git/contrib/examples/git-merge.sh
Avery Pennarun 8cc5b29065 git merge -X<option>
Teach "-X <option>" command line argument to "git merge" that is passed to
strategy implementations.  "ours" and "theirs" autoresolution introduced
by the previous commit can be asked to the recursive strategy.

Signed-off-by: Avery Pennarun <apenwarr@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-17 22:45:06 -08:00

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#!/bin/sh
#
# Copyright (c) 2005 Junio C Hamano
#
OPTIONS_KEEPDASHDASH=
OPTIONS_SPEC="\
git merge [options] <remote>...
git merge [options] <msg> HEAD <remote>
--
stat show a diffstat at the end of the merge
n don't show a diffstat at the end of the merge
summary (synonym to --stat)
log add list of one-line log to merge commit message
squash create a single commit instead of doing a merge
commit perform a commit if the merge succeeds (default)
ff allow fast-forward (default)
s,strategy= merge strategy to use
m,message= message to be used for the merge commit (if any)
"
SUBDIRECTORY_OK=Yes
. git-sh-setup
require_work_tree
cd_to_toplevel
test -z "$(git ls-files -u)" ||
die "You are in the middle of a conflicted merge."
LF='
'
all_strategies='recur recursive octopus resolve stupid ours subtree'
all_strategies="$all_strategies recursive-ours recursive-theirs"
default_twohead_strategies='recursive'
default_octopus_strategies='octopus'
no_fast_forward_strategies='subtree ours'
no_trivial_strategies='recursive recur subtree ours recursive-ours recursive-theirs'
use_strategies=
allow_fast_forward=t
allow_trivial_merge=t
squash= no_commit= log_arg=
dropsave() {
rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
"$GIT_DIR/MERGE_STASH" || exit 1
}
savestate() {
# Stash away any local modifications.
git stash create >"$GIT_DIR/MERGE_STASH"
}
restorestate() {
if test -f "$GIT_DIR/MERGE_STASH"
then
git reset --hard $head >/dev/null
git stash apply $(cat "$GIT_DIR/MERGE_STASH")
git update-index --refresh >/dev/null
fi
}
finish_up_to_date () {
case "$squash" in
t)
echo "$1 (nothing to squash)" ;;
'')
echo "$1" ;;
esac
dropsave
}
squash_message () {
echo Squashed commit of the following:
echo
git log --no-merges --pretty=medium ^"$head" $remoteheads
}
finish () {
if test '' = "$2"
then
rlogm="$GIT_REFLOG_ACTION"
else
echo "$2"
rlogm="$GIT_REFLOG_ACTION: $2"
fi
case "$squash" in
t)
echo "Squash commit -- not updating HEAD"
squash_message >"$GIT_DIR/SQUASH_MSG"
;;
'')
case "$merge_msg" in
'')
echo "No merge message -- not updating HEAD"
;;
*)
git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
git gc --auto
;;
esac
;;
esac
case "$1" in
'')
;;
?*)
if test "$show_diffstat" = t
then
# We want color (if set), but no pager
GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
fi
;;
esac
# Run a post-merge hook
if test -x "$GIT_DIR"/hooks/post-merge
then
case "$squash" in
t)
"$GIT_DIR"/hooks/post-merge 1
;;
'')
"$GIT_DIR"/hooks/post-merge 0
;;
esac
fi
}
merge_name () {
remote="$1"
rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
if test "$rh" = "$bh"
then
echo "$rh branch '$remote' of ."
elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
then
echo "$rh branch '$truname' (early part) of ."
elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
then
sed -e 's/ not-for-merge / /' -e 1q \
"$GIT_DIR/FETCH_HEAD"
else
echo "$rh commit '$remote'"
fi
}
parse_config () {
while test $# != 0; do
case "$1" in
-n|--no-stat|--no-summary)
show_diffstat=false ;;
--stat|--summary)
show_diffstat=t ;;
--log|--no-log)
log_arg=$1 ;;
--squash)
test "$allow_fast_forward" = t ||
die "You cannot combine --squash with --no-ff."
squash=t no_commit=t ;;
--no-squash)
squash= no_commit= ;;
--commit)
no_commit= ;;
--no-commit)
no_commit=t ;;
--ff)
allow_fast_forward=t ;;
--no-ff)
test "$squash" != t ||
die "You cannot combine --squash with --no-ff."
