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[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 "$(git ls-files -u)" ||
533b7039 14 die "You are in the middle of a conflicted merge."
d1014a17 15
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16LF='
17'
18
7cdbff14 19all_strategies='recur recursive octopus resolve stupid ours'
a06f678e 20default_twohead_strategies='recursive'
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21default_octopus_strategies='octopus'
22no_trivial_merge_strategies='ours'
91063bbc 23use_strategies=
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24
25index_merge=t
91063bbc 26
a9358240 27dropsave() {
deca7e8c 28 rm -f -- "$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 ."
111 else
112 echo "$rh commit '$remote'"
113 fi
114}
115
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116case "$#" in 0) usage ;; esac
117
f9474132 118have_message=
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119while case "$#" in 0) break ;; esac
120do
121 case "$1" in
122 -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
123 --no-summa|--no-summar|--no-summary)
124 no_summary=t ;;
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125 --sq|--squ|--squa|--squas|--squash)
126 squash=t no_commit=t ;;
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127 --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
128 no_commit=t ;;
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129 -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
130 --strateg=*|--strategy=*|\
131 -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
132 case "$#,$1" in
133 *,*=*)
8096fae7 134 strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
f88ed172 135 1,*)
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136 usage ;;
137 *)
138 strategy="$2"
139 shift ;;
140 esac
141 case " $all_strategies " in
142 *" $strategy "*)
143 use_strategies="$use_strategies$strategy " ;;
144 *)
145 die "available strategies are: $all_strategies" ;;
146 esac
147 ;;
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148 -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
149 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
150 have_message=t
151 ;;
152 -m|--m|--me|--mes|--mess|--messa|--messag|--message)
153 shift
154 case "$#" in
155 1) usage ;;
156 esac
157 merge_msg="$1"
158 have_message=t
159 ;;
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160 -*) usage ;;
161 *) break ;;
162 esac
163 shift
164done
165
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166# This could be traditional "merge <msg> HEAD <commit>..." and the
167# way we can tell it is to see if the second token is HEAD, but some
168# people might have misused the interface and used a committish that
169# is the same as HEAD there instead. Traditional format never would
170# have "-m" so it is an additional safety measure to check for it.
171
172if test -z "$have_message" &&
173 second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
174 head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
175 test "$second_token" = "$head_commit"
176then
177 merge_msg="$1"
178 shift
179 head_arg="$1"
180 shift
c1751616 181elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
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182then
183 # If the merged head is a valid one there is no reason to
184 # forbid "git merge" into a branch yet to be born. We do
185 # the same for "git pull".
186 if test 1 -ne $#
187 then
188 echo >&2 "Can merge only exactly one commit into empty head"
189 exit 1
190 fi
191
192 rh=$(git rev-parse --verify "$1^0") ||
193 die "$1 - not something we can merge"
194
195 git-update-ref -m "initial pull" HEAD "$rh" "" &&
196 git-read-tree --reset -u HEAD
197 exit
198
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199else
200 # We are invoked directly as the first-class UI.
201 head_arg=HEAD
202
203 # All the rest are the commits being merged; prepare
204 # the standard merge summary message to be appended to
205 # the given message. If remote is invalid we will die
206 # later in the common codepath so we discard the error
207 # in this loop.
208 merge_name=$(for remote
209 do
b1bfcae4 210 merge_name "$remote"
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211 done | git-fmt-merge-msg
212 )
213 merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
214fi
215head=$(git-rev-parse --verify "$head_arg"^0) || usage
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216
217# All the rest are remote heads
6ea23343 218test "$#" = 0 && usage ;# we need at least one remote head.
