Merge branch 'master' into js/c-merge-recursive
[git] / git-merge.sh
1 #!/bin/sh
2 #
3 # Copyright (c) 2005 Junio C Hamano
4 #
5
6 USAGE='[-n] [--no-commit] [--squash] [-s <strategy>]... <merge-message> <head> <remote>+'
7 . git-sh-setup
8
9 LF='
10 '
11
12 all_strategies='recursive recur octopus resolve stupid ours'
13 case "${GIT_USE_RECUR_FOR_RECURSIVE}" in
14 '')
15         default_twohead_strategies=recursive ;;
16 ?*)
17         default_twohead_strategies=recur ;;
18 esac
19 default_octopus_strategies='octopus'
20 no_trivial_merge_strategies='ours'
21 use_strategies=
22
23 index_merge=t
24 if test "@@NO_PYTHON@@"; then
25         all_strategies='recur resolve octopus stupid ours'
26         default_twohead_strategies='resolve'
27 fi
28
29 dropsave() {
30         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
31                  "$GIT_DIR/MERGE_SAVE" || exit 1
32 }
33
34 savestate() {
35         # Stash away any local modifications.
36         git-diff-index -z --name-only $head |
37         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
38 }
39
40 restorestate() {
41         if test -f "$GIT_DIR/MERGE_SAVE"
42         then
43                 git reset --hard $head
44                 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
45                 git-update-index --refresh >/dev/null
46         fi
47 }
48
49 finish_up_to_date () {
50         case "$squash" in
51         t)
52                 echo "$1 (nothing to squash)" ;;
53         '')
54                 echo "$1" ;;
55         esac
56         dropsave
57 }
58
59 squash_message () {
60         echo Squashed commit of the following:
61         echo
62         git-log --no-merges ^"$head" $remote
63 }
64
65 finish () {
66         if test '' = "$2"
67         then
68                 rlogm="$rloga"
69         else
70                 echo "$2"
71                 rlogm="$rloga: $2"
72         fi
73         case "$squash" in
74         t)
75                 echo "Squash commit -- not updating HEAD"
76                 squash_message >"$GIT_DIR/SQUASH_MSG"
77                 ;;
78         '')
79                 case "$merge_msg" in
80                 '')
81                         echo "No merge message -- not updating HEAD"
82                         ;;
83                 *)
84                         git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
85                         ;;
86                 esac
87                 ;;
88         esac
89         case "$1" in
90         '')
91                 ;;
92         ?*)
93                 case "$no_summary" in
94                 '')
95                         git-diff-tree --stat --summary -M "$head" "$1"
96                         ;;
97                 esac
98                 ;;
99         esac
100 }
101
102 rloga=
103 while case "$#" in 0) break ;; esac
104 do
105         case "$1" in
106         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
107                 --no-summa|--no-summar|--no-summary)
108                 no_summary=t ;;
109         --sq|--squ|--squa|--squas|--squash)
110                 squash=t no_commit=t ;;
111         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
112                 no_commit=t ;;
113         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
114                 --strateg=*|--strategy=*|\
115         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
116                 case "$#,$1" in
117                 *,*=*)
118                         strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
119                 1,*)
120                         usage ;;
121                 *)
122                         strategy="$2"
123                         shift ;;
124                 esac
125                 case "$strategy,${GIT_USE_RECUR_FOR_RECURSIVE}" in
126                 recursive,?*)
127                         strategy=recur ;;
128                 esac
129                 case " $all_strategies " in
130                 *" $strategy "*)
131                         use_strategies="$use_strategies$strategy " ;;
132                 *)
133                         die "available strategies are: $all_strategies" ;;
134                 esac
135                 ;;
136         --reflog-action=*)
137                 rloga=`expr "z$1" : 'z-[^=]*=\(.*\)'`
138                 ;;
139         -*)     usage ;;
140         *)      break ;;
141         esac
142         shift
143 done
144
145 merge_msg="$1"
146 shift
147 head_arg="$1"
148 head=$(git-rev-parse --verify "$1"^0) || usage
149 shift
150
151 # All the rest are remote heads
152 test "$#" = 0 && usage ;# we need at least one remote head.
153 test "$rloga" = '' && rloga="merge: $@"
154
155 remoteheads=
156 for remote
157 do
158         remotehead=$(git-rev-parse --verify "$remote"^0) ||
159             die "$remote - not something we can merge"
160         remoteheads="${remoteheads}$remotehead "
161 done
162 set x $remoteheads ; shift
163
164 case "$use_strategies" in
165 '')
166         case "$#" in
167         1)
168                 use_strategies="$default_twohead_strategies" ;;
169         *)
170                 use_strategies="$default_octopus_strategies" ;;
171         esac
172         ;;
173 esac
174
175 for s in $use_strategies
176 do
177         case " $s " in
178         *" $no_trivial_merge_strategies "*)
179                 index_merge=f
180                 break
181                 ;;
182         esac
183 done
184
185 case "$#" in
186 1)
187         common=$(git-merge-base --all $head "$@")
188         ;;
189 *)
190         common=$(git-show-branch --merge-base $head "$@")
191         ;;
192 esac
193 echo "$head" >"$GIT_DIR/ORIG_HEAD"
194
195 case "$index_merge,$#,$common,$no_commit" in
196 f,*)
197         # We've been told not to try anything clever.  Skip to real merge.
198         ;;
199 ?,*,'',*)
200         # No common ancestors found. We need a real merge.
201         ;;
202 ?,1,"$1",*)
203         # If head can reach all the merge then we are up to date.
204         # but first the most common case of merging one remote.
