A new merge stragety 'subtree'.
[git/git.git] / git-merge.sh
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1#!/bin/sh
2#
3# Copyright (c) 2005 Junio C Hamano
4#
5
f9474132 6USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'
17bcdad3 7
533b7039 8SUBDIRECTORY_OK=Yes
ae2b0f15 9. git-sh-setup
7eff28a9 10require_work_tree
533b7039 11cd_to_toplevel
91063bbc 12
d1014a17 13test -z "$(git ls-files -u)" ||
533b7039 14 die "You are in the middle of a conflicted merge."
d1014a17 15
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16LF='
17'
18
68faf689 19all_strategies='recur recursive octopus resolve stupid ours subtree'
a06f678e 20default_twohead_strategies='recursive'
6ea23343 21default_octopus_strategies='octopus'
68faf689 22no_trivial_merge_strategies='ours subtree'
91063bbc 23use_strategies=
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24
25index_merge=t
91063bbc 26
a9358240 27dropsave() {
deca7e8c 28 rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
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29 "$GIT_DIR/MERGE_SAVE" || exit 1
30}
31
32savestate() {
60fa0560 33 # Stash away any local modifications.
50b8e355 34 git-diff-index -z --name-only $head |
88f8f0a5 35 cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
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36}
37
38restorestate() {
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39 if test -f "$GIT_DIR/MERGE_SAVE"
40 then
228e2eb6 41 git reset --hard $head >/dev/null
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42 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
43 git-update-index --refresh >/dev/null
44 fi
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45}
46
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47finish_up_to_date () {
48 case "$squash" in
49 t)
50 echo "$1 (nothing to squash)" ;;
51 '')
52 echo "$1" ;;
53 esac
54 dropsave
55}
56
57squash_message () {
58 echo Squashed commit of the following:
59 echo
60 git-log --no-merges ^"$head" $remote
61}
62
4f692b19 63finish () {
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64 if test '' = "$2"
65 then
f9474132 66 rlogm="$GIT_REFLOG_ACTION"
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67 else
68 echo "$2"
f9474132 69 rlogm="$GIT_REFLOG_ACTION: $2"
e1447e38 70 fi
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71 case "$squash" in
72 t)
73 echo "Squash commit -- not updating HEAD"
74 squash_message >"$GIT_DIR/SQUASH_MSG"
4f692b19 75 ;;
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76 '')
77 case "$merge_msg" in
78 '')
79 echo "No merge message -- not updating HEAD"
80 ;;
81 *)
e1447e38 82 git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
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83 ;;
84 esac
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85 ;;
86 esac
7d0c6887 87 case "$1" in
91063bbc 88 '')
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89 ;;
90 ?*)
91 case "$no_summary" in
92 '')
93 git-diff-tree --stat --summary -M "$head" "$1"
94 ;;
95 esac
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96 ;;
97 esac
98}
99
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100merge_name () {
101 remote="$1"
102 rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
103 bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
104 if test "$rh" = "$bh"
105 then
106 echo "$rh branch '$remote' of ."
107 elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
108 git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
109 then
110 echo "$rh branch '$truname' (early part) of ."
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111 elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
112 then
113 sed -e 's/ not-for-merge / /' -e 1q \
114 "$GIT_DIR/FETCH_HEAD"
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115 else
116 echo "$rh commit '$remote'"
117 fi
118}
119
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120case "$#" in 0) usage ;; esac
121
f9474132 122have_message=
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123while case "$#" in 0) break ;; esac
124do
125 case "$1" in
126 -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
127 --no-summa|--no-summar|--no-summary)
128 no_summary=t ;;
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129 --sq|--squ|--squa|--squas|--squash)
130 squash=t no_commit=t ;;
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131 --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
132 no_commit=t ;;
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133 -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
134 --strateg=*|--strategy=*|\
135 -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
136 case "$#,$1" in
137 *,*=*)
8096fae7 138 strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
f88ed172 139 1,*)
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140 usage ;;
141 *)
142 strategy="$2"
143 shift ;;
144 esac
145 case " $all_strategies " in
146 *" $strategy "*)
147 use_strategies="$use_strategies$strategy " ;;
148 *)
149 die "available strategies are: $all_strategies" ;;
150 esac
151 ;;
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152 -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
153 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
154 have_message=t
155 ;;
156 -m|--m|--me|--mes|--mess|--messa|--messag|--message)
157 shift
158 case "$#" in
159 1) usage ;;
160 esac
161 merge_msg="$1"
162 have_message=t
163 ;;
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164 -*) usage ;;
165 *) break ;;
166 esac
167 shift
168done
169
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170# This could be traditional "merge <msg> HEAD <commit>..." and the
171# way we can tell it is to see if the second token is HEAD, but some
172# people might have misused the interface and used a committish that
173# is the same as HEAD there instead. Traditional format never would
174# have "-m" so it is an additional safety measure to check for it.