7f9acb2a 219set_reflog_action "merge $*"
6ea23343 220
9954f5b8 221remoteheads=
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222for remote
223do
51901e96 224 remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
91063bbc 225 die "$remote - not something we can merge"
9954f5b8 226 remoteheads="${remoteheads}$remotehead "
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227 eval GITHEAD_$remotehead='"$remote"'
228 export GITHEAD_$remotehead
91063bbc 229done
9954f5b8 230set x $remoteheads ; shift
91063bbc 231
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232case "$use_strategies" in
233'')
234 case "$#" in
235 1)
e0d10e1c 236 var="`git-config --get pull.twohead`"
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237 if test -n "$var"
238 then
239 use_strategies="$var"
240 else
241 use_strategies="$default_twohead_strategies"
242 fi ;;
6ea23343 243 *)
e0d10e1c 244 var="`git-config --get pull.octopus`"
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245 if test -n "$var"
246 then
247 use_strategies="$var"
248 else
249 use_strategies="$default_octopus_strategies"
250 fi ;;
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251 esac
252 ;;
253esac
254
255for s in $use_strategies
256do
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257 for nt in $no_trivial_merge_strategies
258 do
259 case " $s " in
260 *" $nt "*)
261 index_merge=f
262 break
263 ;;
264 esac
265 done
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266done
267
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268case "$#" in
2691)
270 common=$(git-merge-base --all $head "$@")
271 ;;
272*)
273 common=$(git-show-branch --merge-base $head "$@")
274 ;;
275esac
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276echo "$head" >"$GIT_DIR/ORIG_HEAD"
277
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278case "$index_merge,$#,$common,$no_commit" in
279f,*)
280 # We've been told not to try anything clever. Skip to real merge.
281 ;;
282?,*,'',*)
88f8f0a5 283 # No common ancestors found. We need a real merge.
91063bbc 284 ;;
6ea23343 285?,1,"$1",*)
91063bbc 286 # If head can reach all the merge then we are up to date.
6ea23343 287 # but first the most common case of merging one remote.
7d0c6887 288 finish_up_to_date "Already up-to-date."
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289 exit 0
290 ;;
6ea23343 291?,1,"$head",*)
91063bbc 292 # Again the most common case of merging one remote.
ba0ac36e 293 echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
91063bbc 294 git-update-index --refresh 2>/dev/null
bf7960eb 295 new_head=$(git-rev-parse --verify "$1^0") &&
11271480 296 git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
7d79c860 297 finish "$new_head" "Fast forward" || exit
a9358240 298 dropsave
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299 exit 0
300 ;;
6ea23343 301?,1,?*"$LF"?*,*)
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302 # We are not doing octopus and not fast forward. Need a
303 # real merge.
304 ;;
6ea23343 305?,1,*,)
f9d72413 306 # We are not doing octopus, not fast forward, and have only
c82d7117 307 # one common.
f9d72413 308 git-update-index --refresh 2>/dev/null
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309 case " $use_strategies " in
310 *' recursive '*|*' recur '*)
311 : run merge later
312 ;;
313 *)
314 # See if it is really trivial.
315 git var GIT_COMMITTER_IDENT >/dev/null || exit
316 echo "Trying really trivial in-index merge..."
317 if git-read-tree --trivial -m -u -v $common $head "$1" &&
318 result_tree=$(git-write-tree)
319 then
320 echo "Wonderful."
321 result_commit=$(
322 echo "$merge_msg" |
323 git-commit-tree $result_tree -p HEAD -p "$1"
324 ) || exit
325 finish "$result_commit" "In-index merge"
326 dropsave
327 exit 0
328 fi
329 echo "Nope."
330 esac
f9d72413 331 ;;
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332*)
333 # An octopus. If we can reach all the remote we are up to date.
334 up_to_date=t
335 for remote
336 do
13956670 337 common_one=$(git-merge-base --all $head $remote)
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338 if test "$common_one" != "$remote"
339 then
340 up_to_date=f
341 break
342 fi
343 done
344 if test "$up_to_date" = t
345 then
7d0c6887 346 finish_up_to_date "Already up-to-date. Yeeah!"
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347 exit 0
348 fi
349 ;;
350esac
351
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352# We are going to make a new commit.
