provide more errors for the "merge into empty head" case
[git] / git-rebase.sh
1 #!/bin/sh
2 #
3 # Copyright (c) 2005 Junio C Hamano.
4 #
5
6 USAGE='[--interactive | -i] [-v] [--onto <newbase>] <upstream> [<branch>]'
7 LONG_USAGE='git-rebase replaces <branch> with a new branch of the
8 same name.  When the --onto option is provided the new branch starts
9 out with a HEAD equal to <newbase>, otherwise it is equal to <upstream>
10 It then attempts to create a new commit for each commit from the original
11 <branch> that does not exist in the <upstream> branch.
12
13 It is possible that a merge failure will prevent this process from being
14 completely automatic.  You will have to resolve any such merge failure
15 and run git rebase --continue.  Another option is to bypass the commit
16 that caused the merge failure with git rebase --skip.  To restore the
17 original <branch> and remove the .git/rebase-apply working files, use the
18 command git rebase --abort instead.
19
20 Note that if <branch> is not specified on the command line, the
21 currently checked out branch is used.
22
23 Example:       git-rebase master~1 topic
24
25         A---B---C topic                   A'\''--B'\''--C'\'' topic
26        /                   -->           /
27   D---E---F---G master          D---E---F---G master
28 '
29
30 SUBDIRECTORY_OK=Yes
31 OPTIONS_SPEC=
32 . git-sh-setup
33 set_reflog_action rebase
34 require_work_tree
35 cd_to_toplevel
36
37 RESOLVEMSG="
38 When you have resolved this problem run \"git rebase --continue\".
39 If you would prefer to skip this patch, instead run \"git rebase --skip\".
40 To restore the original branch and stop rebasing run \"git rebase --abort\".
41 "
42 unset newbase
43 strategy=recursive
44 do_merge=
45 dotest="$GIT_DIR"/rebase-merge
46 prec=4
47 verbose=
48 git_am_opt=
49
50 continue_merge () {
51         test -n "$prev_head" || die "prev_head must be defined"
52         test -d "$dotest" || die "$dotest directory does not exist"
53
54         unmerged=$(git ls-files -u)
55         if test -n "$unmerged"
56         then
57                 echo "You still have unmerged paths in your index"
58                 echo "did you forget to use git add?"
59                 die "$RESOLVEMSG"
60         fi
61
62         cmt=`cat "$dotest/current"`
63         if ! git diff-index --quiet --ignore-submodules HEAD --
64         then
65                 if ! git commit --no-verify -C "$cmt"
66                 then
67                         echo "Commit failed, please do not call \"git commit\""
68                         echo "directly, but instead do one of the following: "
69                         die "$RESOLVEMSG"
70                 fi
71                 printf "Committed: %0${prec}d " $msgnum
72         else
73                 printf "Already applied: %0${prec}d " $msgnum
74         fi
75         git rev-list --pretty=oneline -1 "$cmt" | sed -e 's/^[^ ]* //'
76
77         prev_head=`git rev-parse HEAD^0`
78         # save the resulting commit so we can read-tree on it later
79         echo "$prev_head" > "$dotest/prev_head"
80
81         # onto the next patch:
82         msgnum=$(($msgnum + 1))
83         echo "$msgnum" >"$dotest/msgnum"
84 }
85
86 call_merge () {
87         cmt="$(cat "$dotest/cmt.$1")"
88         echo "$cmt" > "$dotest/current"
89         hd=$(git rev-parse --verify HEAD)
90         cmt_name=$(git symbolic-ref HEAD 2> /dev/null || echo HEAD)
91         msgnum=$(cat "$dotest/msgnum")
92         end=$(cat "$dotest/end")
93         eval GITHEAD_$cmt='"${cmt_name##refs/heads/}~$(($end - $msgnum))"'
94         eval GITHEAD_$hd='$(cat "$dotest/onto_name")'
95         export GITHEAD_$cmt GITHEAD_$hd
96         git-merge-$strategy "$cmt^" -- "$hd" "$cmt"
97         rv=$?
