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