git-merge.sh

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