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 dropheads() {
  22         rm -f -- "$GIT_DIR/MERGE_HEAD" || exit 1
  23 }
  24
  25 summary() {
  26         case "$no_summary" in
  27         '')
  28                 git-diff-tree -p -M $head "$1" |
  29                 git-apply --stat --summary
  30                 ;;
  31         esac
  32 }
  33
  34 while case "$#" in 0) break ;; esac
  35 do
  36         case "$1" in
  37         -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
  38                 --no-summa|--no-summar|--no-summary)
  39                 no_summary=t ;;
  40         -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
  41                 --strateg=*|--strategy=*|\
  42         -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
  43                 case "$#,$1" in
  44                 *,*=*)
  45                         strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
  46                 1,*)
  47                         usage ;;
  48                 *)
  49                         strategy="$2"
  50                         shift ;;
  51                 esac
  52                 case " $all_strategies " in
  53                 *" $strategy "*)
  54                         use_strategies="$use_strategies$strategy " ;;
  55                 *)
  56                         die "available strategies are: $all_strategies" ;;
  57                 esac
  58                 ;;
  59         -*)     usage ;;
  60         *)      break ;;
  61         esac
  62         shift
  63 done
  64
  65 case "$use_strategies" in
  66 '')
  67         use_strategies=$default_strategies
  68         ;;
  69 esac
  70 test "$#" -le 2 && usage ;# we need at least two heads.
  71
  72 merge_msg="$1"
  73 shift
  74 head_arg="$1"
  75 head=$(git-rev-parse --verify "$1"^0) || usage
  76 shift
  77
  78 # All the rest are remote heads
  79 for remote
  80 do
  81         git-rev-parse --verify "$remote"^0 >/dev/null ||
  82             die "$remote - not something we can merge"
  83 done
  84
  85 common=$(git-show-branch --merge-base $head "$@")
  86 echo "$head" >"$GIT_DIR/ORIG_HEAD"
  87
  88 case "$#,$common" in
  89 *,'')
  90         die "Unable to find common commit between $head_arg and $*"
  91         ;;
  92 1,"$1")
  93         # If head can reach all the merge then we are up to date.
  94         # but first the most common case of merging one remote
  95         echo "Already up-to-date. Yeeah!"
  96         dropheads
  97         exit 0
  98         ;;
  99 1,"$head")
 100         # Again the most common case of merging one remote.
 101         echo "Updating from $head to $1."
 102         git-update-index --refresh 2>/dev/null
 103         git-read-tree -u -m $head "$1" || exit 1
 104         git-rev-parse --verify "$1^0" > "$GIT_DIR/HEAD"
 105         summary "$1"
 106         dropheads
 107         exit 0
 108         ;;
 109 1,*)
 110         # We are not doing octopus and not fast forward.  Need a
 111         # real merge.
 112         ;;
 113 *)
 114         # An octopus.  If we can reach all the remote we are up to date.
 115         up_to_date=t
 116         for remote
 117         do
 118                 common_one=$(git-merge-base $head $remote)
 119                 if test "$common_one" != "$remote"
 120                 then
 121                         up_to_date=f
 122                         break
 123                 fi
 124         done
 125         if test "$up_to_date" = t
 126         then
 127                 echo "Already up-to-date. Yeeah!"
 128                 dropheads
 129                 exit 0
 130         fi
 131         ;;
 132 esac
 133
 134 # At this point we need a real merge.  Require that the tree matches
 135 # exactly our head.
 136
 137 git-update-index --refresh &&
 138 test '' = "`git-diff-index --cached --name-only $head`" || {
 139         die "Need real merge but the working tree has local changes."
 140 }
 141
 142 result_tree= best_cnt=-1 best_strategy= wt_strategy=
 143 for strategy in $use_strategies
 144 do
 145     test "$wt_strategy" = '' || {
 146         echo "Rewinding the tree to pristine..."
 147         git reset --hard $head
 148     }
 149     echo "Trying merge strategy $strategy..."
 150     wt_strategy=$strategy
 151     git-merge-$strategy $common -- $head_arg "$@" || {
 152
 153         # The backend exits with 1 when conflicts are left to be resolved,
 154         # with 2 when it does not handle the given merge at all.
 155
 156         exit=$?
 157         if test "$exit" -eq 1
 158         then
 159             cnt=`{
 160                 git-diff-files --name-only
 161                 git-ls-files --unmerged
 162             } | wc -l`
 163             if test $best_cnt -le 0 -o $cnt -le $best_cnt
 164             then
 165                 best_strategy=$strategy
 166                 best_cnt=$cnt
 167             fi
 168         fi
 169         continue
 170     }
 171
 172     # Automerge succeeded.
 173     result_tree=$(git-write-tree) && break
 174 done
 175
 176 # If we have a resulting tree, that means the strategy module
 177 # auto resolved the merge cleanly.
 178 if test '' != "$result_tree"
 179 then
 180     parents="-p $head"
 181     for remote
 182     do
 183         parents="$parents -p $remote"
 184     done
 185     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents)
 186     echo "Committed merge $result_commit, made by $wt_strategy."
 187     echo $result_commit >"$GIT_DIR/HEAD"
 188     summary $result_commit
 189     dropheads
 190     exit 0
 191 fi
 192
 193 # Pick the result from the best strategy and have the user fix it up.
 194 case "$best_strategy" in
 195 '')
 196         git reset --hard $head
 197         die "No merge strategy handled the merge."
 198         ;;
 199 "$wt_strategy")
 200         # We already have its result in the working tree.
 201         ;;
 202 *)
 203         echo "Rewinding the tree to pristine..."
 204         git reset --hard $head
 205         echo "Using the $best_strategy to prepare resolving by hand."
 206         git-merge-$best_strategy $common -- $head_arg "$@"
 207         ;;
 208 esac
 209 for remote
 210 do
 211         echo $remote
 212 done >"$GIT_DIR/MERGE_HEAD"
 213 die "Automatic merge failed; fix up by hand"