remove-modules

#!/bin/sh
#+
#  Name:
#     remove-modules

#  Purpose:
#     Remove git submodules from a working tree.

#  Type of Module:
#     Bourne shell script

#  Usage:
#     remove-modules [-f] [submodule]

#  Description:
#     This script removes the content of the given submodule, or all
#     submodules if ran without any arguments. It is destructive so
#     should be used with care.
#
#     If any submodule contains local changes then this script will refuse
#     to run. You will need to correct the problem that represents before
#     running this script.
#
#     A typical use of this script is to clear out all submodules in a
#     working tree where update-modules has been ran, before switching
#     to an historical release branch. Historical branches contain the
#     original source in place of the submodules (the last of these
#     is lehuakona).
#
#     In extreme circumstances when you do not have any changes to preserve
#     and the submodules are in a mess the "-f" flag can be used to skip all
#     safety checks.

#  Authors:
#     PWD: P.W. Draper (JAC, Durham University)
#     {enter_new_authors_here}

#  Copyright:
#     Copyright (C) 2009 Science and Technology Facilities Council.
#     All Rights Reserved.

#  Licence:
#     This program is free software; you can redistribute it and/or
#     modify it under the terms of the GNU General Public License as
#     published by the Free Software Foundation; either version 2 of the
#     License, or (at your option) any later version.
#
#     This program is distributed in the hope that it will be
#     useful, but WITHOUT ANY WARRANTY; without even the implied warranty
#     of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
#     GNU General Public License for more details.
#
#     You should have received a copy of the GNU General Public License
#     along with this program; if not, write to the Free Software
#     Foundation, Inc., 51 Franklin Street,Fifth Floor, Boston, MA
#     02110-1301, USA

#  History:
#     18-FEB-2009: (PWD):
#        Original version.
#     {enter_further_changes_here}

#-

echo ""
echo "Removing all local repository submodules:"

#  Parse any command-line arguments. We just have two optional ones,
#  -f and a submodule.
check=1
if test "$1" != ""; then
   if test "$1" = "-f"; then
      check=0
      shift
   fi
   submodule="$1"
else
   submodule=""
fi

#  Get a list of all the paths to the submodules or check that the given
#  submodule is valid.
if test "$submodule" = ""; then
   submodule_list="`git ls-files --stage | grep ^160000| awk '{print $4}'`"
else
   submodule_list="$submodule"
   #  Verify this a submodule.
   found="`git ls-files --stage | grep ^160000| grep $submodule| awk '{print $4}'`"
   if test "$found" != "$submodule"; then
      echo "ERROR: no such submodule: ... $submodule"
      exit 1
   fi
fi

#  Get a summary of the submodules. If this returns any content then one or
#  more have been modified and committed and should be pushed or reset before
#  proceeding.

if test "$check" = "1"; then

   summary=`git submodule summary $submodule`

   if test "$summary" != ""; then
      echo "ERROR: submodule(s) are modified, will not remove"
      echo "$summary"
      exit 1
   fi

#  The above will not report modified files that have not been committed.
#  This isn't important, but probably indicates some activity in the
#  submodule so refuse to proceed when they are present as well.

   if test "$check" = "1"; then
      for m in $submodule_list; do

         #  May not be checked in yet, in that case we see the modified files
         #  in the full repository. Avoid that case.
         nfiles=`cd $m && ls -a | wc -w`
         if test $nfiles -gt 2 ; then
            modified=`cd $m && git diff-index --name-status HEAD`
            if test "$modified" != ""; then
               echo "WARNING: submodule contains modified files, will not proceed"
               echo "... $m"
               echo "$modified" | head
               exit 1
            fi
         else
            echo "... found uninitialised submodule: $m"
         fi
      done
   fi
fi

#  No modifications or told to proceed so get on with removal of contents.
#  Since this is destructive, ask one more time.

read -p "Are you sure you want to proceed (y/N)? " answer

if test "$answer" = "y"; then

   for m in $submodule_list; do
      nfiles=`cd $m && ls -a | wc -w`
      if test $nfiles -gt 2 ; then
         rm -rf $m
         mkdir -p $m
         echo "... removed: $m"
      else
         echo "... ignored: $m"
      fi
   done

   echo "Removal complete:"
   git status
   echo ""
else
   echo "Nothing done"
fi
exit