allow_fast_forward=f ;;
-s|--strategy)
shift
case " $all_strategies " in
*" $1 "*)
use_strategies="$use_strategies$1 " ;;
*)
die "available strategies are: $all_strategies" ;;
esac
;;
-m|--message)
shift
merge_msg="$1"
have_message=t
;;
--)
shift
break ;;
*) usage ;;
esac
shift
done
args_left=$#
}
test $# != 0 || usage
have_message=
if branch=$(git-symbolic-ref -q HEAD)
then
mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
if test -n "$mergeopts"
then
parse_config $mergeopts --
fi
fi
parse_config "$@"
while test $args_left -lt $#; do shift; done
if test -z "$show_diffstat"; then
test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
test "$(git config --bool merge.stat)" = false && show_diffstat=false
test -z "$show_diffstat" && show_diffstat=t
fi
# This could be traditional "merge <msg> HEAD <commit>..." and the
# way we can tell it is to see if the second token is HEAD, but some
# people might have misused the interface and used a committish that
# is the same as HEAD there instead. Traditional format never would
# have "-m" so it is an additional safety measure to check for it.
if test -z "$have_message" &&
second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
test "$second_token" = "$head_commit"
then
merge_msg="$1"
shift
head_arg="$1"
shift
elif ! git rev-parse --verify HEAD >/dev/null 2>&1
then
# If the merged head is a valid one there is no reason to
# forbid "git merge" into a branch yet to be born. We do
# the same for "git pull".
if test 1 -ne $#
then
echo >&2 "Can merge only exactly one commit into empty head"
exit 1
fi
rh=$(git rev-parse --verify "$1^0") ||
die "$1 - not something we can merge"
git update-ref -m "initial pull" HEAD "$rh" "" &&
git read-tree --reset -u HEAD
exit
else
# We are invoked directly as the first-class UI.
head_arg=HEAD
# All the rest are the commits being merged; prepare
# the standard merge summary message to be appended to
# the given message. If remote is invalid we will die
# later in the common codepath so we discard the error
# in this loop.
merge_name=$(for remote
do
merge_name "$remote"
done | git fmt-merge-msg $log_arg
)
merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
fi
head=$(git rev-parse --verify "$head_arg"^0) || usage
# All the rest are remote heads
test "$#" = 0 && usage ;# we need at least one remote head.
set_reflog_action "merge $*"
remoteheads=
for remote
do
remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
die "$remote - not something we can merge"
remoteheads="${remoteheads}$remotehead "
eval GITHEAD_$remotehead='"$remote"'
export GITHEAD_$remotehead
done
set x $remoteheads ; shift
case "$use_strategies" in
'')
case "$#" in
1)
var="`git config --get pull.twohead`"
if test -n "$var"
then
use_strategies="$var"
else
use_strategies="$default_twohead_strategies"
fi ;;
*)
var="`git config --get pull.octopus`"
if test -n "$var"
then
use_strategies="$var"
else
use_strategies="$default_octopus_strategies"
fi ;;
esac
;;
esac
for s in $use_strategies
do
for ss in $no_fast_forward_strategies
do
case " $s " in
*" $ss "*)
allow_fast_forward=f
break
;;
esac
done
for ss in $no_trivial_strategies
do
case " $s " in
*" $ss "*)
allow_trivial_merge=f
break
;;
esac
done
done
case "$#" in
1)
common=$(git merge-base --all $head "$@")
;;
*)
common=$(git show-branch --merge-base $head "$@")
;;
esac
echo "$head" >"$GIT_DIR/ORIG_HEAD"
case "$allow_fast_forward,$#,$common,$no_commit" in
?,*,'',*)
# No common ancestors found. We need a real merge.
;;
?,1,"$1",*)
# If head can reach all the merge then we are up to date.
# but first the most common case of merging one remote.
finish_up_to_date "Already up-to-date."
exit 0
;;
t,1,"$head",*)
# Again the most common case of merging one remote.
echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
git update-index --refresh 2>/dev/null
msg="Fast-forward"
if test -n "$have_message"
then
msg="$msg (no commit created; -m option ignored)"
fi
new_head=$(git rev-parse --verify "$1^0") &&
git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
finish "$new_head" "$msg" || exit
dropsave
exit 0
;;
?,1,?*"$LF"?*,*)
# We are not doing octopus and not fast-forward. Need a
# real merge.
;;
?,1,*,)
# We are not doing octopus, not fast-forward, and have only
# one common.
git update-index --refresh 2>/dev/null
case "$allow_trivial_merge" in
t)
# See if it is really trivial.
git var GIT_COMMITTER_IDENT >/dev/null || exit
echo "Trying really trivial in-index merge..."
