Server-side pre-receive hook to check for merge artefacts such as '<<<<<<<' or '>>>>>>>'

pre-receive-merge

#!/usr/bin/env bash

# pre-receive hook that check for merge artefacts such as '<<<<<<<' or '>>>>>>>'

# Possible improvements : https://gist.github.com/hartfordfive/9670011#gistcomment-2045250

COMMAND="grep -RI '<<<<<<<\|>>>>>>>'"
TEMPDIR=`mktemp -d`

# See https://www.kernel.org/pub/software/scm/git/docs/githooks.html#pre-receive    
oldrev=$1
newrev=$2
refname=$3

while read oldrev newrev refname; do
    
    # Get the file names, without directory, of the files that have been modified
    # between the new revision and the old revision
    files=`git diff --name-only ${oldrev} ${newrev}`

    # Get a list of all objects in the new revision
    objects=`git ls-tree --full-name -r ${newrev}`

    # Iterate over each of these files
    for file in ${files}; do
  
        # Search for the file name in the list of all objects
        object=`echo -e "${objects}" | egrep "(\s)${file}\$" | awk '{ print $3 }'`
        
        # If it's not present, then continue to the the next itteration
        if [ -z ${object} ]; 
	then 
	    continue; 
	fi

        # Otherwise, create all the necessary sub directories in the new temp directory
        mkdir -p "${TEMPDIR}/`dirname ${file}`" &>/dev/null
        # and output the object content into it's original file name
	    git cat-file blob ${object} > ${TEMPDIR}/${file}
	
    done;
done

# Now loop over each file in the temp dir to parse them for valid syntax
files_found=`find ${TEMPDIR} -type f` # -name '*'`
for fname in ${files_found}; do
    result="$(eval "${COMMAND} ${fname} | wc -l")"
    #echo "${result}"
    if [[ "$result" != "0" ]]; then
      name=${fname#$TEMPDIR}
      name=${name#"/"}
 	  echo "************************************************************************" 
 	  echo "** ERROR: Incomplete merge artefacts detected in '${name}'" 
   	  echo "************************************************************************" 
      bad_file=1
    fi
done;

rm -rf ${TEMPDIR} &> /dev/null

if [[ $bad_file -eq 1 ]]
then
  exit 1
fi