php syntax check for git pre-receive hook

pre-receive

#! /bin/bash

errors_buffer=""
working_dir=""

function php_syntax_check() {
    local errors=$(php -l $file 2>&1 | grep "Parse error")
    if [ "$errors" != "" ]; then
        if [ "$errors_buffer" != "" ]; then
            errors_buffer="$errors_buffer\n$errors"
        else
            errors_buffer="$errors"
        fi
        echo "Syntax errors found in file: $file "
    fi
}

function bom_check() {
    if [ "`head -c 3 -- "$file"`" == $'\xef\xbb\xbf' ]; then
        local errors="Found BOM in $file"
        if [ "$errors_buffer" != "" ]; then
            errors_buffer="$errors_buffer\n$errors"
        else
            errors_buffer="$errors"
        fi
    fi
}

function line_ending_check() {
    grep -Hnq $'\r' "$file"; RET=$?
    if [ $RET -ne 1 ]; then
        errors="Windows/Mac newlines found in $file"
        if [ "$errors_buffer" != "" ]; then
            errors_buffer="$errors_buffer\n$errors"
        else
            errors_buffer="$errors"
        fi
    fi
}

while read old_rev new_rev ref_name
do
    zero="0000000000000000000000000000000000000000"
    if [ "$old_rev" = "$zero" ]; then
        # Created new branch
        list=$(git diff-tree -r ${new_rev} | awk '{if ($5 != "D") print $6}')
    elif [ "$new_rev" = "$zero" ]; then
        # Deleted branch
        exit 0
    else
        list=$(git diff-tree -r ${old_rev}..${new_rev} | awk '{if ($5 != "D") print $6}')
    fi

    #echo "DEBUG \$list: $list"
    # if commit not contain php-files -exit
    if [ -z "$list" ]; then
        exit 0
    fi

    working_dir="/tmp/_git_$newrev/"
    mkdir -p $working_dir
    echo $list |\
        xargs git archive --format=tar $new_rev|\
        (cd $working_dir && tar xf -)

    cd $working_dir
    for file in $list
    do
        echo $file

        # Check php syntax
        extension=$(echo "$file" | grep ".php$")
        if [ "$extension" != "" ]; then
            php_syntax_check $file
        fi

        extension=$(echo "$file" | grep -E "(java|js|php|ini|xml|yml|htm|html|tpl|sh|bat|conf|less)$")
        if [ "$extension" != "" ]; then

            # Check BOM
            bom_check $file

            # Check line endings
            line_ending_check $file
        fi
    done
    cd - > /dev/null
    rm -rf $working_dir

    if [ "$errors_buffer" != "" ]; then
        echo
        echo "These errors were found in try-to-push files: "
        echo -e $errors_buffer
        echo
        echo "Can't push, please fix errors first."
        exit 1
    else
        echo "Pushed successfully."
    fi
done