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[git.git] / git-merge.sh
blobb9f05192d1122df13f134b361887060ea042180c
1 #!/bin/sh
3 # Copyright (c) 2005 Junio C Hamano
6 USAGE='[-n] [--summary] [--[no-]commit] [--[no-]squash] [--[no-]ff] [-s <strategy>] [-m=<merge-message>] <commit>+'
8 SUBDIRECTORY_OK=Yes
9 . git-sh-setup
10 require_work_tree
11 cd_to_toplevel
13 test -z "$(git ls-files -u)" ||
14 die "You are in the middle of a conflicted merge."
16 LF='
19 all_strategies='recur recursive octopus resolve stupid ours subtree'
20 default_twohead_strategies='recursive'
21 default_octopus_strategies='octopus'
22 no_fast_forward_strategies='subtree ours'
23 no_trivial_strategies='recursive recur subtree ours'
24 use_strategies=
26 allow_fast_forward=t
27 allow_trivial_merge=t
29 dropsave() {
30 rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
31 "$GIT_DIR/MERGE_STASH" || exit 1
34 savestate() {
35 # Stash away any local modifications.
36 git stash create >"$GIT_DIR/MERGE_STASH"
39 restorestate() {
40 if test -f "$GIT_DIR/MERGE_STASH"
41 then
42 git reset --hard $head >/dev/null
43 git stash apply $(cat "$GIT_DIR/MERGE_STASH")
44 git update-index --refresh >/dev/null
48 finish_up_to_date () {
49 case "$squash" in
51 echo "$1 (nothing to squash)" ;;
52 '')
53 echo "$1" ;;
54 esac
55 dropsave
58 squash_message () {
59 echo Squashed commit of the following:
60 echo
61 git log --no-merges ^"$head" $remoteheads
64 finish () {
65 if test '' = "$2"
66 then
67 rlogm="$GIT_REFLOG_ACTION"
68 else
69 echo "$2"
70 rlogm="$GIT_REFLOG_ACTION: $2"
72 case "$squash" in
74 echo "Squash commit -- not updating HEAD"
75 squash_message >"$GIT_DIR/SQUASH_MSG"
77 '')
78 case "$merge_msg" in
79 '')
80 echo "No merge message -- not updating HEAD"
83 git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
84 git gc --auto
86 esac
88 esac
89 case "$1" in
90 '')
92 ?*)
93 if test "$show_diffstat" = t
94 then
95 # We want color (if set), but no pager
96 GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
99 esac
101 # Run a post-merge hook
102 if test -x "$GIT_DIR"/hooks/post-merge
103 then
104 case "$squash" in
106 "$GIT_DIR"/hooks/post-merge 1
109 "$GIT_DIR"/hooks/post-merge 0
111 esac
115 merge_name () {
116 remote="$1"
117 rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
118 bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
119 if test "$rh" = "$bh"
120 then
121 echo "$rh branch '$remote' of ."
122 elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
123 git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
124 then
125 echo "$rh branch '$truname' (early part) of ."
126 elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
127 then
128 sed -e 's/ not-for-merge / /' -e 1q \
129 "$GIT_DIR/FETCH_HEAD"
130 else
131 echo "$rh commit '$remote'"
135 parse_option () {
136 case "$1" in
137 -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
138 --no-summa|--no-summar|--no-summary)
139 show_diffstat=false ;;
140 --summary)
141 show_diffstat=t ;;
142 --sq|--squ|--squa|--squas|--squash)
143 allow_fast_forward=t squash=t no_commit=t ;;
144 --no-sq|--no-squ|--no-squa|--no-squas|--no-squash)
145 allow_fast_forward=t squash= no_commit= ;;
146 --c|--co|--com|--comm|--commi|--commit)
147 allow_fast_forward=t squash= no_commit= ;;
148 --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
149 allow_fast_forward=t squash= no_commit=t ;;
150 --ff)
151 allow_fast_forward=t squash= no_commit= ;;
152 --no-ff)
153 allow_fast_forward=false squash= no_commit= ;;
154 -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
155 --strateg=*|--strategy=*|\
156 -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
157 case "$#,$1" in
158 *,*=*)
159 strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
160 1,*)
161 usage ;;
163 strategy="$2"
164 shift ;;
165 esac
166 case " $all_strategies " in
167 *" $strategy "*)
168 use_strategies="$use_strategies$strategy " ;;
170 die "available strategies are: $all_strategies" ;;
171 esac
173 -m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
174 merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
175 have_message=t
177 -m|--m|--me|--mes|--mess|--messa|--messag|--message)
178 shift
179 case "$#" in
180 1) usage ;;
181 esac
182 merge_msg="$1"
183 have_message=t
185 -*) usage ;;
186 *) return 1 ;;
187 esac
188 shift
189 args_left=$#
192 parse_config () {
193 while test $# -gt 0
195 parse_option "$@" || usage
196 while test $args_left -lt $#
198 shift
199 done
200 done
203 test $# != 0 || usage
205 have_message=
207 if branch=$(git-symbolic-ref -q HEAD)
208 then
209 mergeopts=$(git config "branch.${branch#refs/heads/}.mergeoptions")
210 if test -n "$mergeopts"
211 then
212 parse_config $mergeopts
216 while parse_option "$@"
218 while test $args_left -lt $#
220 shift
221 done
222 done
224 if test -z "$show_diffstat"; then
225 test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
226 test -z "$show_diffstat" && show_diffstat=t
229 # This could be traditional "merge <msg> HEAD <commit>..." and the
230 # way we can tell it is to see if the second token is HEAD, but some
231 # people might have misused the interface and used a committish that
232 # is the same as HEAD there instead. Traditional format never would
233 # have "-m" so it is an additional safety measure to check for it.
