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