show-branch: usability updates.
[git/git.git] / git-merge.sh
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1#!/bin/sh
2#
3# Copyright (c) 2005 Junio C Hamano
4#
5
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6
7USAGE='[-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+'
ae2b0f15 8. git-sh-setup
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9
10LF='
11'
12
64da9e60 13all_strategies='recursive octopus resolve stupid ours'
fbf8ac21 14default_strategies='recursive'
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15use_strategies=
16
a9358240 17dropsave() {
deca7e8c 18 rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
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19 "$GIT_DIR/MERGE_SAVE" || exit 1
20}
21
22savestate() {
60fa0560 23 # Stash away any local modifications.
50b8e355 24 git-diff-index -z --name-only $head |
88f8f0a5 25 cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
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26}
27
28restorestate() {
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29 if test -f "$GIT_DIR/MERGE_SAVE"
30 then
31 git reset --hard $head
32 cpio -iuv <"$GIT_DIR/MERGE_SAVE"
33 git-update-index --refresh >/dev/null
34 fi
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35}
36
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37finish () {
38 test '' = "$2" || echo "$2"
39 case "$merge_msg" in
40 '')
41 echo "No merge message -- not updating HEAD"
42 ;;
43 *)
44 git-update-ref HEAD "$1" "$head" || exit 1
45 ;;
46 esac
47
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48 case "$no_summary" in
49 '')
4f692b19 50 git-diff-tree -p -M "$head" "$1" |
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51 git-apply --stat --summary
52 ;;
53 esac
54}
55
56while case "$#" in 0) break ;; esac
57do
58 case "$1" in
59 -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
60 --no-summa|--no-summar|--no-summary)
61 no_summary=t ;;
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62 --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
63 no_commit=t ;;
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64 -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
65 --strateg=*|--strategy=*|\
66 -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
67 case "$#,$1" in
68 *,*=*)
69 strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
f88ed172 70 1,*)
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71 usage ;;
72 *)
73 strategy="$2"
74 shift ;;
75 esac
76 case " $all_strategies " in
77 *" $strategy "*)
78 use_strategies="$use_strategies$strategy " ;;
79 *)
80 die "available strategies are: $all_strategies" ;;
81 esac
82 ;;
83 -*) usage ;;
84 *) break ;;
85 esac
86 shift
87done
88
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89test "$#" -le 2 && usage ;# we need at least two heads.
90
91merge_msg="$1"
92shift
8cc01e50 93head_arg="$1"
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94head=$(git-rev-parse --verify "$1"^0) || usage
95shift
96
97# All the rest are remote heads
9954f5b8 98remoteheads=
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99for remote
100do
9954f5b8 101 remotehead=$(git-rev-parse --verify "$remote"^0) ||
91063bbc 102 die "$remote - not something we can merge"
9954f5b8 103 remoteheads="${remoteheads}$remotehead "
91063bbc 104done
9954f5b8 105set x $remoteheads ; shift
91063bbc 106
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107case "$#" in
1081)
109 common=$(git-merge-base --all $head "$@")
110 ;;
111*)
112 common=$(git-show-branch --merge-base $head "$@")
113 ;;
114esac
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115echo "$head" >"$GIT_DIR/ORIG_HEAD"
116
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117case "$#,$common,$no_commit" in
118*,'',*)
88f8f0a5 119 # No common ancestors found. We need a real merge.
91063bbc 120 ;;
123ee3ca 1211,"$1",*)
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122 # If head can reach all the merge then we are up to date.
123 # but first the most common case of merging one remote
4f692b19 124 echo "Already up-to-date."
a9358240 125 dropsave
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126 exit 0
127 ;;
123ee3ca 1281,"$head",*)
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129 # Again the most common case of merging one remote.
130 echo "Updating from $head to $1."
131 git-update-index --refresh 2>/dev/null
bf7960eb 132 new_head=$(git-rev-parse --verify "$1^0") &&
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133 git-read-tree -u -m $head "$new_head" &&
134 finish "$new_head" "Fast forward"
a9358240 135 dropsave
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136 exit 0
137 ;;
123ee3ca 1381,?*"$LF"?*,*)
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139 # We are not doing octopus and not fast forward. Need a
140 # real merge.
141 ;;
123ee3ca 1421,*,)
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143 # We are not doing octopus, not fast forward, and have only
144 # one common. See if it is really trivial.
145 echo "Trying really trivial in-index merge..."
