Keep Porcelainish from failing by broken ident after making changes.
[git] / git-merge.sh
1 #!/bin/sh
2 #
3 # Copyright (c) 2005 Junio C Hamano
4 #
5
6
7 USAGE='[-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+'
8 . git-sh-setup
9
10 LF='
11 '
12
13 all_strategies='recursive octopus resolve stupid ours'
14 default_strategies='recursive'
15 use_strategies=
16
17 dropsave() {
18         rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
19                  "$GIT_DIR/MERGE_SAVE" || exit 1
20 }
21
22 savestate() {
23         # Stash away any local modifications.
24         git-diff-index -z --name-only $head |
25         cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
26 }
27
28 restorestate() {
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
35 }
36
37 finish () {
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
48         case "$no_summary" in
49         '')
50                 git-diff-tree -p -M "$head" "$1" |
51                 git-apply --stat --summary
52                 ;;
53         esac
54 }
55
56 while case "$#" in 0) break ;; esac
57 do
58         case "$1" in
59         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
60                 --no-summa|--no-summar|--no-summary)
61                 no_summary=t ;;
62         --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
63                 no_commit=t ;;
64         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
65                 --strateg=*|--strategy=*|\
66         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
67                 case "$#,$1" in
68                 *,*=*)
69                         strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
70                 1,*)
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: $all_strategies" ;;
81                 esac
82                 ;;
83         -*)     usage ;;
84         *)      break ;;
85         esac
86         shift
87 done
88
89 test "$#" -le 2 && usage ;# we need at least two heads.
90
91 merge_msg="$1"
92 shift
93 head_arg="$1"
94 head=$(git-rev-parse --verify "$1"^0) || usage
95 shift
96
97 # All the rest are remote heads
98 remoteheads=
99 for remote
100 do
101         remotehead=$(git-rev-parse --verify "$remote"^0) ||
102             die "$remote - not something we can merge"
103         remoteheads="${remoteheads}$remotehead "
104 done
105 set x $remoteheads ; shift
106
107 case "$#" in
108 1)
109         common=$(git-merge-base --all $head "$@")
110         ;;
111 *)
112         common=$(git-show-branch --merge-base $head "$@")
113         ;;
114 esac
115 echo "$head" >"$GIT_DIR/ORIG_HEAD"
116
117 case "$#,$common,$no_commit" in
118 *,'',*)
119         # No common ancestors found. We need a real merge.
120         ;;
121 1,"$1",*)
122         # If head can reach all the merge then we are up to date.
123         # but first the most common case of merging one remote
124         echo "Already up-to-date."
125         dropsave
126         exit 0
127         ;;
128 1,"$head",*)
129         # Again the most common case of merging one remote.
130         echo "Updating from $head to $1."
131         git-update-index --refresh 2>/dev/null
132         new_head=$(git-rev-parse --verify "$1^0") &&
133         git-read-tree -u -m $head "$new_head" &&
134         finish "$new_head" "Fast forward"
135         dropsave
136         exit 0
137         ;;
138 1,?*"$LF"?*,*)
139         # We are not doing octopus and not fast forward.  Need a
140         # real merge.
141         ;;
142 1,*,)
143         # We are not doing octopus, not fast forward, and have only
144         # one common.  See if it is really trivial.
145         git var GIT_COMMITTER_IDENT >/dev/null || exit
146
147         echo "Trying really trivial in-index merge..."
148         git-update-index --refresh 2>/dev/null
149         if git-read-tree --trivial -m -u $common $head "$1" &&
150            result_tree=$(git-write-tree)
151         then
152             echo "Wonderful."
153             result_commit=$(
154                 echo "$merge_msg" |
155                 git-commit-tree $result_tree -p HEAD -p "$1"
156             ) || exit
157             finish "$result_commit" "In-index merge"
158             dropsave
159             exit 0
160         fi
161         echo "Nope."
162         ;;
163 *)
164         # An octopus.  If we can reach all the remote we are up to date.
165         up_to_date=t
166         for remote
167         do
168                 common_one=$(git-merge-base --all $head $remote)
169                 if test "$common_one" != "$remote"
170                 then
171                         up_to_date=f
172                         break
173                 fi
174         done
175         if test "$up_to_date" = t
176         then
177                 echo "Already up-to-date. Yeeah!"
