Merge branch 'hold/svn'
[git/git.git] / git-merge.sh
CommitLineData
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1#!/bin/sh
2#
3# Copyright (c) 2005 Junio C Hamano
4#
5
6. git-sh-setup || die "Not a git archive"
7
8LF='
9'
10
11usage () {
123ee3ca 12 die "git-merge [-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+"
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13}
14
e4cf17ce 15# all_strategies='resolve recursive stupid octopus'
91063bbc 16
64da9e60 17all_strategies='recursive octopus resolve stupid ours'
2276aa6c 18default_strategies='resolve octopus'
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19use_strategies=
20
a9358240 21dropsave() {
deca7e8c 22 rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
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23 "$GIT_DIR/MERGE_SAVE" || exit 1
24}
25
26savestate() {
60fa0560 27 # Stash away any local modifications.
50b8e355 28 git-diff-index -z --name-only $head |
88f8f0a5 29 cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
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30}
31
32restorestate() {
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33 if test -f "$GIT_DIR/MERGE_SAVE"
34 then
35 git reset --hard $head
36 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
37 git-update-index --refresh >/dev/null
38 fi
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39}
40
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41finish () {
42 test '' = "$2" || echo "$2"
43 case "$merge_msg" in
44 '')
45 echo "No merge message -- not updating HEAD"
46 ;;
47 *)
48 git-update-ref HEAD "$1" "$head" || exit 1
49 ;;
50 esac
51
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52 case "$no_summary" in
53 '')
4f692b19 54 git-diff-tree -p -M "$head" "$1" |
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55 git-apply --stat --summary
56 ;;
57 esac
58}
59
60while case "$#" in 0) break ;; esac
61do
62 case "$1" in
63 -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
64 --no-summa|--no-summar|--no-summary)
65 no_summary=t ;;
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66 --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
67 no_commit=t ;;
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68 -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
69 --strateg=*|--strategy=*|\
70 -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
71 case "$#,$1" in
72 *,*=*)
73 strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
f88ed172 74 1,*)
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75 usage ;;
76 *)
77 strategy="$2"
78 shift ;;
79 esac
80 case " $all_strategies " in
81 *" $strategy "*)
82 use_strategies="$use_strategies$strategy " ;;
83 *)
84 die "available strategies are: $all_strategies" ;;
85 esac
86 ;;
87 -*) usage ;;
88 *) break ;;
89 esac
90 shift
91done
92
93case "$use_strategies" in
94'')
95 use_strategies=$default_strategies
96 ;;
97esac
98test "$#" -le 2 && usage ;# we need at least two heads.
99
100merge_msg="$1"
101shift
8cc01e50 102head_arg="$1"
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103head=$(git-rev-parse --verify "$1"^0) || usage
104shift
105
106# All the rest are remote heads
107for remote
108do
109 git-rev-parse --verify "$remote"^0 >/dev/null ||
110 die "$remote - not something we can merge"
111done
112
113common=$(git-show-branch --merge-base $head "$@")
114echo "$head" >"$GIT_DIR/ORIG_HEAD"
115
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116case "$#,$common,$no_commit" in
117*,'',*)
88f8f0a5 118 # No common ancestors found. We need a real merge.
91063bbc 119 ;;
123ee3ca 1201,"$1",*)
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121 # If head can reach all the merge then we are up to date.
122 # but first the most common case of merging one remote
4f692b19 123 echo "Already up-to-date."
a9358240 124 dropsave
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125 exit 0
126 ;;
123ee3ca 1271,"$head",*)
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128 # Again the most common case of merging one remote.
129 echo "Updating from $head to $1."
130 git-update-index --refresh 2>/dev/null
bf7960eb 131 new_head=$(git-rev-parse --verify "$1^0") &&
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132 git-read-tree -u -m $head "$new_head" &&
133 finish "$new_head" "Fast forward"
a9358240 134 dropsave
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135 exit 0
136 ;;
123ee3ca 1371,?*"$LF"?*,*)
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138 # We are not doing octopus and not fast forward. Need a
139 # real merge.
140 ;;
123ee3ca 1411,*,)
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142 # We are not doing octopus, not fast forward, and have only
143 # one common. See if it is really trivial.