98         case "$rv" in
99         0)
100                 unset GITHEAD_$cmt GITHEAD_$hd
101                 return
102                 ;;
103         1)
104                 git rerere
105                 die "$RESOLVEMSG"
106                 ;;
107         2)
108                 echo "Strategy: $rv $strategy failed, try another" 1>&2
109                 die "$RESOLVEMSG"
110                 ;;
111         *)
112                 die "Unknown exit code ($rv) from command:" \
113                         "git-merge-$strategy $cmt^ -- HEAD $cmt"
114                 ;;
115         esac
116 }
117
118 move_to_original_branch () {
119         test -z "$head_name" &&
120                 head_name="$(cat "$dotest"/head-name)" &&
121                 onto="$(cat "$dotest"/onto)" &&
122                 orig_head="$(cat "$dotest"/orig-head)"
123         case "$head_name" in
124         refs/*)
125                 message="rebase finished: $head_name onto $onto"
126                 git update-ref -m "$message" \
127                         $head_name $(git rev-parse HEAD) $orig_head &&
128                 git symbolic-ref HEAD $head_name ||
129                 die "Could not move back to $head_name"
130                 ;;
131         esac
132 }
133
134 finish_rb_merge () {
135         move_to_original_branch
136         rm -r "$dotest"
137         echo "All done."
138 }
139
140 is_interactive () {
141         test -f "$dotest"/interactive ||
142         while :; do case $#,"$1" in 0,|*,-i|*,--interactive) break ;; esac
143                 shift
144         done && test -n "$1"
145 }
146
147 test -f "$GIT_DIR"/rebase-apply/applying &&
148         die 'It looks like git-am is in progress. Cannot rebase.'
149
150 is_interactive "$@" && exec git-rebase--interactive "$@"
151
152 if test $# -eq 0
153 then
154         test -d "$dotest" -o -d "$GIT_DIR"/rebase-apply || usage
155         test -d "$dotest" -o -f "$GIT_DIR"/rebase-apply/rebasing &&
156                 die 'A rebase is in progress, try --continue, --skip or --abort.'
157         die "No arguments given and $GIT_DIR/rebase-apply already exists."
158 fi
159
160 while test $# != 0
161 do
162         case "$1" in
163         --continue)
164                 test -d "$dotest" -o -d "$GIT_DIR"/rebase-apply ||
165                         die "No rebase in progress?"
166
167                 git diff-files --quiet --ignore-submodules || {
168                         echo "You must edit all merge conflicts and then"
169                         echo "mark them as resolved using git add"
170                         exit 1
171                 }
172                 if test -d "$dotest"
173                 then
174                         prev_head=$(cat "$dotest/prev_head")
175                         end=$(cat "$dotest/end")
176                         msgnum=$(cat "$dotest/msgnum")
177                         onto=$(cat "$dotest/onto")
178                         continue_merge
179                         while test "$msgnum" -le "$end"
180                         do
181                                 call_merge "$msgnum"
182                                 continue_merge
183                         done
184                         finish_rb_merge
185                         exit
186                 fi
187                 head_name=$(cat "$GIT_DIR"/rebase-apply/head-name) &&
188                 onto=$(cat "$GIT_DIR"/rebase-apply/onto) &&
189                 orig_head=$(cat "$GIT_DIR"/rebase-apply/orig-head) &&
190                 git am --resolved --3way --resolvemsg="$RESOLVEMSG" &&
191                 move_to_original_branch
192                 exit
193                 ;;
194         --skip)
195                 test -d "$dotest" -o -d "$GIT_DIR"/rebase-apply ||
196                         die "No rebase in progress?"
197
198                 git reset --hard HEAD || exit $?
