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a005085240
This clarifies the logic to omit fast-forward check and omit trivial merge before running the specified strategy. The "index_merge" variable started out as a flag to say "do not do anything clever", but when recursive was changed to skip the trivial merge, the semantics were changed and the variable alone does not make sense anymore. This splits the variable into two, allow_fast_forward (which is almost always true, and avoids making a merge commit when the other commit is a descendant of our branch, but is set to false for ours and subtree) and allow_trivial_merge (which is false for ours, recursive and subtree). Unlike the earlier implementation, the "ours" strategy allows an up-to-date condition. When we are up-to-date, the result will be our commit, and by definition, we will have our tree as the result. Signed-off-by: Junio C Hamano <gitster@pobox.com>
506 lines
11 KiB
Bash
Executable file
506 lines
11 KiB
Bash
Executable file
#!/bin/sh
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#
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# Copyright (c) 2005 Junio C Hamano
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#
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USAGE='[-n] [--summary] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'
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SUBDIRECTORY_OK=Yes
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. git-sh-setup
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require_work_tree
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cd_to_toplevel
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test -z "$(git ls-files -u)" ||
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die "You are in the middle of a conflicted merge."
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LF='
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'
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all_strategies='recur recursive octopus resolve stupid ours subtree'
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default_twohead_strategies='recursive'
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default_octopus_strategies='octopus'
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no_fast_forward_strategies='subtree ours'
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no_trivial_strategies='recursive recur subtree ours'
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use_strategies=
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allow_fast_forward=t
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allow_trivial_merge=t
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dropsave() {
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rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
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"$GIT_DIR/MERGE_SAVE" || exit 1
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}
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savestate() {
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# Stash away any local modifications.
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git diff-index -z --name-only $head |
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cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
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}
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restorestate() {
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if test -f "$GIT_DIR/MERGE_SAVE"
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then
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git reset --hard $head >/dev/null
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cpio -iuv <"$GIT_DIR/MERGE_SAVE"
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git update-index --refresh >/dev/null
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fi
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}
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finish_up_to_date () {
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case "$squash" in
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t)
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echo "$1 (nothing to squash)" ;;
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'')
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echo "$1" ;;
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esac
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dropsave
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}
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squash_message () {
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echo Squashed commit of the following:
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echo
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git log --no-merges ^"$head" $remote
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}
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finish () {
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if test '' = "$2"
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then
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rlogm="$GIT_REFLOG_ACTION"
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else
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echo "$2"
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rlogm="$GIT_REFLOG_ACTION: $2"
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fi
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case "$squash" in
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t)
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echo "Squash commit -- not updating HEAD"
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squash_message >"$GIT_DIR/SQUASH_MSG"
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;;
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'')
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case "$merge_msg" in
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'')
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echo "No merge message -- not updating HEAD"
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;;
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*)
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git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
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;;
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esac
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;;
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esac
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case "$1" in
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'')
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;;
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?*)
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if test "$show_diffstat" = t
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then
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# We want color (if set), but no pager
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GIT_PAGER='' git diff --stat --summary -M "$head" "$1"
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fi
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;;
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esac
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}
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merge_name () {
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remote="$1"
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rh=$(git rev-parse --verify "$remote^0" 2>/dev/null) || return
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bh=$(git show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
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if test "$rh" = "$bh"
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then
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echo "$rh branch '$remote' of ."
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elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
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git show-ref -q --verify "refs/heads/$truname" 2>/dev/null
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then
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echo "$rh branch '$truname' (early part) of ."