144 echo "Trying really trivial in-index merge..."
145 git-update-index --refresh 2>/dev/null
146 if git-read-tree --trivial -m -u $common $head "$1" &&
147 result_tree=$(git-write-tree)
148 then
149 echo "Wonderful."
150 result_commit=$(
151 echo "$merge_msg" |
152 git-commit-tree $result_tree -p HEAD -p "$1"
153 ) || exit
4f692b19 154 finish "$result_commit" "In-index merge"
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155 dropsave
156 exit 0
157 fi
158 echo "Nope."
159 ;;
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160*)
161 # An octopus. If we can reach all the remote we are up to date.
162 up_to_date=t
163 for remote
164 do
165 common_one=$(git-merge-base $head $remote)
166 if test "$common_one" != "$remote"
167 then
168 up_to_date=f
169 break
170 fi
171 done
172 if test "$up_to_date" = t
173 then
174 echo "Already up-to-date. Yeeah!"
a9358240 175 dropsave
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176 exit 0
177 fi
178 ;;
179esac
180
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181# At this point, we need a real merge. No matter what strategy
182# we use, it would operate on the index, possibly affecting the
183# working tree, and when resolved cleanly, have the desired tree
184# in the index -- this means that the index must be in sync with
60fa0560 185# the $head commit. The strategies are responsible to ensure this.
91063bbc 186
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187case "$use_strategies" in
188?*' '?*)
189 # Stash away the local changes so that we can try more than one.
190 savestate
191 single_strategy=no
192 ;;
193*)
deca7e8c 194 rm -f "$GIT_DIR/MERGE_SAVE"
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195 single_strategy=yes
196 ;;
197esac
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198
199result_tree= best_cnt=-1 best_strategy= wt_strategy=
200for strategy in $use_strategies
201do
202 test "$wt_strategy" = '' || {
203 echo "Rewinding the tree to pristine..."
a9358240 204 restorestate
91063bbc 205 }
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206 case "$single_strategy" in
207 no)
208 echo "Trying merge strategy $strategy..."
209 ;;
210 esac
211
212 # Remember which strategy left the state in the working tree
91063bbc 213 wt_strategy=$strategy
a9358240 214
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215 git-merge-$strategy $common -- "$head_arg" "$@"
216 exit=$?
217 if test "$no_commit" = t && test "$exit" = 0
218 then
219 exit=1 ;# pretend it left conflicts.
220 fi
221
222 test "$exit" = 0 || {
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223
224 # The backend exits with 1 when conflicts are left to be resolved,
225 # with 2 when it does not handle the given merge at all.
226
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227 if test "$exit" -eq 1
228 then
229 cnt=`{
230 git-diff-files --name-only
231 git-ls-files --unmerged
232 } | wc -l`
233 if test $best_cnt -le 0 -o $cnt -le $best_cnt
234 then
235 best_strategy=$strategy
236 best_cnt=$cnt
237 fi
238 fi
239 continue
240 }
241
242 # Automerge succeeded.
243 result_tree=$(git-write-tree) && break
244done
245
246# If we have a resulting tree, that means the strategy module
247# auto resolved the merge cleanly.
248if test '' != "$result_tree"
249then
250 parents="-p $head"
251 for remote
252 do
253 parents="$parents -p $remote"
254 done
bf7960eb 255 result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
4f692b19 256 finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
a9358240 257 dropsave
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258 exit 0
259fi
260
261# Pick the result from the best strategy and have the user fix it up.
262case "$best_strategy" in
263'')
a9358240 264 restorestate
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265 die "No merge strategy handled the merge."
266 ;;
267"$wt_strategy")
268 # We already have its result in the working tree.
269 ;;
270*)
271 echo "Rewinding the tree to pristine..."
a9358240 272 restorestate
91063bbc 273 echo "Using the $best_strategy to prepare resolving by hand."
a9358240 274 git-merge-$best_strategy $common -- "$head_arg" "$@"
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275 ;;
276esac
277for remote
278do
279 echo $remote
280done >"$GIT_DIR/MERGE_HEAD"
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281echo $merge_msg >"$GIT_DIR/MERGE_MSG"
282
123ee3ca 283die "Automatic merge failed/prevented; fix up by hand"