199                 if test -d "$dotest"
200                 then
201                         git rerere clear
202                         prev_head=$(cat "$dotest/prev_head")
203                         end=$(cat "$dotest/end")
204                         msgnum=$(cat "$dotest/msgnum")
205                         msgnum=$(($msgnum + 1))
206                         onto=$(cat "$dotest/onto")
207                         while test "$msgnum" -le "$end"
208                         do
209                                 call_merge "$msgnum"
210                                 continue_merge
211                         done
212                         finish_rb_merge
213                         exit
214                 fi
215                 head_name=$(cat "$GIT_DIR"/rebase-apply/head-name) &&
216                 onto=$(cat "$GIT_DIR"/rebase-apply/onto) &&
217                 orig_head=$(cat "$GIT_DIR"/rebase-apply/orig-head) &&
218                 git am -3 --skip --resolvemsg="$RESOLVEMSG" &&
219                 move_to_original_branch
220                 exit
221                 ;;
222         --abort)
223                 test -d "$dotest" -o -d "$GIT_DIR"/rebase-apply ||
224                         die "No rebase in progress?"
225
226                 git rerere clear
227                 if test -d "$dotest"
228                 then
229                         move_to_original_branch
230                 else
231                         dotest="$GIT_DIR"/rebase-apply
232                         move_to_original_branch
233                 fi
234                 git reset --hard $(cat "$dotest/orig-head")
235                 rm -r "$dotest"
236                 exit
237                 ;;
238         --onto)
239                 test 2 -le "$#" || usage
240                 newbase="$2"
241                 shift
242                 ;;
243         -M|-m|--m|--me|--mer|--merg|--merge)
244                 do_merge=t
245                 ;;
246         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
247                 --strateg=*|--strategy=*|\
248         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
249                 case "$#,$1" in
250                 *,*=*)
251                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
252                 1,*)
253                         usage ;;
254                 *)
255                         strategy="$2"
256                         shift ;;
257                 esac
258                 do_merge=t
259                 ;;
260         -v|--verbose)
261                 verbose=t
262                 ;;
263         --whitespace=*)
264                 git_am_opt="$git_am_opt $1"
265                 ;;
266         -C*)
267                 git_am_opt="$git_am_opt $1"
268                 ;;
269         -*)
270                 usage
271                 ;;
272         *)
273                 break
274                 ;;
275         esac
276         shift
277 done
278
279 # Make sure we do not have $GIT_DIR/rebase-apply
280 if test -z "$do_merge"
281 then
282         if mkdir "$GIT_DIR"/rebase-apply 2>/dev/null
283         then
284                 rmdir "$GIT_DIR"/rebase-apply
285         else
286                 echo >&2 '
287 It seems that I cannot create a rebase-apply directory, and
288 I wonder if you are in the middle of patch application or another
289 rebase.  If that is not the case, please
290         rm -fr '"$GIT_DIR"'/rebase-apply
291 and run me again.  I am stopping in case you still have something
292 valuable there.'
293                 exit 1
294         fi
295 else
296         if test -d "$dotest"
297         then
298                 die "previous rebase directory $dotest still exists." \
299                         'Try git rebase (--continue | --abort | --skip)'
300         fi
301 fi
302
303 # The tree must be really really clean.
304 git update-index --ignore-submodules --refresh || exit
305 diff=$(git diff-index --cached --name-status -r --ignore-submodules HEAD --)
306 case "$diff" in
307 ?*)     echo "cannot rebase: your index is not up-to-date"
308         echo "$diff"
309         exit 1
310         ;;
311 esac
312
313 # The upstream head must be given.  Make sure it is valid.
314 upstream_name="$1"
315 upstream=`git rev-parse --verify "${upstream_name}^0"` ||
316     die "invalid upstream $upstream_name"
317
318 # Make sure the branch to rebase onto is valid.
319 onto_name=${newbase-"$upstream_name"}
320 onto=$(git rev-parse --verify "${onto_name}^0") || exit
321
322 # If a hook exists, give it a chance to interrupt
323 if test -x "$GIT_DIR/hooks/pre-rebase"
324 then
325         "$GIT_DIR/hooks/pre-rebase" ${1+"$@"} || {
326                 echo >&2 "The pre-rebase hook refused to rebase."
327                 exit 1
328         }
329 fi
330
331 # If the branch to rebase is given, that is the branch we will rebase
332 # $branch_name -- branch being rebased, or HEAD (already detached)
333 # $orig_head -- commit object name of tip of the branch before rebasing
334 # $head_name -- refs/heads/<that-branch> or "detached HEAD"
335 switch_to=
336 case "$#" in
337 2)
338         # Is it "rebase other $branchname" or "rebase other $commit"?
