config: Give error message when not changing a multivar
[git/dscho.git] / git-rebase--interactive.sh
blob41ba96aeb7f8ee32f7c346d5d7934f4d6b305d2f
1 #!/bin/sh
3 # Copyright (c) 2006 Johannes E. Schindelin
5 # SHORT DESCRIPTION
7 # This script makes it easy to fix up commits in the middle of a series,
8 # and rearrange commits.
10 # The original idea comes from Eric W. Biederman, in
11 # http://article.gmane.org/gmane.comp.version-control.git/22407
13 . git-sh-setup
15 # The file containing rebase commands, comments, and empty lines.
16 # This file is created by "git rebase -i" then edited by the user. As
17 # the lines are processed, they are removed from the front of this
18 # file and written to the tail of $done.
19 todo="$state_dir"/git-rebase-todo
21 # The rebase command lines that have already been processed. A line
22 # is moved here when it is first handled, before any associated user
23 # actions.
24 done="$state_dir"/done
26 # The commit message that is planned to be used for any changes that
27 # need to be committed following a user interaction.
28 msg="$state_dir"/message
30 # The file into which is accumulated the suggested commit message for
31 # squash/fixup commands. When the first of a series of squash/fixups
32 # is seen, the file is created and the commit message from the
33 # previous commit and from the first squash/fixup commit are written
34 # to it. The commit message for each subsequent squash/fixup commit
35 # is appended to the file as it is processed.
37 # The first line of the file is of the form
38 # # This is a combination of $count commits.
39 # where $count is the number of commits whose messages have been
40 # written to the file so far (including the initial "pick" commit).
41 # Each time that a commit message is processed, this line is read and
42 # updated. It is deleted just before the combined commit is made.
43 squash_msg="$state_dir"/message-squash
45 # If the current series of squash/fixups has not yet included a squash
46 # command, then this file exists and holds the commit message of the
47 # original "pick" commit. (If the series ends without a "squash"
48 # command, then this can be used as the commit message of the combined
49 # commit without opening the editor.)
50 fixup_msg="$state_dir"/message-fixup
52 # $rewritten is the name of a directory containing files for each
53 # commit that is reachable by at least one merge base of $head and
54 # $upstream. They are not necessarily rewritten, but their children
55 # might be. This ensures that commits on merged, but otherwise
56 # unrelated side branches are left alone. (Think "X" in the man page's
57 # example.)
58 rewritten="$state_dir"/rewritten
60 dropped="$state_dir"/dropped
62 # A script to set the GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
63 # GIT_AUTHOR_DATE that will be used for the commit that is currently
64 # being rebased.
65 author_script="$state_dir"/author-script
67 # When an "edit" rebase command is being processed, the SHA1 of the
68 # commit to be edited is recorded in this file. When "git rebase
69 # --continue" is executed, if there are any staged changes then they
70 # will be amended to the HEAD commit, but only provided the HEAD
71 # commit is still the commit to be edited. When any other rebase
72 # command is processed, this file is deleted.
73 amend="$state_dir"/amend
75 # For the post-rewrite hook, we make a list of rewritten commits and
76 # their new sha1s. The rewritten-pending list keeps the sha1s of
77 # commits that have been processed, but not committed yet,
78 # e.g. because they are waiting for a 'squash' command.
79 rewritten_list="$state_dir"/rewritten-list
80 rewritten_pending="$state_dir"/rewritten-pending
82 GIT_CHERRY_PICK_HELP="$resolvemsg"
83 export GIT_CHERRY_PICK_HELP
85 warn () {
86 printf '%s\n' "$*" >&2
89 # Output the commit message for the specified commit.
90 commit_message () {
91 git cat-file commit "$1" | sed "1,/^$/d"
94 orig_reflog_action="$GIT_REFLOG_ACTION"
96 comment_for_reflog () {
97 case "$orig_reflog_action" in
98 ''|rebase*)
99 GIT_REFLOG_ACTION="rebase -i ($1)"
100 export GIT_REFLOG_ACTION
102 esac
105 last_count=
106 mark_action_done () {
107 sed -e 1q < "$todo" >> "$done"
108 sed -e 1d < "$todo" >> "$todo".new
109 mv -f "$todo".new "$todo"
110 new_count=$(sane_grep -c '^[^#]' < "$done")
111 total=$(($new_count+$(sane_grep -c '^[^#]' < "$todo")))
112 if test "$last_count" != "$new_count"
113 then
114 last_count=$new_count
115 printf "Rebasing (%d/%d)\r" $new_count $total
116 test -z "$verbose" || echo
120 make_patch () {
121 sha1_and_parents="$(git rev-list --parents -1 "$1")"
122 case "$sha1_and_parents" in
123 ?*' '?*' '?*)
124 git diff --cc $sha1_and_parents
126 ?*' '?*)
127 git diff-tree -p "$1^!"
