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