git/git-rebase--merge.sh
Ben Woosley 79f43447d2 git-rebase--merge: don't include absent parent as a base
Absent this fix, attempts to rebase an orphan branch using "rebase -m"
fails with:

    $ git rebase -m ORPHAN_TARGET_BASE
    First, rewinding head to replay your work on top of it...
    fatal: Could not parse object 'ORPHAN_ROOT_SHA^'
    Unknown exit code (128) from command: git-merge-recursive ORPHAN_ROOT_SHA^ -- HEAD ORPHAN_ROOT_SHA

To fix, this will only include the rebase root's parent as a base if it exists,
so that in cases of rebasing an orphan branch, it is a simple two-way merge.

Note the default rebase behavior does not fail:

    $ git rebase ORPHAN_TARGET_BASE
    First, rewinding head to replay your work on top of it...
    Applying: ORPHAN_ROOT_COMMIT_MSG
    Using index info to reconstruct a base tree...

A few tests were expecting the old behaviour to forbid rebasing such
a history with "rebase -m", which now need to expect them to succeed.

Signed-off-by: Ben Woosley <ben.woosley@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-24 12:05:08 -07:00

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# This shell script fragment is sourced by git-rebase to implement
# its merge-based non-interactive mode that copes well with renamed
# files.
#
# Copyright (c) 2010 Junio C Hamano.
#
prec=4
read_state () {
onto_name=$(cat "$state_dir"/onto_name) &&
end=$(cat "$state_dir"/end) &&
msgnum=$(cat "$state_dir"/msgnum)
}
continue_merge () {
test -d "$state_dir" || die "$state_dir directory does not exist"
unmerged=$(git ls-files -u)
if test -n "$unmerged"
then
echo "You still have unmerged paths in your index"
echo "did you forget to use git add?"
die "$resolvemsg"
fi
cmt=$(cat "$state_dir/current")
if ! git diff-index --quiet --ignore-submodules HEAD --
then
if ! git commit ${gpg_sign_opt:+"$gpg_sign_opt"} --no-verify -C "$cmt"
then
echo "Commit failed, please do not call \"git commit\""
echo "directly, but instead do one of the following: "
die "$resolvemsg"
fi
if test -z "$GIT_QUIET"
then
printf "Committed: %0${prec}d " $msgnum
fi
echo "$cmt $(git rev-parse HEAD^0)" >> "$state_dir/rewritten"
else
if test -z "$GIT_QUIET"
then
printf "Already applied: %0${prec}d " $msgnum
fi
fi
test -z "$GIT_QUIET" &&
GIT_PAGER='' git log --format=%s -1 "$cmt"
# onto the next patch:
msgnum=$(($msgnum + 1))
echo "$msgnum" >"$state_dir/msgnum"
}
call_merge () {
msgnum="$1"
echo "$msgnum" >"$state_dir/msgnum"
cmt="$(cat "$state_dir/cmt.$msgnum")"
echo "$cmt" > "$state_dir/current"
hd=$(git rev-parse --verify HEAD)
cmt_name=$(git symbolic-ref HEAD 2> /dev/null || echo HEAD)
eval GITHEAD_$cmt='"${cmt_name##refs/heads/}~$(($end - $msgnum))"'
eval GITHEAD_$hd='$onto_name'
export GITHEAD_$cmt GITHEAD_$hd
if test -n "$GIT_QUIET"
then
GIT_MERGE_VERBOSITY=1 && export GIT_MERGE_VERBOSITY
fi
test -z "$strategy" && strategy=recursive
# If cmt doesn't have a parent, don't include it as a base
base=$(git rev-parse --verify --quiet $cmt^)
eval 'git-merge-$strategy' $strategy_opts $base ' -- "$hd" "$cmt"'
rv=$?
case "$rv" in
0)
unset GITHEAD_$cmt GITHEAD_$hd
return
;;
1)
git rerere $allow_rerere_autoupdate
die "$resolvemsg"
;;
2)
echo "Strategy: $strategy failed, try another" 1>&2
die "$resolvemsg"
;;
*)
die "Unknown exit code ($rv) from command:" \
"git-merge-$strategy $cmt^ -- HEAD $cmt"
;;
esac
}
finish_rb_merge () {
move_to_original_branch
if test -s "$state_dir"/rewritten
then
git notes copy --for-rewrite=rebase <"$state_dir"/rewritten
hook="$(git rev-parse --git-path hooks/post-rewrite)"
test -x "$hook" && "$hook" rebase <"$state_dir"/rewritten
fi
say All done.
}
# The whole contents of this file is run by dot-sourcing it from
# inside a shell function. It used to be that "return"s we see
# below were not inside any function, and expected to return
# to the function that dot-sourced us.
#
# However, FreeBSD /bin/sh misbehaves on such a construct and
# continues to run the statements that follow such a "return".
# As a work-around, we introduce an extra layer of a function
# here, and immediately call it after defining it.
git_rebase__merge () {
case "$action" in
continue)
read_state
continue_merge
while test "$msgnum" -le "$end"
do
call_merge "$msgnum"
continue_merge
done
finish_rb_merge
return
;;
skip)
read_state
git rerere clear
msgnum=$(($msgnum + 1))
while test "$msgnum" -le "$end"
do
call_merge "$msgnum"
continue_merge
done
finish_rb_merge
return
;;
esac
mkdir -p "$state_dir"
echo "$onto_name" > "$state_dir/onto_name"
write_basic_state
msgnum=0
for cmt in $(git rev-list --reverse --no-merges "$revisions")
do
msgnum=$(($msgnum + 1))
echo "$cmt" > "$state_dir/cmt.$msgnum"
done
echo 1 >"$state_dir/msgnum"
echo $msgnum >"$state_dir/end"
end=$msgnum
msgnum=1
while test "$msgnum" -le "$end"
do
call_merge "$msgnum"
continue_merge
done
finish_rb_merge
}
# ... and then we call the whole thing.
git_rebase__merge