path: root/backflip

#!/bin/bash

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

# ==============================================================================
# Configuration
# ==============================================================================
VERSION=6
REF_BRANCH=linaro-local/gcc-${VERSION}-integration-branch

DATE=`date +%Y-%m-%d`
NAME=`git config user.name`
FNAME=`echo ${NAME} | cut -d ' ' -f 1`
EMAIL=`git config user.email`
EDITOR="${EDITOR:-vim}"
STACKED=false
CMPTOOL="meld"
INTERACTIVE=true
COLOR=true
TMPDIR=/tmp/$(basename "$0")-$$
PREFIX=${TMPDIR}/backport

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

# ==============================================================================
# Functions
# ==============================================================================
usage() {
  tool="$(basename "$0")"
  echo -e "$tool [-v GCC_VERSION] [-r REF_BRANCH] [-b DEV_BRANCH] [-x] REVISION"
}

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

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

die() {
  echo -e "${red}${bold}ERROR: ${NC}${bold}${1}${NC}"
  exit 1
}

open_shell() {
  PROMPT_COMMAND="echo -n -e '${bold}[${red}BackFLiP${NC}${bold}]${NC} '" bash
}

# 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.arg1.frag
forge_entry() {
  FRAGFILE=${TMPDIR}/$(echo $2 | sed "s:/:-:g")-$1.frag
  echo -e "\t"`dirname $2`/ >> ${PREFIX}.msg
  echo -e "\tBackport from trunk r$1." >> ${PREFIX}.msg
  git show --format=oneline ${SHA1} -- $2 \
    | grep ^+ \
    | sed -e '1d' -e 's:^+::' \
    | awk '$1 ~ /^2.*$/ {print "\t"$0}  $1 !~ /^2.*$/ {print $0}' > $FRAGFILE

  # Try to fix ChangeLog format frequent issue when the same contributor
  # commits 2 patches in a row.  Git diff messes up with the context and the
  # regular first 2 lines of the entry (DATE  NAME  MAIL\n\n) ended at the
  # bottom of the patch.
  if ! head -n 1 $FRAGFILE | grep "<.*@.*>" \
     && tail -n 2 $FRAGFILE | grep "<.*@.*>" > /dev/null; then
    tail -n 2 $FRAGFILE > ${FRAGFILE}.tmp
    head -n -2 $FRAGFILE >> ${FRAGFILE}.tmp
    mv ${FRAGFILE}.tmp $FRAGFILE
  fi
  print_info "${bold}Forged ChangeLog entry:${NC}"
  cat $FRAGFILE
  if $INTERACTIVE; then
    ask "${bold}Edit ChangeLog entry [N/y] ?" user_edit
    if [ "$user_edit" == "y" ]; then
      "$EDITOR" $FRAGFILE
    fi
  fi
  cat $FRAGFILE >> ${PREFIX}.msg
}

# arg1 : backported revision sha1
compare() {
  git show $1 > ${TMPDIR}/$REV.orig
  git diff --cached > ${TMPDIR}/$REV.linaro
  print_info "Generated diff files: ${bold}$REV.orig $REV.linaro${NC}"
  "$CMPTOOL" ${TMPDIR}/$REV.orig ${TMPDIR}/$REV.linaro
  ask "${bold}Do you need a Shell [N/y] ?" user_shell
  if [ "$user_shell" == "y" ]; then
     open_shell
  fi
}

clean() {
  git reset --hard
  git checkout ${REF_BRANCH}
  if [ $1 -ne 0 ]; then
    echo -e "\n${lines}"
    echo -e "INTERACTIVE MODE COMMAND LINE TO REPRODUCE AND/OR FIX THE ISSUE:"
    echo -e "$0 -v $VERSION -b $DEV_BRANCH -r $REF_BRANCH $RARGS"
    echo -e "${lines}"

    if ! $INTERACTIVE; then
	exec 1>&3 2>&4
	echo -e "Failed to backport rev $REV"
    fi
  fi
  exit $1
}

# Arguments
while getopts ":b:r:v:x" options
do
  case $options in
    r ) REF_BRANCH=$OPTARG
    ;;
    b ) DEV_BRANCH=$OPTARG
	STACKED=true
    ;;
    v ) VERSION=$OPTARG
	REF_BRANCH=linaro-local/gcc-${VERSION}-integration-branch
    ;;
    x ) INTERACTIVE=false
        COLOR=false
    ;;
    \?) print_info "Option -${bold}$OPTARG${NC} Unsupported."
        exit 1
    ;;
    : ) print_info "Option -${bold}$OPTARG${NC} requires an argument."
        usage
        exit 1
    ;;
  esac
done

if [ $# -lt 1 ]; then
    usage ; exit 1
fi

shift $(($OPTIND - 1))

if [ -z ${DEV_BRANCH+x} ]; then
  DEV_BRANCH=${REF_BRANCH}
fi

# ==============================================================================
# Checking Configuration
# ==============================================================================
if ! git remote -v 2>&1 | grep "ssh.*review\.linaro\.org" > /dev/null ; then
  die "You're not in the right directory !"
fi
if [ ! -e .gitreview ]; then
  print_info "Gerrit configuration (.gitreview) is missing, creating it."
  cat <<- EOF > .gitreview
[gerrit]
host=review.linaro.org
port=29418
project=toolchain/gcc
EOF
fi
if $INTERACTIVE; then
  if ! which $CMPTOOL > /dev/null ; then
    print_info "Default comparison tool is missing"
    ask "Enter tool name: " CMPTOOL
  fi
fi

if ! $INTERACTIVE; then
   exec 3>&1 4>&2
fi

# ==============================================================================
# Check that all the requested backports are available
# ==============================================================================
for REV in "$@"
do
  SHA1=`git log --format=format:"%H" --grep=trunk@${REV} master`
  if [ -z "$SHA1" ]; then
    die "${red}Revision ${REV} is missing in master history${NC}"
  fi
done

mkdir $TMPDIR

# ------------------------------------------------------------------------------
for REV in "$@"; do   # Beginning of Stacked Backport Loop
# ------------------------------------------------------------------------------
# Keep remaining args for error messages
RARGS=$@
shift

