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