339         branch_name="$2"
340         switch_to="$2"
341
342         if git show-ref --verify --quiet -- "refs/heads/$2" &&
343            branch=$(git rev-parse --verify "refs/heads/$2" 2>/dev/null)
344         then
345                 head_name="refs/heads/$2"
346         elif branch=$(git rev-parse --verify "$2" 2>/dev/null)
347         then
348                 head_name="detached HEAD"
349         else
350                 usage
351         fi
352         ;;
353 *)
354         # Do not need to switch branches, we are already on it.
355         if branch_name=`git symbolic-ref -q HEAD`
356         then
357                 head_name=$branch_name
358                 branch_name=`expr "z$branch_name" : 'zrefs/heads/\(.*\)'`
359         else
360                 head_name="detached HEAD"
361                 branch_name=HEAD ;# detached
362         fi
363         branch=$(git rev-parse --verify "${branch_name}^0") || exit
364         ;;
365 esac
366 orig_head=$branch
367
368 # Now we are rebasing commits $upstream..$branch on top of $onto
369
370 # Check if we are already based on $onto with linear history,
371 # but this should be done only when upstream and onto are the same.
372 mb=$(git merge-base "$onto" "$branch")
373 if test "$upstream" = "$onto" && test "$mb" = "$onto" &&
374         # linear history?
375         ! (git rev-list --parents "$onto".."$branch" | grep " .* ") > /dev/null
376 then
377         # Lazily switch to the target branch if needed...
378         test -z "$switch_to" || git checkout "$switch_to"
379         echo >&2 "Current branch $branch_name is up to date."
380         exit 0
381 fi
382
383 if test -n "$verbose"
384 then
385         echo "Changes from $mb to $onto:"
386         # We want color (if set), but no pager
387         GIT_PAGER='' git diff --stat --summary "$mb" "$onto"
388 fi
389
390 # Detach HEAD and reset the tree
391 echo "First, rewinding head to replay your work on top of it..."
392 git checkout -q "$onto^0" || die "could not detach HEAD"
393 git update-ref ORIG_HEAD $branch
394
395 # If the $onto is a proper descendant of the tip of the branch, then
396 # we just fast forwarded.
397 if test "$mb" = "$branch"
398 then
399         echo >&2 "Fast-forwarded $branch_name to $onto_name."
400         move_to_original_branch
401         exit 0
402 fi
403
404 if test -z "$do_merge"
405 then
406         git format-patch -k --stdout --full-index --ignore-if-in-upstream \
407                 "$upstream..$orig_head" |
408         git am $git_am_opt --rebasing --resolvemsg="$RESOLVEMSG" &&
409         move_to_original_branch
410         ret=$?
411         test 0 != $ret -a -d "$GIT_DIR"/rebase-apply &&
412                 echo $head_name > "$GIT_DIR"/rebase-apply/head-name &&
413                 echo $onto > "$GIT_DIR"/rebase-apply/onto &&
414                 echo $orig_head > "$GIT_DIR"/rebase-apply/orig-head
415         exit $ret
416 fi
417
418 # start doing a rebase with git-merge
419 # this is rename-aware if the recursive (default) strategy is used
420
421 mkdir -p "$dotest"
422 echo "$onto" > "$dotest/onto"
423 echo "$onto_name" > "$dotest/onto_name"
424 prev_head=$orig_head
425 echo "$prev_head" > "$dotest/prev_head"
426 echo "$orig_head" > "$dotest/orig-head"
427 echo "$head_name" > "$dotest/head-name"
428
429 msgnum=0
430 for cmt in `git rev-list --reverse --no-merges "$upstream..$orig_head"`
431 do
432         msgnum=$(($msgnum + 1))
433         echo "$cmt" > "$dotest/cmt.$msgnum"
434 done
435
436 echo 1 >"$dotest/msgnum"
437 echo $msgnum >"$dotest/end"
438
439 end=$msgnum
440 msgnum=1
441
442 while test "$msgnum" -le "$end"
443 do
444         call_merge "$msgnum"
445         continue_merge
446 done
447
448 finish_rb_merge