353git var GIT_COMMITTER_IDENT >/dev/null || exit
354
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355# At this point, we need a real merge. No matter what strategy
356# we use, it would operate on the index, possibly affecting the
357# working tree, and when resolved cleanly, have the desired tree
358# in the index -- this means that the index must be in sync with
60fa0560 359# the $head commit. The strategies are responsible to ensure this.
91063bbc 360
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361case "$use_strategies" in
362?*' '?*)
363 # Stash away the local changes so that we can try more than one.
364 savestate
365 single_strategy=no
366 ;;
367*)
deca7e8c 368 rm -f "$GIT_DIR/MERGE_SAVE"
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369 single_strategy=yes
370 ;;
371esac
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372
373result_tree= best_cnt=-1 best_strategy= wt_strategy=
695bf722 374merge_was_ok=
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375for strategy in $use_strategies
376do
377 test "$wt_strategy" = '' || {
378 echo "Rewinding the tree to pristine..."
a9358240 379 restorestate
91063bbc 380 }
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381 case "$single_strategy" in
382 no)
383 echo "Trying merge strategy $strategy..."
384 ;;
385 esac
386
387 # Remember which strategy left the state in the working tree
91063bbc 388 wt_strategy=$strategy
a9358240 389
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390 git-merge-$strategy $common -- "$head_arg" "$@"
391 exit=$?
392 if test "$no_commit" = t && test "$exit" = 0
393 then
695bf722 394 merge_was_ok=t
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395 exit=1 ;# pretend it left conflicts.
396 fi
397
398 test "$exit" = 0 || {
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399
400 # The backend exits with 1 when conflicts are left to be resolved,
401 # with 2 when it does not handle the given merge at all.
402
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403 if test "$exit" -eq 1
404 then
405 cnt=`{
406 git-diff-files --name-only
407 git-ls-files --unmerged
408 } | wc -l`
409 if test $best_cnt -le 0 -o $cnt -le $best_cnt
410 then
411 best_strategy=$strategy
412 best_cnt=$cnt
413 fi
414 fi
415 continue
416 }
417
418 # Automerge succeeded.
419 result_tree=$(git-write-tree) && break
420done
421
422# If we have a resulting tree, that means the strategy module
423# auto resolved the merge cleanly.
424if test '' != "$result_tree"
425then
6ea23343 426 parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
bf7960eb 427 result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
e1447e38 428 finish "$result_commit" "Merge made by $wt_strategy."
a9358240 429 dropsave
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430 exit 0
431fi
432
433# Pick the result from the best strategy and have the user fix it up.
434case "$best_strategy" in
435'')
a9358240 436 restorestate
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437 case "$use_strategies" in
438 ?*' '?*)
439 echo >&2 "No merge strategy handled the merge."
440 ;;
441 *)
442 echo >&2 "Merge with strategy $use_strategies failed."
443 ;;
444 esac
4275df51 445 exit 2
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446 ;;
447"$wt_strategy")
448 # We already have its result in the working tree.
449 ;;
450*)
451 echo "Rewinding the tree to pristine..."
a9358240 452 restorestate
91063bbc 453 echo "Using the $best_strategy to prepare resolving by hand."
a9358240 454 git-merge-$best_strategy $common -- "$head_arg" "$@"
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455 ;;
456esac
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457
458if test "$squash" = t
459then
460 finish
461else
462 for remote
463 do
464 echo $remote
465 done >"$GIT_DIR/MERGE_HEAD"
466 echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
467fi
deca7e8c 468
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469if test "$merge_was_ok" = t
470then
471 echo >&2 \
472 "Automatic merge went well; stopped before committing as requested"
473 exit 0
474else
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475 {
476 echo '
477Conflicts:
478'
479 git ls-files --unmerged |
480 sed -e 's/^[^ ]* / /' |
481 uniq
482 } >>"$GIT_DIR/MERGE_MSG"
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483 if test -d "$GIT_DIR/rr-cache"
484 then
485 git-rerere
486 fi
50ac7408 487 die "Automatic merge failed; fix conflicts and then commit the result."
695bf722 488fi