if git read-tree --trivial -m -u -v $common $head "$1" &&
result_tree=$(git write-tree)
then
echo "Wonderful."
result_commit=$(
printf '%s\n' "$merge_msg" |
git commit-tree $result_tree -p HEAD -p "$1"
) || exit
finish "$result_commit" "In-index merge"
dropsave
exit 0
fi
echo "Nope."
esac
;;
*)
# An octopus. If we can reach all the remote we are up to date.
up_to_date=t
for remote
do
common_one=$(git merge-base --all $head $remote)
if test "$common_one" != "$remote"
then
up_to_date=f
break
fi
done
if test "$up_to_date" = t
then
finish_up_to_date "Already up-to-date. Yeeah!"
exit 0
fi
;;
esac
# We are going to make a new commit.
git var GIT_COMMITTER_IDENT >/dev/null || exit
# At this point, we need a real merge. No matter what strategy
# we use, it would operate on the index, possibly affecting the
# working tree, and when resolved cleanly, have the desired tree
# in the index -- this means that the index must be in sync with
# the $head commit. The strategies are responsible to ensure this.
case "$use_strategies" in
?*' '?*)
# Stash away the local changes so that we can try more than one.
savestate
single_strategy=no
;;
*)
rm -f "$GIT_DIR/MERGE_STASH"
single_strategy=yes
;;
esac
result_tree= best_cnt=-1 best_strategy= wt_strategy=
merge_was_ok=
for strategy in $use_strategies
do
test "$wt_strategy" = '' || {
echo "Rewinding the tree to pristine..."
restorestate
}
case "$single_strategy" in
no)
echo "Trying merge strategy $strategy..."
;;
esac
# Remember which strategy left the state in the working tree
wt_strategy=$strategy
git-merge-$strategy $common -- "$head_arg" "$@"
exit=$?
if test "$no_commit" = t && test "$exit" = 0
then
merge_was_ok=t
exit=1 ;# pretend it left conflicts.
fi
test "$exit" = 0 || {
# The backend exits with 1 when conflicts are left to be resolved,
# with 2 when it does not handle the given merge at all.
if test "$exit" -eq 1
then
cnt=`{
git diff-files --name-only
git ls-files --unmerged
} | wc -l`
if test $best_cnt -le 0 -o $cnt -le $best_cnt
then
best_strategy=$strategy
best_cnt=$cnt
fi
fi
continue
}
# Automerge succeeded.
result_tree=$(git write-tree) && break
done
# If we have a resulting tree, that means the strategy module
# auto resolved the merge cleanly.
if test '' != "$result_tree"
then
if test "$allow_fast_forward" = "t"
then
parents=$(git show-branch --independent "$head" "$@")
else
parents=$(git rev-parse "$head" "$@")
fi
parents=$(echo "$parents" | sed -e 's/^/-p /')
result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
finish "$result_commit" "Merge made by $wt_strategy."
dropsave
exit 0
fi
# Pick the result from the best strategy and have the user fix it up.
case "$best_strategy" in
'')
restorestate
case "$use_strategies" in
?*' '?*)
echo >&2 "No merge strategy handled the merge."
;;
*)
echo >&2 "Merge with strategy $use_strategies failed."
;;
esac
exit 2
;;
"$wt_strategy")
# We already have its result in the working tree.
;;
*)
echo "Rewinding the tree to pristine..."
restorestate
echo "Using the $best_strategy to prepare resolving by hand."
git-merge-$best_strategy $common -- "$head_arg" "$@"
;;
esac
if test "$squash" = t
then
finish
else
for remote
do
echo $remote
done >"$GIT_DIR/MERGE_HEAD"
printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
fi
if test "$merge_was_ok" = t
then
echo >&2 \
"Automatic merge went well; stopped before committing as requested"
exit 0
else
{
echo '
Conflicts:
'
git ls-files --unmerged |
sed -e 's/^[^ ]* / /' |
uniq
} >>"$GIT_DIR/MERGE_MSG"
git rerere
die "Automatic merge failed; fix conflicts and then commit the result."
fi