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