130 echo "Root commit"
132 esac > "$state_dir"/patch
133 test -f "$msg" ||
134 commit_message "$1" > "$msg"
135 test -f "$author_script" ||
136 get_author_ident_from_commit "$1" > "$author_script"
139 die_with_patch () {
140 echo "$1" > "$state_dir"/stopped-sha
141 make_patch "$1"
142 git rerere
143 die "$2"
146 die_abort () {
147 rm -rf "$state_dir"
148 die "$1"
151 has_action () {
152 sane_grep '^[^#]' "$1" >/dev/null
155 # Run command with GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
156 # GIT_AUTHOR_DATE exported from the current environment.
157 do_with_author () {
159 export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE
160 "$@"
164 pick_one () {
165 ff=--ff
166 case "$1" in -n) sha1=$2; ff= ;; *) sha1=$1 ;; esac
167 case "$force_rebase" in '') ;; ?*) ff= ;; esac
168 output git rev-parse --verify $sha1 || die "Invalid commit name: $sha1"
169 test -d "$rewritten" &&
170 pick_one_preserving_merges "$@" && return
171 output git cherry-pick $ff "$@"
174 pick_one_preserving_merges () {
175 fast_forward=t
176 case "$1" in
178 fast_forward=f
179 sha1=$2
182 sha1=$1
184 esac
185 sha1=$(git rev-parse $sha1)
187 if test -f "$state_dir"/current-commit
188 then
189 if test "$fast_forward" = t
190 then
191 while read current_commit
193 git rev-parse HEAD > "$rewritten"/$current_commit
194 done <"$state_dir"/current-commit
195 rm "$state_dir"/current-commit ||
196 die "Cannot write current commit's replacement sha1"
200 echo $sha1 >> "$state_dir"/current-commit
202 # rewrite parents; if none were rewritten, we can fast-forward.
203 new_parents=
204 pend=" $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)"
205 if test "$pend" = " "
206 then
207 pend=" root"
209 while [ "$pend" != "" ]
211 p=$(expr "$pend" : ' \([^ ]*\)')
212 pend="${pend# $p}"
214 if test -f "$rewritten"/$p
215 then
216 new_p=$(cat "$rewritten"/$p)
218 # If the todo reordered commits, and our parent is marked for
219 # rewriting, but hasn't been gotten to yet, assume the user meant to
220 # drop it on top of the current HEAD
221 if test -z "$new_p"
222 then
223 new_p=$(git rev-parse HEAD)
226 test $p != $new_p && fast_forward=f
227 case "$new_parents" in
228 *$new_p*)
229 ;; # do nothing; that parent is already there
231 new_parents="$new_parents $new_p"
233 esac
234 else
235 if test -f "$dropped"/$p
236 then
237 fast_forward=f
238 replacement="$(cat "$dropped"/$p)"
239 test -z "$replacement" && replacement=root
240 pend=" $replacement$pend"
241 else
242 new_parents="$new_parents $p"
245 done
246 case $fast_forward in
248 output warn "Fast-forward to $sha1"
249 output git reset --hard $sha1 ||
250 die "Cannot fast-forward to $sha1"
253 first_parent=$(expr "$new_parents" : ' \([^ ]*\)')
255 if [ "$1" != "-n" ]
256 then
257 # detach HEAD to current parent
258 output git checkout $first_parent 2> /dev/null ||
259 die "Cannot move HEAD to $first_parent"
262 case "$new_parents" in
263 ' '*' '*)
264 test "a$1" = a-n && die "Refusing to squash a merge: $sha1"
266 # redo merge
267 author_script_content=$(get_author_ident_from_commit $sha1)
268 eval "$author_script_content"
269 msg_content="$(commit_message $sha1)"
270 # No point in merging the first parent, that's HEAD
271 new_parents=${new_parents# $first_parent}
272 if ! do_with_author output \
273 git merge --no-ff ${strategy:+-s $strategy} -m \
274 "$msg_content" $new_parents
275 then
276 printf "%s\n" "$msg_content" > "$GIT_DIR"/MERGE_MSG
277 die_with_patch $sha1 "Error redoing merge $sha1"
279 echo "$sha1 $(git rev-parse HEAD^0)" >> "$rewritten_list"
282 output git cherry-pick "$@" ||
283 die_with_patch $sha1 "Could not pick $sha1"
285 esac
287 esac
290 nth_string () {
291 case "$1" in
292 *1[0-9]|*[04-9]) echo "$1"th;;
293 *1) echo "$1"st;;
294 *2) echo "$1"nd;;
295 *3) echo "$1"rd;;
296 esac
299 update_squash_messages () {
300 if test -f "$squash_msg"; then
301 mv "$squash_msg" "$squash_msg".bak || exit
302 count=$(($(sed -n \
303 -e "1s/^# This is a combination of \(.*\) commits\./\1/p" \
304 -e "q" < "$squash_msg".bak)+1))
306 echo "# This is a combination of $count commits."