175
176if test -z "$have_message" &&
177 second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
178 head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
179 test "$second_token" = "$head_commit"
180then
181 merge_msg="$1"
182 shift
183 head_arg="$1"
184 shift
c1751616 185elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
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186then
187 # If the merged head is a valid one there is no reason to
188 # forbid "git merge" into a branch yet to be born. We do
189 # the same for "git pull".
190 if test 1 -ne $#
191 then
192 echo >&2 "Can merge only exactly one commit into empty head"
193 exit 1
194 fi
195
196 rh=$(git rev-parse --verify "$1^0") ||
197 die "$1 - not something we can merge"
198
199 git-update-ref -m "initial pull" HEAD "$rh" "" &&
200 git-read-tree --reset -u HEAD
201 exit
202
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203else
204 # We are invoked directly as the first-class UI.
205 head_arg=HEAD
206
207 # All the rest are the commits being merged; prepare
208 # the standard merge summary message to be appended to
209 # the given message. If remote is invalid we will die
210 # later in the common codepath so we discard the error
211 # in this loop.
212 merge_name=$(for remote
213 do
b1bfcae4 214 merge_name "$remote"
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215 done | git-fmt-merge-msg
216 )
217 merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
218fi
219head=$(git-rev-parse --verify "$head_arg"^0) || usage
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220
221# All the rest are remote heads
6ea23343 222test "$#" = 0 && usage ;# we need at least one remote head.
7f9acb2a 223set_reflog_action "merge $*"
6ea23343 224
9954f5b8 225remoteheads=
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226for remote
227do
51901e96 228 remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
91063bbc 229 die "$remote - not something we can merge"
9954f5b8 230 remoteheads="${remoteheads}$remotehead "
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231 eval GITHEAD_$remotehead='"$remote"'
232 export GITHEAD_$remotehead
91063bbc 233done
9954f5b8 234set x $remoteheads ; shift
91063bbc 235
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236case "$use_strategies" in
237'')
238 case "$#" in
239 1)
e0d10e1c 240 var="`git-config --get pull.twohead`"
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241 if test -n "$var"
242 then
243 use_strategies="$var"
244 else
245 use_strategies="$default_twohead_strategies"
246 fi ;;
6ea23343 247 *)
e0d10e1c 248 var="`git-config --get pull.octopus`"
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249 if test -n "$var"
250 then
251 use_strategies="$var"
252 else
253 use_strategies="$default_octopus_strategies"
254 fi ;;
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255 esac
256 ;;
257esac
258
259for s in $use_strategies
260do
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261 for nt in $no_trivial_merge_strategies
262 do
263 case " $s " in
264 *" $nt "*)
265 index_merge=f
266 break
267 ;;
268 esac
269 done
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270done
271
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272case "$#" in
2731)
274 common=$(git-merge-base --all $head "$@")
275 ;;
276*)
277 common=$(git-show-branch --merge-base $head "$@")
278 ;;
279esac
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280echo "$head" >"$GIT_DIR/ORIG_HEAD"
281
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282case "$index_merge,$#,$common,$no_commit" in
283f,*)
284 # We've been told not to try anything clever. Skip to real merge.
285 ;;
286?,*,'',*)
88f8f0a5 287 # No common ancestors found. We need a real merge.
91063bbc 288 ;;
6ea23343 289?,1,"$1",*)
91063bbc 290 # If head can reach all the merge then we are up to date.
6ea23343 291 # but first the most common case of merging one remote.
7d0c6887 292 finish_up_to_date "Already up-to-date."
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293 exit 0
294 ;;
6ea23343 295?,1,"$head",*)
91063bbc 296 # Again the most common case of merging one remote.
ba0ac36e 297 echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
91063bbc 298 git-update-index --refresh 2>/dev/null
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299 msg="Fast forward"
300 if test -n "$have_message"
301 then
302 msg="$msg (no commit created; -m option ignored)"
303 fi
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304 new_head=$(git-rev-parse --verify "$1^0") &&
305 git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
be242d57 306 finish "$new_head" "$msg" || exit
a9358240 307 dropsave
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308 exit 0
309 ;;
6ea23343 310?,1,?*"$LF"?*,*)
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311 # We are not doing octopus and not fast forward. Need a
312 # real merge.
313 ;;
6ea23343 314?,1,*,)
f9d72413 315 # We are not doing octopus, not fast forward, and have only
c82d7117 316 # one common.
f9d72413 317 git-update-index --refresh 2>/dev/null
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318 case " $use_strategies " in
319 *' recursive '*|*' recur '*)
320 : run merge later
321 ;;
322 *)
323 # See if it is really trivial.
324 git var GIT_COMMITTER_IDENT >/dev/null || exit
325 echo "Trying really trivial in-index merge..."
326 if git-read-tree --trivial -m -u -v $common $head "$1" &&
327 result_tree=$(git-write-tree)
328 then
329 echo "Wonderful."
