+  red=$(tput setaf 1)
+  green=$(tput setaf 2)
+  yellow=$(tput setaf 3)
+  blue=$(tput setaf 4)
+  normal=$(tput sgr0)
+else
+  FILES_CHANGED=`git diff --name-only origin/master`
+fi
+
+CLANG_FORMAT_VERSION=clang-format-15
 TAB_FOUND=0
 
 for FILE in $FILES_CHANGED
@@ -22,16 +46,32 @@ do
 
   case $FILE in
     *.cpp|*.h|*.h.in|*.tpp|*.cu)
-      clang-format-15 -i --style=file $FILE
-      # The following is needed for regions in which clang-format is disabled.
-      # Note: clang-format removes trailing spaces even in disabled regions.
-      # Check if tab are present.
-      egrep -Hn $'\t' $FILE && TAB_FOUND=1 || true
+      if [ "$GIT_HOOK" = true ] ; then
+        if ! cmp -s <(git show :$FILE) <(git show :$FILE|$CLANG_FORMAT_VERSION -style=file); then
+          cxxfiles+=("$FILE")
+        fi
+      else
+        $CLANG_FORMAT_VERSION -i --style=file $FILE
+        # The following is needed for regions in which clang-format is disabled.
+        # Note: clang-format removes trailing spaces even in disabled regions.
+        # Check if tab are present.
+        egrep -Hn $'\t' $FILE && TAB_FOUND=1 || true
+      fi
       ;;
     *.cmake|*CMakeLists.txt|*.cmake.in)
-      cmake-format -i $FILE
-      # Check if tab are present.
-      egrep -Hn $'\t' $FILE && TAB_FOUND=1 || true
+      if [ "$GIT_HOOK" = true ] ; then
+        tmpfile=$(mktemp /tmp/cmake-check.XXXXXX)
+        git show :${file} > $tmpfile
+        cmake-format -c $(pwd)/.cmake-format.py -i $tmpfile
+        if ! cmp -s <(git show :${file}) <(cat $tmpfile); then
+          cmakefiles+=("${file}")
+        fi
+        rm $tmpfile
+      else
+        cmake-format -i $FILE
+        # Check if tab are present.
+        egrep -Hn $'\t' $FILE && TAB_FOUND=1 || true
+      fi
       ;;
     *.pdf|*.hdf5|*.jpg|*.png|*.ppt|*.pptx|*.ipe)
       # Exclude some binary files types,
@@ -56,11 +96,41 @@ do
       ;;
   esac
 done
-# Fail if there are tabs in source files.
-if [ $TAB_FOUND -eq 1 ]
-then
-  echo "Error: Tabs have been found in source files"
-  false
+
+if [ "$GIT_HOOK" = true ] ; then
+  returncode=0
+  full_list=
+  if [ -n "${cxxfiles}" ]; then
+    printf "# ${blue}clang-format ${red}error pre-commit${normal} : To fix run the following (use git commit ${yellow}--no-verify${normal} to bypass)\n"
+    for f in "${cxxfiles[@]}" ; do
+      rel=$(realpath --relative-to "./$GIT_PREFIX" $f)
+      printf "$CLANG_FORMAT_VERSION -i %s\n" "$rel"
+      full_list="${rel} ${full_list}"
+    done
+    returncode=1
+  fi
+
+  if [ -n "${cmakefiles}" ]; then
+    printf "# ${green}cmake-format ${red}error pre-commit${normal} : To fix run the following (use git commit ${yellow}--no-verify${normal} to bypass)\n"
+    for f in "${cmakefiles[@]}" ; do
+      rel=$(realpath --relative-to "./$GIT_PREFIX" $f)
+      printf "cmake-format -i %s\n" "$rel"
+      full_list="${rel} ${full_list}"
+    done
+    returncode=1
+  fi
+
+  if [ ! -z "$full_list" ]; then
+    printf "\n# ${red}To commit the corrected files, run\n${normal}\ngit add ${full_list}\n"
+  fi
+  exit $returncode
 else
-  true
+  # Fail if there are tabs in source files.
+  if [ $TAB_FOUND -eq 1 ]
+  then
+    echo "Error: Tabs have been found in source files"
+    false
+  else
+    true
+  fi
 fi