307 sed -e 1d -e '2,/^./{
308 /^$/d
309 }' <"$squash_msg".bak
310 } >"$squash_msg"
311 else
312 commit_message HEAD > "$fixup_msg" || die "Cannot write $fixup_msg"
313 count=2
315 echo "# This is a combination of 2 commits."
316 echo "# The first commit's message is:"
317 echo
318 cat "$fixup_msg"
319 } >"$squash_msg"
321 case $1 in
322 squash)
323 rm -f "$fixup_msg"
324 echo
325 echo "# This is the $(nth_string $count) commit message:"
326 echo
327 commit_message $2
329 fixup)
330 echo
331 echo "# The $(nth_string $count) commit message will be skipped:"
332 echo
333 commit_message $2 | sed -e 's/^/# /'
335 esac >>"$squash_msg"
338 peek_next_command () {
339 sed -n -e "/^#/d" -e '/^$/d' -e "s/ .*//p" -e "q" < "$todo"
342 # A squash/fixup has failed. Prepare the long version of the squash
343 # commit message, then die_with_patch. This code path requires the
344 # user to edit the combined commit message for all commits that have
345 # been squashed/fixedup so far. So also erase the old squash
346 # messages, effectively causing the combined commit to be used as the
347 # new basis for any further squash/fixups. Args: sha1 rest
348 die_failed_squash() {
349 mv "$squash_msg" "$msg" || exit
350 rm -f "$fixup_msg"
351 cp "$msg" "$GIT_DIR"/MERGE_MSG || exit
352 warn
353 warn "Could not apply $1... $2"
354 die_with_patch $1 ""
357 flush_rewritten_pending() {
358 test -s "$rewritten_pending" || return
359 newsha1="$(git rev-parse HEAD^0)"
360 sed "s/$/ $newsha1/" < "$rewritten_pending" >> "$rewritten_list"
361 rm -f "$rewritten_pending"
364 record_in_rewritten() {
365 oldsha1="$(git rev-parse $1)"
366 echo "$oldsha1" >> "$rewritten_pending"
368 case "$(peek_next_command)" in
369 squash|s|fixup|f)
372 flush_rewritten_pending
374 esac
377 do_next () {
378 rm -f "$msg" "$author_script" "$amend" || exit
379 read -r command sha1 rest < "$todo"
380 case "$command" in
381 '#'*|''|noop)
382 mark_action_done
384 pick|p)
385 comment_for_reflog pick
387 mark_action_done
388 pick_one $sha1 ||
389 die_with_patch $sha1 "Could not apply $sha1... $rest"
390 record_in_rewritten $sha1
392 reword|r)
393 comment_for_reflog reword
395 mark_action_done
396 pick_one $sha1 ||
397 die_with_patch $sha1 "Could not apply $sha1... $rest"
398 git commit --amend --no-post-rewrite
399 record_in_rewritten $sha1
401 edit|e)
402 comment_for_reflog edit
404 mark_action_done
405 pick_one $sha1 ||
406 die_with_patch $sha1 "Could not apply $sha1... $rest"
407 echo "$sha1" > "$state_dir"/stopped-sha
408 make_patch $sha1
409 git rev-parse --verify HEAD > "$amend"
410 warn "Stopped at $sha1... $rest"
411 warn "You can amend the commit now, with"
412 warn
413 warn " git commit --amend"
414 warn
415 warn "Once you are satisfied with your changes, run"
416 warn
417 warn " git rebase --continue"
418 warn
419 exit 0
421 squash|s|fixup|f)
422 case "$command" in
423 squash|s)
424 squash_style=squash
426 fixup|f)
427 squash_style=fixup
429 esac
430 comment_for_reflog $squash_style
432 test -f "$done" && has_action "$done" ||