205         finish_up_to_date "Already up-to-date."
206         exit 0
207         ;;
208 ?,1,"$head",*)
209         # Again the most common case of merging one remote.
210         echo "Updating from $head to $1"
211         git-update-index --refresh 2>/dev/null
212         new_head=$(git-rev-parse --verify "$1^0") &&
213         git-read-tree -u -v -m $head "$new_head" &&
214         finish "$new_head" "Fast forward"
215         dropsave
216         exit 0
217         ;;
218 ?,1,?*"$LF"?*,*)
219         # We are not doing octopus and not fast forward.  Need a
220         # real merge.
221         ;;
222 ?,1,*,)
223         # We are not doing octopus, not fast forward, and have only
224         # one common.  See if it is really trivial.
225         git var GIT_COMMITTER_IDENT >/dev/null || exit
226
227         echo "Trying really trivial in-index merge..."
228         git-update-index --refresh 2>/dev/null
229         if git-read-tree --trivial -m -u -v $common $head "$1" &&
230            result_tree=$(git-write-tree)
231         then
232             echo "Wonderful."
233             result_commit=$(
234                 echo "$merge_msg" |
235                 git-commit-tree $result_tree -p HEAD -p "$1"
236             ) || exit
237             finish "$result_commit" "In-index merge"
238             dropsave
239             exit 0
240         fi
241         echo "Nope."
242         ;;
243 *)
244         # An octopus.  If we can reach all the remote we are up to date.
245         up_to_date=t
246         for remote
247         do
248                 common_one=$(git-merge-base --all $head $remote)
249                 if test "$common_one" != "$remote"
250                 then
251                         up_to_date=f
252                         break
253                 fi
254         done
255         if test "$up_to_date" = t
256         then
257                 finish_up_to_date "Already up-to-date. Yeeah!"
258                 exit 0
259         fi
260         ;;
261 esac
262
263 # We are going to make a new commit.
264 git var GIT_COMMITTER_IDENT >/dev/null || exit
265
266 # At this point, we need a real merge.  No matter what strategy
267 # we use, it would operate on the index, possibly affecting the
268 # working tree, and when resolved cleanly, have the desired tree
269 # in the index -- this means that the index must be in sync with
270 # the $head commit.  The strategies are responsible to ensure this.
271
272 case "$use_strategies" in
273 ?*' '?*)
274     # Stash away the local changes so that we can try more than one.
275     savestate
276     single_strategy=no
277     ;;
278 *)
279     rm -f "$GIT_DIR/MERGE_SAVE"
280     single_strategy=yes
281     ;;
282 esac
283
284 result_tree= best_cnt=-1 best_strategy= wt_strategy=
285 merge_was_ok=
286 for strategy in $use_strategies
287 do
288     test "$wt_strategy" = '' || {
289         echo "Rewinding the tree to pristine..."
290         restorestate
291     }
292     case "$single_strategy" in
293     no)
294         echo "Trying merge strategy $strategy..."
295         ;;
296     esac
297
298     # Remember which strategy left the state in the working tree
299     wt_strategy=$strategy
300
301     git-merge-$strategy $common -- "$head_arg" "$@"
302     exit=$?
303     if test "$no_commit" = t && test "$exit" = 0
304     then
305         merge_was_ok=t
306         exit=1 ;# pretend it left conflicts.
307     fi
308
309     test "$exit" = 0 || {
310
311         # The backend exits with 1 when conflicts are left to be resolved,
312         # with 2 when it does not handle the given merge at all.
313
314         if test "$exit" -eq 1
315         then
316             cnt=`{
317                 git-diff-files --name-only
318                 git-ls-files --unmerged
319             } | wc -l`
320             if test $best_cnt -le 0 -o $cnt -le $best_cnt
321             then
322                 best_strategy=$strategy
323                 best_cnt=$cnt
324             fi
325         fi
326         continue
327     }
328
329     # Automerge succeeded.
330     result_tree=$(git-write-tree) && break
331 done
332
333 # If we have a resulting tree, that means the strategy module
334 # auto resolved the merge cleanly.
335 if test '' != "$result_tree"
336 then
337     parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
338     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
339     finish "$result_commit" "Merge made by $wt_strategy."
340     dropsave
341     exit 0
342 fi
343
344 # Pick the result from the best strategy and have the user fix it up.
345 case "$best_strategy" in
346 '')
347         restorestate
348         echo >&2 "No merge strategy handled the merge."
349         exit 2
350         ;;
351 "$wt_strategy")
352         # We already have its result in the working tree.
353         ;;
354 *)
355         echo "Rewinding the tree to pristine..."
356         restorestate
357         echo "Using the $best_strategy to prepare resolving by hand."
358         git-merge-$best_strategy $common -- "$head_arg" "$@"
359         ;;
360 esac
361
362 if test "$squash" = t
363 then
364         finish
365 else
366         for remote
367         do
368                 echo $remote
369         done >"$GIT_DIR/MERGE_HEAD"
370         echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
371 fi
372
373 if test "$merge_was_ok" = t
374 then
375         echo >&2 \
376         "Automatic merge went well; stopped before committing as requested"
377         exit 0
378 else
379         {
380             echo '
381 Conflicts:
382 '
383                 git ls-files --unmerged |
384                 sed -e 's/^[^   ]*      /       /' |
385                 uniq
386         } >>"$GIT_DIR/MERGE_MSG"
387         if test -d "$GIT_DIR/rr-cache"
388         then
389                 git-rerere
390         fi
391         die "Automatic merge failed; fix conflicts and then commit the result."
392 fi