146 git-update-index --refresh 2>/dev/null
147 if git-read-tree --trivial -m -u $common $head "$1" &&
148 result_tree=$(git-write-tree)
149 then
150 echo "Wonderful."
151 result_commit=$(
152 echo "$merge_msg" |
153 git-commit-tree $result_tree -p HEAD -p "$1"
154 ) || exit
4f692b19 155 finish "$result_commit" "In-index merge"
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156 dropsave
157 exit 0
158 fi
159 echo "Nope."
160 ;;
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161*)
162 # An octopus. If we can reach all the remote we are up to date.
163 up_to_date=t
164 for remote
165 do
13956670 166 common_one=$(git-merge-base --all $head $remote)
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167 if test "$common_one" != "$remote"
168 then
169 up_to_date=f
170 break
171 fi
172 done
173 if test "$up_to_date" = t
174 then
175 echo "Already up-to-date. Yeeah!"
a9358240 176 dropsave
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177 exit 0
178 fi
179 ;;
180esac
181
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182case "$use_strategies" in
183'')
184 case "$#" in
185 1)
186 use_strategies="$default_strategies" ;;
187 *)
188 use_strategies=octopus ;;
189 esac
190 ;;
191esac
192
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193# At this point, we need a real merge. No matter what strategy
194# we use, it would operate on the index, possibly affecting the
195# working tree, and when resolved cleanly, have the desired tree
196# in the index -- this means that the index must be in sync with
60fa0560 197# the $head commit. The strategies are responsible to ensure this.
91063bbc 198
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199case "$use_strategies" in
200?*' '?*)
201 # Stash away the local changes so that we can try more than one.
202 savestate
203 single_strategy=no
204 ;;
205*)
deca7e8c 206 rm -f "$GIT_DIR/MERGE_SAVE"
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207 single_strategy=yes
208 ;;
209esac
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210
211result_tree= best_cnt=-1 best_strategy= wt_strategy=
212for strategy in $use_strategies
213do
214 test "$wt_strategy" = '' || {
215 echo "Rewinding the tree to pristine..."
a9358240 216 restorestate
91063bbc 217 }
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218 case "$single_strategy" in
219 no)
220 echo "Trying merge strategy $strategy..."
221 ;;
222 esac
223
224 # Remember which strategy left the state in the working tree
91063bbc 225 wt_strategy=$strategy
a9358240 226
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227 git-merge-$strategy $common -- "$head_arg" "$@"
228 exit=$?
229 if test "$no_commit" = t && test "$exit" = 0
230 then
231 exit=1 ;# pretend it left conflicts.
232 fi
233
234 test "$exit" = 0 || {
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235
236 # The backend exits with 1 when conflicts are left to be resolved,
237 # with 2 when it does not handle the given merge at all.
238
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239 if test "$exit" -eq 1
240 then
241 cnt=`{
242 git-diff-files --name-only
243 git-ls-files --unmerged
244 } | wc -l`
245 if test $best_cnt -le 0 -o $cnt -le $best_cnt
246 then
247 best_strategy=$strategy
248 best_cnt=$cnt
249 fi
250 fi
251 continue
252 }
253
254 # Automerge succeeded.
255 result_tree=$(git-write-tree) && break
256done
257
258# If we have a resulting tree, that means the strategy module
259# auto resolved the merge cleanly.
260if test '' != "$result_tree"
261then
262 parents="-p $head"
263 for remote
264 do
265 parents="$parents -p $remote"
266 done
bf7960eb 267 result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
4f692b19 268 finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
a9358240 269 dropsave
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270 exit 0
271fi
272
273# Pick the result from the best strategy and have the user fix it up.
274case "$best_strategy" in
275'')
a9358240 276 restorestate
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277 echo >&2 "No merge strategy handled the merge."
278 exit 2
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279 ;;
280"$wt_strategy")
281 # We already have its result in the working tree.
282 ;;
283*)
284 echo "Rewinding the tree to pristine..."
a9358240 285 restorestate
91063bbc 286 echo "Using the $best_strategy to prepare resolving by hand."
a9358240 287 git-merge-$best_strategy $common -- "$head_arg" "$@"
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288 ;;
289esac
290for remote
291do
292 echo $remote
293done >"$GIT_DIR/MERGE_HEAD"
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294echo $merge_msg >"$GIT_DIR/MERGE_MSG"
295
123ee3ca 296die "Automatic merge failed/prevented; fix up by hand"