Make pre-commit execute linter only if php files have been staged

.github/contrib/pre-commit

@@ -1,8 +1,12 @@
 #!/bin/sh
 
+RED=`tput setaf 1`
+RESET=`tput sgr0`
+
 PHP_BINARY=`which php`
-STAGED_FILES_CMD=`git diff --cached --name-only --diff-filter=ACMR HEAD | grep \\\\.php`
+STAGED_FILES_CMD=`git diff --cached --name-only --diff-filter=ACMR HEAD | grep '\.php$'`
 PROJECT_PATH=$(cd "$( dirname "$0" )/../../" && pwd)
+CS_FIXER="./vendor/bin/php-cs-fixer fix"
 
 # Determine if a file list is passed
 if [ "$#" -eq 1 ]
@@ -15,19 +19,35 @@ then
 fi
 SFILES=${SFILES:-$STAGED_FILES_CMD}
 
+if [ -n "$SFILES" ]
+then
+  echo "Checking PHP Lint..."
+  for FILE in $SFILES
+  do
+    $PHP_BINARY -l -d display_errors=0 $PROJECT_PATH/$FILE
+    if [ $? != 0 ]
+    then
+      echo "Error(s), please fix it before commit."
+      exit 1
+    fi
+  done
+
+  echo "Running PHP CS Fixer..."
+
+  $PHP_BINARY $CS_FIXER --dry-run
 
-echo "Checking PHP Lint..."
-for FILE in $SFILES
-do
-  $PHP_BINARY -l -d display_errors=0 $PROJECT_PATH/$FILE
   if [ $? != 0 ]
   then
-    echo "Error(s), please fix it before commit."
-    exit 1
-  fi
-done
+    printf "\n${RED}Some files need to be fixed!${RESET}\n\n"
+    echo "Please run the following script to fix them. Afterwards, add the changed files and commit again:"
+    echo "
+
+    php $CS_FIXER
 
-echo "Running PHP CS Fixer..."
-$PHP_BINARY ./vendor/bin/php-cs-fixer fix
+    "
+    exit 2
+  fi
 
-exit $?
+else
+  echo "No modified PHP files to check."
+fi