backflip

#!/bin/bash

# ==============================================================================
#          *** BackFLiP (a.k.a  BACKporting Fun with LInaro People) ***
#
# Usage: backflip rev_number
# ==============================================================================

# ==============================================================================
# Configuration
# ==============================================================================
VERSION=4.9
LINARO_REF_BRANCH=linaro-${VERSION}-branch

DATE=`date +%Y-%m-%d`
NAME=`git config user.name`
EMAIL=`git config user.email`
EDITOR="${EDITOR:-vim}"

# Style 
NC='\e[0m'
red='\e[0;31m'
blue='\e[1;34m'
green='\e[0;32m'
bold='\e[1m'
lines=`perl -E 'say "-" x 80'`

# ==============================================================================
# Functions
# ==============================================================================
print_step() {
  echo -e "${blue}${lines}\n${red}** ${1}\n${blue}${lines}${NC}\n"
}

print_info() {
  echo -e "${blue}** ${NC}${1}"
}

# arg1 : a sentence
# arg2 : a variable
# print arg1 and gather user input in arg2
ask() {
  echo -n -e "${blue}** ${NC}${1} ${NC}"
  eval "read ${2}"
}

# arg1 : svn rev number
# arg2 : ChangeLog file
# Create ChangeLog entry for arg1 in arg2.bcp
forge_entry() {
  echo -e $DATE"  "$NAME"  <"$EMAIL">\n\n\tBackport from trunk r"$1"." >> $2.bcp
  git show --format=oneline ${SHA1} -- $2 \
    | grep ^+ \
    | sed -e '1d' -e 's:^+::' \
    | awk '$1 ~ /^2.*$/ {print "\t"$0}  $1 !~ /^2.*$/ {print $0}' >> $2.bcp
  print_info "${bold}Forged ChangeLog entry:${NC}"
  cat $2.bcp
  ask "${bold}Editing [N/y] ?" user_edit
  if [ "$user_edit" == "y" ]; then
    "$EDITOR" $2.bcp
  fi
}

# ==============================================================================
print_step "Finding SHA1"
# ==============================================================================
SHA1=`git log --format=format:"%H" --grep=trunk@${1} master`
print_info "${NC}SVN rev ${bold}${1}${NC} SHA1: ${bold}${SHA1}${NC}"
ask "${bold}Watch the commit [N/y] ?" user_watch
if [ "$user_watch" == "y" ]; then
   git show $SHA1
fi

# ==============================================================================
print_step "Cherry-picking Revision"
# ==============================================================================
git checkout $LINARO_REF_BRANCH
git cherry-pick -n $SHA1

# ==============================================================================
print_step "Handling ChangeLogs Conflicts"
# ==============================================================================
CHLOGS=`git diff-tree --no-commit-id --name-only -r ${SHA1} | grep ChangeLog`
for i in $CHLOGS; do
  print_info "${green}$i"
  # Revert ChangeLog corruption
  git reset -q HEAD $i
  git checkout $i
  # Create ChangeLog entry
  forge_entry $1 $i
  # Add it in Linaro ChangeLog
  cat $i.linaro >> $i.bcp
  mv $i.bcp $i.linaro
  git add $i.linaro
done

# ==============================================================================
print_step "Status Checking"
# ==============================================================================
git status
ask "${bold}Open a Shell [N/y] ?" user_shell
if [ "$user_shell" == "y" ]; then
   PROMPT_COMMAND="echo -n -e '${bold}[${red}BackFLiP${NC}${bold}]${NC} '" bash 
fi

# ==============================================================================
print_step "Branch/Commit/Push/Review"
# ==============================================================================
bname=${VERSION}-backport-${1}
ask "${bold}Create backport branch [Y/n] ?" user_bc
if [ "$user_bc" != "n" ]; then
  ask "${bold}Change name (${blue}${bname}${NC}${bold}) [N/y] ?" user_bname
  if [ "$user_bname" == "y" ]; then
    ask "${bold}Enter name :" bname
  fi
  git checkout -b ${bname} origin/${LINARO_REF_BRANCH}

  ask "${bold}Commit backport [Y/n] ?" user_commit
  if [ "$user_commit" != "n" ]; then
    git commit

    ask "${bold}Create patch [Y/n] ?" user_patch
    if [ "$user_patch" != "n" ]; then
      git format-patch -o ../ --suffix=.${bname}.patch -1
    fi

    ask "${bold}Push ${bname} branch [Y/n] ?" user_push
    if [ "$user_push" != "n" ]; then
      git push origin ${bname}:${bname}

      ask "${bold}Request review (amend commit) [Y/n] ?" user_review
      if [ "$user_review" != "n" ]; then
        git commit --amend
        git review $LINARO_REF_BRANCH
        git checkout $LINARO_REF_BRANCH
      fi
    fi
  fi
fi

# ==============================================================================
ask "${bold}Abort and Cleanup [N/y] ?" user_abort
# ==============================================================================
if [ "$user_abort" == "y" ]; then
  git reset --hard
  git checkout ${LINARO_REF_BRANCH}
  if [ "$user_bc" != "n" ]; then
    git branch -D ${bname}
    if [ "$user_push" != "n" ]; then
      git push origin :${bname}
    fi
  fi
  exit 0
fi