pre-receive hook on server-side that refuse any push to master which has any non-linear history

Question

I am looking for a shell script (sh, not bash possibly) that would refuse any push to master which has any non-linear history.

I t

Answer 1

This script worked for me! It protects selected branches against forced push and deletes.

#!/bin/sh

_REFNAME="$(echo "${1}" | sed -e 's,[^/]\+/,,g')"
_OLDREF="${2}"
_NEWREF="${3}"

_PROTECTED_LIST=( 'master' 'develop' )

_PROTECTED=false
for ref in "${_PROTECTED_LIST[@]}"; do
   if [[ "${ref}" == "${_REFNAME}" ]]; then
      _PROTECTED=true
   fi;
done;

echo ""
echo "#################### YOUR PROJECT NAME ####################"
echo "Branch: ${_REFNAME}"
echo "Old ref: ${_OLDREF}"
echo "New ref: ${_NEWREF}"
echo ""

_SUCCESS=true
if ${_PROTECTED}; then
   _GITOUT="$(git merge-base ${_OLDREF} ${_NEWREF} 2>/dev/null)"
   if [[ -n "${_GITOUT}" && "${_GITOUT}" != "${_OLDREF}" ]]; then
      echo "ERROR! You can't force the push on this branch!"
      _SUCCESS=false
   fi;
   if [[ -n "$(echo "${_NEWREF}" | sed -n -e '/^0\+$/p')" ]]; then
      echo "ERROR! You can't delete this branch!"
      _SUCCESS=false
   fi;
fi;

if ${_SUCCESS}; then
   echo "SUCCESS! :-)"
   echo "See you later?"
   echo ""
   exit 0
fi;

echo ""
exit 1