433 die "Cannot '$squash_style' without a previous commit"
435 mark_action_done
436 update_squash_messages $squash_style $sha1
437 author_script_content=$(get_author_ident_from_commit HEAD)
438 echo "$author_script_content" > "$author_script"
439 eval "$author_script_content"
440 output git reset --soft HEAD^
441 pick_one -n $sha1 || die_failed_squash $sha1 "$rest"
442 case "$(peek_next_command)" in
443 squash|s|fixup|f)
444 # This is an intermediate commit; its message will only be
445 # used in case of trouble. So use the long version:
446 do_with_author output git commit --no-verify -F "$squash_msg" ||
447 die_failed_squash $sha1 "$rest"
450 # This is the final command of this squash/fixup group
451 if test -f "$fixup_msg"
452 then
453 do_with_author git commit --no-verify -F "$fixup_msg" ||
454 die_failed_squash $sha1 "$rest"
455 else
456 cp "$squash_msg" "$GIT_DIR"/SQUASH_MSG || exit
457 rm -f "$GIT_DIR"/MERGE_MSG
458 do_with_author git commit --no-verify -e ||
459 die_failed_squash $sha1 "$rest"
461 rm -f "$squash_msg" "$fixup_msg"
463 esac
464 record_in_rewritten $sha1
466 x|"exec")
467 read -r command rest < "$todo"
468 mark_action_done
469 printf 'Executing: %s\n' "$rest"
470 # "exec" command doesn't take a sha1 in the todo-list.
471 # => can't just use $sha1 here.
472 git rev-parse --verify HEAD > "$state_dir"/stopped-sha
473 ${SHELL:-@SHELL_PATH@} -c "$rest" # Actual execution
474 status=$?
475 if test "$status" -ne 0
476 then
477 warn "Execution failed: $rest"
478 warn "You can fix the problem, and then run"
479 warn
480 warn " git rebase --continue"
481 warn
482 exit "$status"
484 # Run in subshell because require_clean_work_tree can die.
485 if ! (require_clean_work_tree "rebase")
486 then
487 warn "Commit or stash your changes, and then run"
488 warn
489 warn " git rebase --continue"
490 warn
491 exit 1
495 warn "Unknown command: $command $sha1 $rest"
496 if git rev-parse --verify -q "$sha1" >/dev/null
497 then
498 die_with_patch $sha1 "Please fix this in the file $todo."
499 else
500 die "Please fix this in the file $todo."
503 esac
504 test -s "$todo" && return
506 comment_for_reflog finish &&
507 shortonto=$(git rev-parse --short $onto) &&
508 newhead=$(git rev-parse HEAD) &&
509 case $head_name in
510 refs/*)
511 message="$GIT_REFLOG_ACTION: $head_name onto $shortonto" &&
512 git update-ref -m "$message" $head_name $newhead $orig_head &&
513 git symbolic-ref HEAD $head_name
515 esac && {
516 test ! -f "$state_dir"/verbose ||
517 git diff-tree --stat $orig_head..HEAD
518 } &&
520 test -s "$rewritten_list" &&
521 git notes copy --for-rewrite=rebase < "$rewritten_list" ||
522 true # we don't care if this copying failed
523 } &&
524 if test -x "$GIT_DIR"/hooks/post-rewrite &&
525 test -s "$rewritten_list"; then
526 "$GIT_DIR"/hooks/post-rewrite rebase < "$rewritten_list"
527 true # we don't care if this hook failed
528 fi &&
529 rm -rf "$state_dir" &&
530 git gc --auto &&
531 warn "Successfully rebased and updated $head_name."
