Checks for PHP syntax errors in a git pre-commit hook

php-syntax-pre-commit.sh

#!/bin/bash

# Load the PHP environment so we can use php.
source /opt/remi/php72/enable

if [ -z "$PHP_BIN" ]
then
    PHP_BIN=php
fi

if [ "$(echo -e test)" = test ]
then
    echo_e="echo -e"
else
    echo_e="echo"
fi

# necessary check for initial commit
if git rev-parse --verify HEAD >/dev/null 2>&1
then
    against=HEAD
else
      # Initial commit: diff against an empty tree object
    against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

errors=""
if ! which "$PHP_BIN" >/dev/null 2>&1
then
    echo "PHP Syntax check failed:"
    echo "PHP binary does not exist or is not in path: $PHP_BIN"
    exit 1
fi

# dash does not support $'\n':
# http://forum.soft32.com/linux2/Bug-409179-DASH-Settings-IFS-work-properly-ftopict70039.html
IFS='
'
# get a list of staged files
for line in $(git diff-index --cached --full-index $against)
do
    # split needed values
    sha=$(echo $line | cut -d' ' -f4)
    temp=$(echo $line | cut -d' ' -f5)
    status=$(echo $temp | cut -d' ' -f1)
    filename=$(echo $temp | cut -d' ' -f2)

    # file extension
    ext=$(echo $filename | sed 's/^.*\.//')

    # only check files with php extension
    if [ "$ext" != "php" ]
    then
            continue
    fi

    # do not check deleted files
    if [ "$status" = "D" ]
    then
            continue
    fi

    # check the staged file content for syntax errors
    # using php -l (lint)
    result=$(git cat-file -p $sha | "$PHP_BIN" -n -l -ddisplay_errors\=1 -derror_reporting\=E_ALL -dlog_errrors\=0 2>&1)
    if [ $? -ne 0 ]
    then
        # Swap back in correct filenames
        errors=$(echo "$errors"; echo "$result" | grep ':' | sed -e "s@in Standard input code on@in $filename on@g")
    fi
done
unset IFS

if [ -n "$errors" ]
then
        echo "!! PHP Syntax check failed !!"
        $echo_e "$errors"
        echo ""
        exit 1
fi