235 if test -z "$have_message" &&
236 second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
237 head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
238 test "$second_token" = "$head_commit"
239 then
240 merge_msg="$1"
241 shift
242 head_arg="$1"
243 shift
244 elif ! git rev-parse --verify HEAD >/dev/null 2>&1
245 then
246 # If the merged head is a valid one there is no reason to
247 # forbid "git merge" into a branch yet to be born. We do
248 # the same for "git pull".
249 if test 1 -ne $#
250 then
251 echo >&2 "Can merge only exactly one commit into empty head"
252 exit 1
255 rh=$(git rev-parse --verify "$1^0") ||
256 die "$1 - not something we can merge"
258 git update-ref -m "initial pull" HEAD "$rh" "" &&
259 git read-tree --reset -u HEAD
260 exit
262 else
263 # We are invoked directly as the first-class UI.
264 head_arg=HEAD
266 # All the rest are the commits being merged; prepare
267 # the standard merge summary message to be appended to
268 # the given message. If remote is invalid we will die
269 # later in the common codepath so we discard the error
270 # in this loop.
271 merge_name=$(for remote
273 merge_name "$remote"
274 done | git fmt-merge-msg
276 merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
278 head=$(git rev-parse --verify "$head_arg"^0) || usage
280 # All the rest are remote heads
281 test "$#" = 0 && usage ;# we need at least one remote head.
282 set_reflog_action "merge $*"
284 remoteheads=
285 for remote
287 remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
288 die "$remote - not something we can merge"
289 remoteheads="${remoteheads}$remotehead "
290 eval GITHEAD_$remotehead='"$remote"'
291 export GITHEAD_$remotehead
292 done
293 set x $remoteheads ; shift
295 case "$use_strategies" in
297 case "$#" in
299 var="`git config --get pull.twohead`"
300 if test -n "$var"
301 then
302 use_strategies="$var"
303 else
304 use_strategies="$default_twohead_strategies"
305 fi ;;
307 var="`git config --get pull.octopus`"
308 if test -n "$var"
309 then
310 use_strategies="$var"
311 else
312 use_strategies="$default_octopus_strategies"
313 fi ;;
314 esac
316 esac
318 for s in $use_strategies
320 for ss in $no_fast_forward_strategies
322 case " $s " in
323 *" $ss "*)
324 allow_fast_forward=f
325 break
327 esac
328 done
329 for ss in $no_trivial_strategies
331 case " $s " in
332 *" $ss "*)
333 allow_trivial_merge=f
334 break
336 esac
337 done
338 done
340 case "$#" in
342 common=$(git merge-base --all $head "$@")
345 common=$(git show-branch --merge-base $head "$@")
347 esac
348 echo "$head" >"$GIT_DIR/ORIG_HEAD"
350 case "$allow_fast_forward,$#,$common,$no_commit" in
351 ?,*,'',*)
352 # No common ancestors found. We need a real merge.
354 ?,1,"$1",*)
355 # If head can reach all the merge then we are up to date.
356 # but first the most common case of merging one remote.
357 finish_up_to_date "Already up-to-date."
358 exit 0
360 t,1,"$head",*)
361 # Again the most common case of merging one remote.
362 echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
363 git update-index --refresh 2>/dev/null
364 msg="Fast forward"
365 if test -n "$have_message"
366 then
367 msg="$msg (no commit created; -m option ignored)"
369 new_head=$(git rev-parse --verify "$1^0") &&
370 git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
371 finish "$new_head" "$msg" || exit
372 dropsave
373 exit 0
375 ?,1,?*"$LF"?*,*)
376 # We are not doing octopus and not fast forward. Need a
377 # real merge.
379 ?,1,*,)
380 # We are not doing octopus, not fast forward, and have only
381 # one common.