533 exit
536 do_rest () {
537 while :
539 do_next
540 done
543 # skip picking commits whose parents are unchanged
544 skip_unnecessary_picks () {
545 fd=3
546 while read -r command rest
548 # fd=3 means we skip the command
549 case "$fd,$command" in
550 3,pick|3,p)
551 # pick a commit whose parent is current $onto -> skip
552 sha1=${rest%% *}
553 case "$(git rev-parse --verify --quiet "$sha1"^)" in
554 "$onto"*)
555 onto=$sha1
558 fd=1
560 esac
562 3,#*|3,)
563 # copy comments
566 fd=1
568 esac
569 printf '%s\n' "$command${rest:+ }$rest" >&$fd
570 done <"$todo" >"$todo.new" 3>>"$done" &&
571 mv -f "$todo".new "$todo" &&
572 case "$(peek_next_command)" in
573 squash|s|fixup|f)
574 record_in_rewritten "$onto"
576 esac ||
577 die "Could not skip unnecessary pick commands"
580 # Rearrange the todo list that has both "pick sha1 msg" and
581 # "pick sha1 fixup!/squash! msg" appears in it so that the latter
582 # comes immediately after the former, and change "pick" to
583 # "fixup"/"squash".
584 rearrange_squash () {
585 # extract fixup!/squash! lines and resolve any referenced sha1's
586 while read -r pick sha1 message
588 case "$message" in
589 "squash! "*|"fixup! "*)
590 action="${message%%!*}"
591 rest="${message#*! }"
592 echo "$sha1 $action $rest"
593 # if it's a single word, try to resolve to a full sha1 and
594 # emit a second copy. This allows us to match on both message
595 # and on sha1 prefix
596 if test "${rest#* }" = "$rest"; then
597 fullsha="$(git rev-parse -q --verify "$rest" 2>/dev/null)"
598 if test -n "$fullsha"; then
599 # prefix the action to uniquely identify this line as
600 # intended for full sha1 match
601 echo "$sha1 +$action $fullsha"
604 esac
605 done >"$1.sq" <"$1"
606 test -s "$1.sq" || return
608 used=
609 while read -r pick sha1 message
611 case " $used" in
612 *" $sha1 "*) continue ;;
613 esac
614 printf '%s\n' "$pick $sha1 $message"
615 used="$used$sha1 "
616 while read -r squash action msg_content
618 case " $used" in
619 *" $squash "*) continue ;;
620 esac
621 emit=0
622 case "$action" in
624 action="${action#+}"
625 # full sha1 prefix test
626 case "$msg_content" in "$sha1"*) emit=1;; esac ;;
628 # message prefix test
629 case "$message" in "$msg_content"*) emit=1;; esac ;;
630 esac
631 if test $emit = 1; then
632 printf '%s\n' "$action $squash $action! $msg_content"
633 used="$used$squash "
635 done <"$1.sq"
636 done >"$1.rearranged" <"$1"
637 cat "$1.rearranged" >"$1"
638 rm -f "$1.sq" "$1.rearranged"
641 case "$action" in
642 continue)
643 # do we have anything to commit?
644 if git diff-index --cached --quiet --ignore-submodules HEAD --
645 then
646 : Nothing to commit -- skip this
647 else
648 . "$author_script" ||
649 die "Cannot find the author identity"
650 current_head=
651 if test -f "$amend"
652 then
653 current_head=$(git rev-parse --verify HEAD)
654 test "$current_head" = $(cat "$amend") ||
655 die "\
656 You have uncommitted changes in your working tree. Please, commit them
657 first and then run 'git rebase --continue' again."
658 git reset --soft HEAD^ ||
659 die "Cannot rewind the HEAD"
661 do_with_author git commit --no-verify -F "$msg" -e || {
662 test -n "$current_head" && git reset --soft $current_head
663 die "Could not commit staged changes."
667 record_in_rewritten "$(cat "$state_dir"/stopped-sha)"
669 require_clean_work_tree "rebase"
670 do_rest
672 skip)
673 git rerere clear
675 do_rest
677 esac
679 git var GIT_COMMITTER_IDENT >/dev/null ||
680 die "You need to set your committer info first"
682 comment_for_reflog start
684 if test ! -z "$switch_to"
685 then
686 output git checkout "$switch_to" -- ||
687 die "Could not checkout $switch_to"
690 orig_head=$(git rev-parse --verify HEAD) || die "No HEAD?"
