git-commit-vandalism/git-merge.sh
Junio C Hamano e3b59a44f6 Keep Porcelainish from failing by broken ident after making changes.
"empty ident not allowed" error makes commit-tree fail, so we
are already safer in that we would not end up with commit
objects that have bogus names on the author or committer fields.
However, before commit-tree is called there are already changes
made to the index file and the working tree.  The operation can
be resumed after fixing the environment problem, but when this
triggers to a newcomer with unusable gecos, the first question
becomes "what did I lose and how would I recover".

This patch modifies some Porcelainish commands to verify
GIT_COMMITTER_IDENT as soon as we know we are going to make some
commits before doing much damage to prevent confusion.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-02-18 20:51:26 -08:00

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#!/bin/sh
#
# Copyright (c) 2005 Junio C Hamano
#
USAGE='[-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+'
. git-sh-setup
LF='
'
all_strategies='recursive octopus resolve stupid ours'
default_strategies='recursive'
use_strategies=
dropsave() {
rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
"$GIT_DIR/MERGE_SAVE" || exit 1
}
savestate() {
# Stash away any local modifications.
git-diff-index -z --name-only $head |
cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
}
restorestate() {
if test -f "$GIT_DIR/MERGE_SAVE"
then
git reset --hard $head
cpio -iuv <"$GIT_DIR/MERGE_SAVE"
git-update-index --refresh >/dev/null
fi
}
finish () {
test '' = "$2" || echo "$2"
case "$merge_msg" in
'')
echo "No merge message -- not updating HEAD"
;;
*)
git-update-ref HEAD "$1" "$head" || exit 1
;;
esac
case "$no_summary" in
'')
git-diff-tree -p -M "$head" "$1" |
git-apply --stat --summary
;;
esac
}
while case "$#" in 0) break ;; esac
do
case "$1" in
-n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
--no-summa|--no-summar|--no-summary)
no_summary=t ;;
--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
no_commit=t ;;
-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
--strateg=*|--strategy=*|\
-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
case "$#,$1" in
*,*=*)
strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
1,*)
usage ;;
*)
strategy="$2"
shift ;;
esac
case " $all_strategies " in
*" $strategy "*)
use_strategies="$use_strategies$strategy " ;;
*)
die "available strategies are: $all_strategies" ;;
esac
;;
-*) usage ;;
*) break ;;
esac
shift
done
test "$#" -le 2 && usage ;# we need at least two heads.
merge_msg="$1"
shift
head_arg="$1"
head=$(git-rev-parse --verify "$1"^0) || usage
shift
# All the rest are remote heads
remoteheads=
for remote
do
remotehead=$(git-rev-parse --verify "$remote"^0) ||
die "$remote - not something we can merge"
remoteheads="${remoteheads}$remotehead "
done
set x $remoteheads ; shift
case "$#" in
1)
common=$(git-merge-base --all $head "$@")
;;
*)
common=$(git-show-branch --merge-base $head "$@")
;;
esac
echo "$head" >"$GIT_DIR/ORIG_HEAD"
case "$#,$common,$no_commit" in
*,'',*)
# No common ancestors found. We need a real merge.
;;
1,"$1",*)
# If head can reach all the merge then we are up to date.
# but first the most common case of merging one remote
echo "Already up-to-date."
dropsave
exit 0
;;
1,"$head",*)
# Again the most common case of merging one remote.
echo "Updating from $head to $1."
git-update-index --refresh 2>/dev/null
new_head=$(git-rev-parse --verify "$1^0") &&
git-read-tree -u -m $head "$new_head" &&
finish "$new_head" "Fast forward"
dropsave
exit 0
;;
1,?*"$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. See if it is really trivial.
git var GIT_COMMITTER_IDENT >/dev/null || exit
echo "Trying really trivial in-index merge..."
git-update-index --refresh 2>/dev/null
if git-read-tree --trivial -m -u $common $head "$1" &&
result_tree=$(git-write-tree)
then
echo "Wonderful."
result_commit=$(
echo "$merge_msg" |
git-commit-tree $result_tree -p HEAD -p "$1"
) || exit
finish "$result_commit" "In-index merge"
dropsave
exit 0
fi
echo "Nope."
;;
*)
# 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
echo "Already up-to-date. Yeeah!"
dropsave
exit 0
fi
;;
esac
# We are going to make a new commit.
git var GIT_COMMITTER_IDENT >/dev/null || exit
case "$use_strategies" in
'')
case "$#" in
1)
use_strategies="$default_strategies" ;;
*)
use_strategies=octopus ;;
esac
;;
esac
# 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_SAVE"
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
parents="-p $head"
for remote
do
parents="$parents -p $remote"
done
result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
finish "$result_commit" "Merge $result_commit, 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
echo >&2 "No merge strategy handled the merge."
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
for remote
do
echo $remote
done >"$GIT_DIR/MERGE_HEAD"
echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
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"
if test -d "$GIT_DIR/rr-cache"
then
git-rerere
fi
die "Automatic merge failed; fix up by hand"
fi