330 result_commit=$(
331 echo "$merge_msg" |
332 git-commit-tree $result_tree -p HEAD -p "$1"
333 ) || exit
334 finish "$result_commit" "In-index merge"
335 dropsave
336 exit 0
337 fi
338 echo "Nope."
339 esac
f9d72413 340 ;;
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341*)
342 # An octopus. If we can reach all the remote we are up to date.
343 up_to_date=t
344 for remote
345 do
13956670 346 common_one=$(git-merge-base --all $head $remote)
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347 if test "$common_one" != "$remote"
348 then
349 up_to_date=f
350 break
351 fi
352 done
353 if test "$up_to_date" = t
354 then
7d0c6887 355 finish_up_to_date "Already up-to-date. Yeeah!"
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356 exit 0
357 fi
358 ;;
359esac
360
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361# We are going to make a new commit.
362git var GIT_COMMITTER_IDENT >/dev/null || exit
363
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364# At this point, we need a real merge. No matter what strategy
365# we use, it would operate on the index, possibly affecting the
366# working tree, and when resolved cleanly, have the desired tree
367# in the index -- this means that the index must be in sync with
60fa0560 368# the $head commit. The strategies are responsible to ensure this.
91063bbc 369
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370case "$use_strategies" in
371?*' '?*)
372 # Stash away the local changes so that we can try more than one.
373 savestate
374 single_strategy=no
375 ;;
376*)
deca7e8c 377 rm -f "$GIT_DIR/MERGE_SAVE"
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378 single_strategy=yes
379 ;;
380esac
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381
382result_tree= best_cnt=-1 best_strategy= wt_strategy=
695bf722 383merge_was_ok=
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384for strategy in $use_strategies
385do
386 test "$wt_strategy" = '' || {
387 echo "Rewinding the tree to pristine..."
a9358240 388 restorestate
91063bbc 389 }
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390 case "$single_strategy" in
391 no)
392 echo "Trying merge strategy $strategy..."
393 ;;
394 esac
395
396 # Remember which strategy left the state in the working tree
91063bbc 397 wt_strategy=$strategy
a9358240 398
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399 git-merge-$strategy $common -- "$head_arg" "$@"
400 exit=$?
401 if test "$no_commit" = t && test "$exit" = 0
402 then
695bf722 403 merge_was_ok=t
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404 exit=1 ;# pretend it left conflicts.
405 fi
406
407 test "$exit" = 0 || {
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408
409 # The backend exits with 1 when conflicts are left to be resolved,
410 # with 2 when it does not handle the given merge at all.
411
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412 if test "$exit" -eq 1
413 then
414 cnt=`{
415 git-diff-files --name-only
416 git-ls-files --unmerged
417 } | wc -l`
418 if test $best_cnt -le 0 -o $cnt -le $best_cnt
419 then
420 best_strategy=$strategy
421 best_cnt=$cnt
422 fi
423 fi
424 continue
425 }
426
427 # Automerge succeeded.
428 result_tree=$(git-write-tree) && break
429done
430
431# If we have a resulting tree, that means the strategy module
432# auto resolved the merge cleanly.
433if test '' != "$result_tree"
434then
6ea23343 435 parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
bf7960eb 436 result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
e1447e38 437 finish "$result_commit" "Merge made by $wt_strategy."
a9358240 438 dropsave
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439 exit 0
440fi
441
442# Pick the result from the best strategy and have the user fix it up.
443case "$best_strategy" in
444'')
a9358240 445 restorestate
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446 case "$use_strategies" in
447 ?*' '?*)
448 echo >&2 "No merge strategy handled the merge."
449 ;;
450 *)
451 echo >&2 "Merge with strategy $use_strategies failed."
452 ;;
453 esac
4275df51 454 exit 2
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455 ;;
456"$wt_strategy")
457 # We already have its result in the working tree.
458 ;;
459*)
460 echo "Rewinding the tree to pristine..."
a9358240 461 restorestate
91063bbc 462 echo "Using the $best_strategy to prepare resolving by hand."
a9358240 463 git-merge-$best_strategy $common -- "$head_arg" "$@"
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464 ;;
465esac
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466
467if test "$squash" = t
468then
469 finish
470else
471 for remote
472 do
473 echo $remote
474 done >"$GIT_DIR/MERGE_HEAD"
475 echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
476fi
deca7e8c 477
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478if test "$merge_was_ok" = t
479then
480 echo >&2 \
481 "Automatic merge went well; stopped before committing as requested"
482 exit 0
483else
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484 {
485 echo '
486Conflicts:
487'
488 git ls-files --unmerged |
489 sed -e 's/^[^ ]* / /' |
490 uniq
491 } >>"$GIT_DIR/MERGE_MSG"
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492 if test -d "$GIT_DIR/rr-cache"
493 then
494 git-rerere
495 fi
50ac7408 496 die "Automatic merge failed; fix conflicts and then commit the result."
695bf722 497fi