PREFIX=${PREFIX}-${REV}

if [ -n "${PREV}" ]; then
  STACKED=true
  DEV_BRANCH=$bname
fi

if ! $INTERACTIVE; then
   exec >${PREFIX}.log 2>&1
fi

echo -e "${blue}${lines}"
print_info "Backport will de done on top of branch: ${bold}$DEV_BRANCH${NC}"
print_info "Reference branch used for review is: ${bold}$REF_BRANCH${NC}"
print_info "To change GCC version in a Linaro branch use ${bold}-v${NC}"
print_info "example: ${bold}backflip -v 4.8${NC}"
print_info "To change reference branch use ${bold}-r${NC}"
print_info "example: ${bold}backflip -r master${NC}"

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

# ==============================================================================
print_step "Cherry-picking Revision"
# ==============================================================================
git checkout $DEV_BRANCH
if [ $? -ne 0 ]; then
  print_info "Cannot checkout $DEV_BRANCH branch"
  clean 1
fi
git cherry-pick -n $SHA1 2>/dev/null

# ==============================================================================
print_step "Handling ChangeLogs Conflicts"
# ==============================================================================
CHLOGS=`git diff-tree --no-commit-id --name-only -r ${SHA1} | grep ChangeLog`
# For stacked backports reuse the previous commit message.
PMSG=`find ${TMPDIR} -name \*.msg`
if [ -n "$PMSG" ]; then
  mv $PMSG ${PREFIX}.msg
fi
if [ -z "$CHLOGS" ]; then
  print_info "${red}WARNING: No ChangeLog in this commit.${NC}"
  forge_entry $REV "missing/ChangeLog"
else
  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 $REV $i
  done
fi

# ==============================================================================
print_step "Status Checking"
# ==============================================================================
git status
if $INTERACTIVE; then
  ask "${bold}Open a Shell [N/y] ?" user_shell
  if [ "$user_shell" == "y" ]; then
   open_shell
  fi
else
  git status --porcelain | grep "^.U" && \
                           { mv ${PREFIX}.log ${PREFIX}-ko.log; clean 1; }
  # Avoid creating branches and review request for empty modification
  # (like ChangeLog fixes) but it can be needed for stacked backports.
  if ! $STACKED && git diff --cached --quiet; then
    print_info "Nothing to commit"
    mv ${PREFIX}.log ${PREFIX}-empty.log;
    clean 1
  fi
fi

# ==============================================================================
print_step "Verification"
# ==============================================================================
if $INTERACTIVE; then
  compare $SHA1
else
  print_info "None in batch mode."
fi

# ==============================================================================
print_step "Branch/Commit"
# ==============================================================================
if $STACKED; then
  bname=${DEV_BRANCH}-${REV}
else
  bname=${FNAME}-${VERSION}-backport-${REV}
fi

if $INTERACTIVE; then
  ask "${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} ${DEV_BRANCH}

    ask "${bold}Commit backport [Y/n] ?" user_commit
    if [ "$user_commit" != "n" ]; then
      if $STACKED; then
        git commit --amend -F ${PREFIX}.msg
      else
        git commit -F ${PREFIX}.msg
      fi

      echo
      print_info "If you want to stack another backport on top of this one"
      print_info "you can stop here, and invoke backflip with command:"
      print_info "${bold}backflip -b ${bname} REV_NUMBER${NC}"
      print_info "The next steps are only needed for review and validation.\n"

      ask "${bold}Create patch [Y/n] ?" user_patch
      if [ "$user_patch" != "n" ]; then
        git format-patch -o ../ --suffix=.${bname}.patch -1
      fi
    fi
  fi
else
  print_info "Create backport branch."
  git checkout -b ${bname} ${DEV_BRANCH}
  if [ $? -ne 0 ]; then
    print_info "Cannot checkout $DEV_BRANCH branch"
    clean 1
  fi
  print_info "Commit backport."
  if $STACKED; then
    git commit --amend -F ${PREFIX}.msg
  else
    git commit -F ${PREFIX}.msg
  fi
fi

PREV=$REV
# ------------------------------------------------------------------------------
done   # End of stacked backport loop
# ------------------------------------------------------------------------------

# ==============================================================================
print_step "Review"
# ==============================================================================
if $INTERACTIVE; then
    if [ "$user_commit" != "n" ]; then
      ask "${bold}Request review [Y/n] ?" user_review
      if [ "$user_review" != "n" ]; then
        git review $REF_BRANCH
      fi
    fi
else
  print_info "Request review."
  #git review $REF_BRANCH
  if [ $? -ne 0 ]; then
    print_info "Cannot request review"
    clean 1
  fi
fi

# ==============================================================================
print_step "Cleanup"
# ==============================================================================
clean 0