691 mkdir "$state_dir" || die "Could not create temporary $state_dir"
693 : > "$state_dir"/interactive || die "Could not mark as interactive"
694 write_basic_state
695 if test t = "$preserve_merges"
696 then
697 if test -z "$rebase_root"
698 then
699 mkdir "$rewritten" &&
700 for c in $(git merge-base --all $orig_head $upstream)
702 echo $onto > "$rewritten"/$c ||
703 die "Could not init rewritten commits"
704 done
705 else
706 mkdir "$rewritten" &&
707 echo $onto > "$rewritten"/root ||
708 die "Could not init rewritten commits"
710 # No cherry-pick because our first pass is to determine
711 # parents to rewrite and skipping dropped commits would
712 # prematurely end our probe
713 merges_option=
714 first_after_upstream="$(git rev-list --reverse --first-parent $upstream..$orig_head | head -n 1)"
715 else
716 merges_option="--no-merges --cherry-pick"
719 shorthead=$(git rev-parse --short $orig_head)
720 shortonto=$(git rev-parse --short $onto)
721 if test -z "$rebase_root"
722 # this is now equivalent to ! -z "$upstream"
723 then
724 shortupstream=$(git rev-parse --short $upstream)
725 revisions=$upstream...$orig_head
726 shortrevisions=$shortupstream..$shorthead
727 else
728 revisions=$onto...$orig_head
729 shortrevisions=$shorthead
731 git rev-list $merges_option --pretty=oneline --abbrev-commit \
732 --abbrev=7 --reverse --left-right --topo-order \
733 $revisions | \
734 sed -n "s/^>//p" |
735 while read -r shortsha1 rest
737 if test t != "$preserve_merges"
738 then
739 printf '%s\n' "pick $shortsha1 $rest" >> "$todo"
740 else
741 sha1=$(git rev-parse $shortsha1)
742 if test -z "$rebase_root"
743 then
744 preserve=t
745 for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)
747 if test -f "$rewritten"/$p -a \( $p != $onto -o $sha1 = $first_after_upstream \)
748 then
749 preserve=f
751 done
752 else
753 preserve=f
755 if test f = "$preserve"
756 then
757 touch "$rewritten"/$sha1
758 printf '%s\n' "pick $shortsha1 $rest" >> "$todo"
761 done
763 # Watch for commits that been dropped by --cherry-pick
764 if test t = "$preserve_merges"
765 then
766 mkdir "$dropped"
767 # Save all non-cherry-picked changes
768 git rev-list $revisions --left-right --cherry-pick | \
769 sed -n "s/^>//p" > "$state_dir"/not-cherry-picks
770 # Now all commits and note which ones are missing in
771 # not-cherry-picks and hence being dropped
772 git rev-list $revisions |
773 while read rev
775 if test -f "$rewritten"/$rev -a "$(sane_grep "$rev" "$state_dir"/not-cherry-picks)" = ""
776 then
777 # Use -f2 because if rev-list is telling us this commit is
778 # not worthwhile, we don't want to track its multiple heads,
779 # just the history of its first-parent for others that will
780 # be rebasing on top of it
781 git rev-list --parents -1 $rev | cut -d' ' -s -f2 > "$dropped"/$rev
782 short=$(git rev-list -1 --abbrev-commit --abbrev=7 $rev)
783 sane_grep -v "^[a-z][a-z]* $short" <"$todo" > "${todo}2" ; mv "${todo}2" "$todo"
784 rm "$rewritten"/$rev
786 done
789 test -s "$todo" || echo noop >> "$todo"
790 test -n "$autosquash" && rearrange_squash "$todo"
791 cat >> "$todo" << EOF
793 # Rebase $shortrevisions onto $shortonto
795 # Commands:
796 # p, pick = use commit
797 # r, reword = use commit, but edit the commit message
798 # e, edit = use commit, but stop for amending
799 # s, squash = use commit, but meld into previous commit
800 # f, fixup = like "squash", but discard this commit's log message
801 # x, exec = run command (the rest of the line) using shell
803 # If you remove a line here THAT COMMIT WILL BE LOST.
804 # However, if you remove everything, the rebase will be aborted.
808 has_action "$todo" ||
809 die_abort "Nothing to do"
811 cp "$todo" "$todo".backup
812 git_editor "$todo" ||
813 die_abort "Could not execute editor"
815 has_action "$todo" ||
816 die_abort "Nothing to do"
818 test -d "$rewritten" || test -n "$force_rebase" || skip_unnecessary_picks
820 output git checkout $onto || die_abort "could not detach HEAD"
821 git update-ref ORIG_HEAD $orig_head
822 do_rest