Merge branch 'master' into lj/refs
[git/git.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 from $head to $1"
201 git-update-index --refresh 2>/dev/null
202 new_head=$(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