user-manual: add "quick start" as chapter 1
[git] / git-rebase.sh
1 #!/bin/sh
2 #
3 # Copyright (c) 2005 Junio C Hamano.
4 #
5
6 USAGE='[-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 .dotest working files, use the command
18 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.  You must be in the top
22 directory of your project to start (or continue) a rebase.
23
24 Example:       git-rebase master~1 topic
25
26         A---B---C topic                   A'\''--B'\''--C'\'' topic
27        /                   -->           /
28   D---E---F---G master          D---E---F---G master
29 '
30
31 SUBDIRECTORY_OK=Yes
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=$GIT_DIR/.dotest-merge
46 prec=4
47 verbose=
48
49 continue_merge () {
50         test -n "$prev_head" || die "prev_head must be defined"
51         test -d "$dotest" || die "$dotest directory does not exist"
52
53         unmerged=$(git-ls-files -u)
54         if test -n "$unmerged"
55         then
56                 echo "You still have unmerged paths in your index"
57                 echo "did you forget update-index?"
58                 die "$RESOLVEMSG"
59         fi
60
61         if test -n "`git-diff-index HEAD`"
62         then
63                 if ! git-commit -C "`cat $dotest/current`"
64                 then
65                         echo "Commit failed, please do not call \"git commit\""
66                         echo "directly, but instead do one of the following: "
67                         die "$RESOLVEMSG"
68                 fi
69                 printf "Committed: %0${prec}d" $msgnum
70         else
71                 printf "Already applied: %0${prec}d" $msgnum
72         fi
73         echo ' '`git-rev-list --pretty=oneline -1 HEAD | \
74                                 sed 's/^[a-f0-9]\+ //'`
75
76         prev_head=`git-rev-parse HEAD^0`
77         # save the resulting commit so we can read-tree on it later
78         echo "$prev_head" > "$dotest/prev_head"
79
80         # onto the next patch:
81         msgnum=$(($msgnum + 1))
82         echo "$msgnum" >"$dotest/msgnum"
83 }
84
85 call_merge () {
86         cmt="$(cat $dotest/cmt.$1)"
87         echo "$cmt" > "$dotest/current"
88         hd=$(git-rev-parse --verify HEAD)
89         cmt_name=$(git-symbolic-ref HEAD)
90         msgnum=$(cat $dotest/msgnum)
91         end=$(cat $dotest/end)
92         eval GITHEAD_$cmt='"${cmt_name##refs/heads/}~$(($end - $msgnum))"'
93         eval GITHEAD_$hd='"$(cat $dotest/onto_name)"'
94         export GITHEAD_$cmt GITHEAD_$hd
95         git-merge-$strategy "$cmt^" -- "$hd" "$cmt"
96         rv=$?
97         case "$rv" in
98         0)
99                 unset GITHEAD_$cmt GITHEAD_$hd
100                 return
101                 ;;
102         1)
103                 test -d "$GIT_DIR/rr-cache" && git-rerere
104                 die "$RESOLVEMSG"
105                 ;;
106         2)
107                 echo "Strategy: $rv $strategy failed, try another" 1>&2
108                 die "$RESOLVEMSG"
109                 ;;
110         *)
111                 die "Unknown exit code ($rv) from command:" \
112                         "git-merge-$strategy $cmt^ -- HEAD $cmt"
113                 ;;
114         esac
115 }
116
117 finish_rb_merge () {
118         rm -r "$dotest"
119         echo "All done."
120 }
121
122 while case "$#" in 0) break ;; esac
123 do
124         case "$1" in
125         --continue)
126                 diff=$(git-diff-files)
127                 case "$diff" in
128                 ?*)     echo "You must edit all merge conflicts and then"
129                         echo "mark them as resolved using git update-index"
130                         exit 1
131                         ;;
132                 esac
133                 if test -d "$dotest"
134                 then
135                         prev_head="`cat $dotest/prev_head`"
136                         end="`cat $dotest/end`"
137                         msgnum="`cat $dotest/msgnum`"
138                         onto="`cat $dotest/onto`"
139                         continue_merge
140                         while test "$msgnum" -le "$end"
141                         do
142                                 call_merge "$msgnum"
143                                 continue_merge
144                         done
145                         finish_rb_merge
146                         exit
147                 fi
148                 git am --resolved --3way --resolvemsg="$RESOLVEMSG"
149                 exit
150                 ;;
151         --skip)
152                 if test -d "$dotest"
153                 then
154                         if test -d "$GIT_DIR/rr-cache"
155                         then
156                                 git-rerere clear
157                         fi
158                         prev_head="`cat $dotest/prev_head`"
159                         end="`cat $dotest/end`"
160                         msgnum="`cat $dotest/msgnum`"
161                         msgnum=$(($msgnum + 1))
162                         onto="`cat $dotest/onto`"
163                         while test "$msgnum" -le "$end"
164                         do
165                                 call_merge "$msgnum"
166                                 continue_merge
167                         done
168                         finish_rb_merge
169                         exit
170                 fi
171                 git am -3 --skip --resolvemsg="$RESOLVEMSG"
172                 exit
173                 ;;
174         --abort)
175                 if test -d "$GIT_DIR/rr-cache"
176                 then
177                         git-rerere clear
178                 fi
179                 if test -d "$dotest"
180                 then
181                         rm -r "$dotest"
182                 elif test -d .dotest
183                 then
184                         rm -r .dotest
185                 else
186                         die "No rebase in progress?"