382 git update-index --refresh 2>/dev/null
383 case "$allow_trivial_merge" in
385 # See if it is really trivial.
386 git var GIT_COMMITTER_IDENT >/dev/null || exit
387 echo "Trying really trivial in-index merge..."
388 if git read-tree --trivial -m -u -v $common $head "$1" &&
389 result_tree=$(git write-tree)
390 then
391 echo "Wonderful."
392 result_commit=$(
393 printf '%s\n' "$merge_msg" |
394 git commit-tree $result_tree -p HEAD -p "$1"
395 ) || exit
396 finish "$result_commit" "In-index merge"
397 dropsave
398 exit 0
400 echo "Nope."
401 esac
404 # An octopus. If we can reach all the remote we are up to date.
405 up_to_date=t
406 for remote
408 common_one=$(git merge-base --all $head $remote)
409 if test "$common_one" != "$remote"
410 then
411 up_to_date=f
412 break
414 done
415 if test "$up_to_date" = t
416 then
417 finish_up_to_date "Already up-to-date. Yeeah!"
418 exit 0
421 esac
423 # We are going to make a new commit.
424 git var GIT_COMMITTER_IDENT >/dev/null || exit
426 # At this point, we need a real merge. No matter what strategy
427 # we use, it would operate on the index, possibly affecting the
428 # working tree, and when resolved cleanly, have the desired tree
429 # in the index -- this means that the index must be in sync with
430 # the $head commit. The strategies are responsible to ensure this.
432 case "$use_strategies" in
433 ?*' '?*)
434 # Stash away the local changes so that we can try more than one.
435 savestate
436 single_strategy=no
439 rm -f "$GIT_DIR/MERGE_STASH"
440 single_strategy=yes
442 esac
444 result_tree= best_cnt=-1 best_strategy= wt_strategy=
445 merge_was_ok=
446 for strategy in $use_strategies
448 test "$wt_strategy" = '' || {
449 echo "Rewinding the tree to pristine..."
450 restorestate
452 case "$single_strategy" in
454 echo "Trying merge strategy $strategy..."
456 esac
458 # Remember which strategy left the state in the working tree
459 wt_strategy=$strategy
461 git-merge-$strategy $common -- "$head_arg" "$@"
462 exit=$?
463 if test "$no_commit" = t && test "$exit" = 0
464 then
465 merge_was_ok=t
466 exit=1 ;# pretend it left conflicts.
469 test "$exit" = 0 || {
471 # The backend exits with 1 when conflicts are left to be resolved,
472 # with 2 when it does not handle the given merge at all.
474 if test "$exit" -eq 1
475 then
476 cnt=`{
477 git diff-files --name-only
478 git ls-files --unmerged
479 } | wc -l`
480 if test $best_cnt -le 0 -o $cnt -le $best_cnt
481 then
482 best_strategy=$strategy
483 best_cnt=$cnt
486 continue
489 # Automerge succeeded.
490 result_tree=$(git write-tree) && break
491 done
493 # If we have a resulting tree, that means the strategy module
494 # auto resolved the merge cleanly.
495 if test '' != "$result_tree"
496 then
497 if test "$allow_fast_forward" = "t"
498 then
499 parents=$(git show-branch --independent "$head" "$@")
500 else
501 parents=$(git rev-parse "$head" "$@")
503 parents=$(echo "$parents" | sed -e 's/^/-p /')
504 result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
505 finish "$result_commit" "Merge made by $wt_strategy."
506 dropsave
507 exit 0
510 # Pick the result from the best strategy and have the user fix it up.
511 case "$best_strategy" in
513 restorestate
514 case "$use_strategies" in
515 ?*' '?*)
516 echo >&2 "No merge strategy handled the merge."
519 echo >&2 "Merge with strategy $use_strategies failed."
521 esac
522 exit 2
524 "$wt_strategy")
525 # We already have its result in the working tree.
528 echo "Rewinding the tree to pristine..."
529 restorestate
530 echo "Using the $best_strategy to prepare resolving by hand."
531 git-merge-$best_strategy $common -- "$head_arg" "$@"
533 esac
535 if test "$squash" = t
536 then
537 finish
538 else
539 for remote
541 echo $remote
542 done >"$GIT_DIR/MERGE_HEAD"
543 printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
546 if test "$merge_was_ok" = t
547 then
548 echo >&2 \
549 "Automatic merge went well; stopped before committing as requested"
550 exit 0
551 else
553 echo '
554 Conflicts:
556 git ls-files --unmerged |
557 sed -e 's/^[^ ]* / /' |
558 uniq
559 } >>"$GIT_DIR/MERGE_MSG"
560 git rerere
561 die "Automatic merge failed; fix conflicts and then commit the result."