178                 dropsave
179                 exit 0
180         fi
181         ;;
182 esac
183
184 # We are going to make a new commit.
185 git var GIT_COMMITTER_IDENT >/dev/null || exit
186
187 case "$use_strategies" in
188 '')
189         case "$#" in
190         1)
191                 use_strategies="$default_strategies" ;;
192         *)
193                 use_strategies=octopus ;;
194         esac            
195         ;;
196 esac
197
198 # At this point, we need a real merge.  No matter what strategy
199 # we use, it would operate on the index, possibly affecting the
200 # working tree, and when resolved cleanly, have the desired tree
201 # in the index -- this means that the index must be in sync with
202 # the $head commit.  The strategies are responsible to ensure this.
203
204 case "$use_strategies" in
205 ?*' '?*)
206     # Stash away the local changes so that we can try more than one.
207     savestate
208     single_strategy=no
209     ;;
210 *)
211     rm -f "$GIT_DIR/MERGE_SAVE"
212     single_strategy=yes
213     ;;
214 esac
215
216 result_tree= best_cnt=-1 best_strategy= wt_strategy=
217 merge_was_ok=
218 for strategy in $use_strategies
219 do
220     test "$wt_strategy" = '' || {
221         echo "Rewinding the tree to pristine..."
222         restorestate
223     }
224     case "$single_strategy" in
225     no)
226         echo "Trying merge strategy $strategy..."
227         ;;
228     esac
229
230     # Remember which strategy left the state in the working tree
231     wt_strategy=$strategy
232
233     git-merge-$strategy $common -- "$head_arg" "$@"
234     exit=$?
235     if test "$no_commit" = t && test "$exit" = 0
236     then
237         merge_was_ok=t
238         exit=1 ;# pretend it left conflicts.
239     fi
240
241     test "$exit" = 0 || {
242
243         # The backend exits with 1 when conflicts are left to be resolved,
244         # with 2 when it does not handle the given merge at all.
245
246         if test "$exit" -eq 1
247         then
248             cnt=`{
249                 git-diff-files --name-only
250                 git-ls-files --unmerged
251             } | wc -l`
252             if test $best_cnt -le 0 -o $cnt -le $best_cnt
253             then
254                 best_strategy=$strategy
255                 best_cnt=$cnt
256             fi
257         fi
258         continue
259     }
260
261     # Automerge succeeded.
262     result_tree=$(git-write-tree) && break
263 done
264
265 # If we have a resulting tree, that means the strategy module
266 # auto resolved the merge cleanly.
267 if test '' != "$result_tree"
268 then
269     parents="-p $head"
270     for remote
271     do
272         parents="$parents -p $remote"
273     done
274     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
275     finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
276     dropsave
277     exit 0
278 fi
279
280 # Pick the result from the best strategy and have the user fix it up.
281 case "$best_strategy" in
282 '')
283         restorestate
284         echo >&2 "No merge strategy handled the merge."
285         exit 2
286         ;;
287 "$wt_strategy")
288         # We already have its result in the working tree.
289         ;;
290 *)
291         echo "Rewinding the tree to pristine..."
292         restorestate
293         echo "Using the $best_strategy to prepare resolving by hand."
294         git-merge-$best_strategy $common -- "$head_arg" "$@"
295         ;;
296 esac
297 for remote
298 do
299         echo $remote
300 done >"$GIT_DIR/MERGE_HEAD"
301 echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
302
303 if test "$merge_was_ok" = t
304 then
305         echo >&2 \
306         "Automatic merge went well; stopped before committing as requested"
307         exit 0
308 else
309         {
310             echo '
311 Conflicts:
312 '
313                 git ls-files --unmerged |
314                 sed -e 's/^[^   ]*      /       /' |
315                 uniq
316         } >>"$GIT_DIR/MERGE_MSG"
317         if test -d "$GIT_DIR/rr-cache"
318         then
319                 git-rerere
320         fi
321         die "Automatic merge failed; fix up by hand"
322 fi