187                 fi
188                 git reset --hard ORIG_HEAD
189                 exit
190                 ;;
191         --onto)
192                 test 2 -le "$#" || usage
193                 newbase="$2"
194                 shift
195                 ;;
196         -M|-m|--m|--me|--mer|--merg|--merge)
197                 do_merge=t
198                 ;;
199         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
200                 --strateg=*|--strategy=*|\
201         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
202                 case "$#,$1" in
203                 *,*=*)
204                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
205                 1,*)
206                         usage ;;
207                 *)
208                         strategy="$2"
209                         shift ;;
210                 esac
211                 do_merge=t
212                 ;;
213         -v|--verbose)
214                 verbose=t
215                 ;;
216         -*)
217                 usage
218                 ;;
219         *)
220                 break
221                 ;;
222         esac
223         shift
224 done
225
226 # Make sure we do not have .dotest
227 if test -z "$do_merge"
228 then
229         if mkdir .dotest
230         then
231                 rmdir .dotest
232         else
233                 echo >&2 '
234 It seems that I cannot create a .dotest directory, and I wonder if you
235 are in the middle of patch application or another rebase.  If that is not
236 the case, please rm -fr .dotest and run me again.  I am stopping in case
237 you still have something valuable there.'
238                 exit 1
239         fi
240 else
241         if test -d "$dotest"
242         then
243                 die "previous dotest directory $dotest still exists." \
244                         'try git-rebase < --continue | --abort >'
245         fi
246 fi
247
248 # The tree must be really really clean.
249 git-update-index --refresh || exit
250 diff=$(git-diff-index --cached --name-status -r HEAD)
251 case "$diff" in
252 ?*)     echo "$diff"
253         exit 1
254         ;;
255 esac
256
257 # The upstream head must be given.  Make sure it is valid.
258 upstream_name="$1"
259 upstream=`git rev-parse --verify "${upstream_name}^0"` ||
260     die "invalid upstream $upstream_name"
261
262 # If a hook exists, give it a chance to interrupt
263 if test -x "$GIT_DIR/hooks/pre-rebase"
264 then
265         "$GIT_DIR/hooks/pre-rebase" ${1+"$@"} || {
266                 echo >&2 "The pre-rebase hook refused to rebase."
267                 exit 1
268         }
269 fi
270
271 # If the branch to rebase is given, first switch to it.
272 case "$#" in
273 2)
274         branch_name="$2"
275         git-checkout "$2" || usage
276         ;;
277 *)
278         branch_name=`git symbolic-ref HEAD` || die "No current branch"
279         branch_name=`expr "z$branch_name" : 'zrefs/heads/\(.*\)'`
280         ;;
281 esac
282 branch=$(git-rev-parse --verify "${branch_name}^0") || exit
283
284 # Make sure the branch to rebase onto is valid.
285 onto_name=${newbase-"$upstream_name"}
286 onto=$(git-rev-parse --verify "${onto_name}^0") || exit
287
288 # Now we are rebasing commits $upstream..$branch on top of $onto
289
290 # Check if we are already based on $onto, but this should be
291 # done only when upstream and onto are the same.
292 mb=$(git-merge-base "$onto" "$branch")
293 if test "$upstream" = "$onto" && test "$mb" = "$onto"
294 then
295         echo >&2 "Current branch $branch_name is up to date."
296         exit 0
297 fi
298
299 if test -n "$verbose"
300 then
301         echo "Changes from $mb to $onto:"
302         git-diff-tree --stat --summary "$mb" "$onto"
303 fi
304
305 # Rewind the head to "$onto"; this saves our current head in ORIG_HEAD.
306 echo "First, rewinding head to replay your work on top of it..."
307 git-reset --hard "$onto"
308
309 # If the $onto is a proper descendant of the tip of the branch, then
310 # we just fast forwarded.
311 if test "$mb" = "$branch"
312 then
313         echo >&2 "Fast-forwarded $branch_name to $onto_name."
314         exit 0
315 fi
316
317 if test -z "$do_merge"
318 then
319         git-format-patch -k --stdout --full-index --ignore-if-in-upstream "$upstream"..ORIG_HEAD |
320         git am --binary -3 -k --resolvemsg="$RESOLVEMSG"
321         exit $?
322 fi
323
324 # start doing a rebase with git-merge
325 # this is rename-aware if the recursive (default) strategy is used
326
327 mkdir -p "$dotest"
328 echo "$onto" > "$dotest/onto"
329 echo "$onto_name" > "$dotest/onto_name"
330 prev_head=`git-rev-parse HEAD^0`
331 echo "$prev_head" > "$dotest/prev_head"
332
333 msgnum=0
334 for cmt in `git-rev-list --no-merges "$upstream"..ORIG_HEAD \
335                         | @@PERL@@ -e 'print reverse <>'`
336 do
337         msgnum=$(($msgnum + 1))
338         echo "$cmt" > "$dotest/cmt.$msgnum"
339 done
340
341 echo 1 >"$dotest/msgnum"
342 echo $msgnum >"$dotest/end"
343
344 end=$msgnum
345 msgnum=1
346
347 while test "$msgnum" -le "$end"
348 do
349         call_merge "$msgnum"
350         continue_merge
351 done
352
353 finish_rb_merge