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elif test "$remote" = "FETCH_HEAD" -a -r "$GIT_DIR/FETCH_HEAD"
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then
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sed -e 's/ not-for-merge / /' -e 1q \
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"$GIT_DIR/FETCH_HEAD"
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else
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echo "$rh commit '$remote'"
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fi
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}
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case "$#" in 0) usage ;; esac
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have_message=
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while case "$#" in 0) break ;; esac
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do
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case "$1" in
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-n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
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--no-summa|--no-summar|--no-summary)
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show_diffstat=false ;;
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--summary)
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show_diffstat=t ;;
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--sq|--squ|--squa|--squas|--squash)
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squash=t no_commit=t ;;
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--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
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no_commit=t ;;
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-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
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--strateg=*|--strategy=*|\
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-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
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case "$#,$1" in
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*,*=*)
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strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
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1,*)
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usage ;;
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*)
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strategy="$2"
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shift ;;
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esac
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case " $all_strategies " in
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*" $strategy "*)
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use_strategies="$use_strategies$strategy " ;;
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*)
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die "available strategies are: $all_strategies" ;;
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esac
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;;
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-m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
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merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
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have_message=t
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;;
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-m|--m|--me|--mes|--mess|--messa|--messag|--message)
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shift
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case "$#" in
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1) usage ;;
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esac
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merge_msg="$1"
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have_message=t
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;;
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-*) usage ;;
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*) break ;;
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esac
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shift
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done
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if test -z "$show_diffstat"; then
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test "$(git config --bool merge.diffstat)" = false && show_diffstat=false
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test -z "$show_diffstat" && show_diffstat=t
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fi
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# This could be traditional "merge <msg> HEAD <commit>..." and the
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# way we can tell it is to see if the second token is HEAD, but some
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# people might have misused the interface and used a committish that
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# is the same as HEAD there instead. Traditional format never would
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# have "-m" so it is an additional safety measure to check for it.
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if test -z "$have_message" &&
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second_token=$(git rev-parse --verify "$2^0" 2>/dev/null) &&
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head_commit=$(git rev-parse --verify "HEAD" 2>/dev/null) &&
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test "$second_token" = "$head_commit"
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then
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merge_msg="$1"
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shift
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head_arg="$1"
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shift
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elif ! git rev-parse --verify HEAD >/dev/null 2>&1
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then
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# If the merged head is a valid one there is no reason to
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# forbid "git merge" into a branch yet to be born. We do
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# the same for "git pull".
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if test 1 -ne $#
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then
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echo >&2 "Can merge only exactly one commit into empty head"
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exit 1
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fi
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rh=$(git rev-parse --verify "$1^0") ||
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die "$1 - not something we can merge"
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git update-ref -m "initial pull" HEAD "$rh" "" &&
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git read-tree --reset -u HEAD
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exit
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else
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# We are invoked directly as the first-class UI.
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head_arg=HEAD
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# All the rest are the commits being merged; prepare
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# the standard merge summary message to be appended to
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# the given message. If remote is invalid we will die
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# later in the common codepath so we discard the error
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# in this loop.
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merge_name=$(for remote
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do
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merge_name "$remote"
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done | git fmt-merge-msg
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)
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merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
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fi
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head=$(git rev-parse --verify "$head_arg"^0) || usage
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# All the rest are remote heads
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test "$#" = 0 && usage ;# we need at least one remote head.
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set_reflog_action "merge $*"
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remoteheads=
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for remote
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do
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remotehead=$(git rev-parse --verify "$remote"^0 2>/dev/null) ||
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die "$remote - not something we can merge"
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remoteheads="${remoteheads}$remotehead "
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eval GITHEAD_$remotehead='"$remote"'
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export GITHEAD_$remotehead
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done
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set x $remoteheads ; shift
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case "$use_strategies" in
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'')
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case "$#" in
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1)
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var="`git config --get pull.twohead`"
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if test -n "$var"
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then
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use_strategies="$var"
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else
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use_strategies="$default_twohead_strategies"
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fi ;;
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*)
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var="`git config --get pull.octopus`"
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if test -n "$var"
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then
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use_strategies="$var"
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else
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use_strategies="$default_octopus_strategies"
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fi ;;
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esac
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;;
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esac
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for s in $use_strategies
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do
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for ss in $no_fast_forward_strategies
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do
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case " $s " in
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*" $ss "*)
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allow_fast_forward=f
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break
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;;
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esac
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done
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for ss in $no_trivial_strategies
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do
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case " $s " in
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*" $ss "*)
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allow_trivial_merge=f
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break
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;;
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esac
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done
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done
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case "$#" in
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1)
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common=$(git merge-base --all $head "$@")
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;;
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*)
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common=$(git show-branch --merge-base $head "$@")
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;;
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esac
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echo "$head" >"$GIT_DIR/ORIG_HEAD"
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case "$allow_fast_forward,$#,$common,$no_commit" in
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?,*,'',*)
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# No common ancestors found. We need a real merge.
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;;
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?,1,"$1",*)
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# If head can reach all the merge then we are up to date.
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# but first the most common case of merging one remote.
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finish_up_to_date "Already up-to-date."
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exit 0
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;;
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t,1,"$head",*)
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# Again the most common case of merging one remote.
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echo "Updating $(git rev-parse --short $head)..$(git rev-parse --short $1)"
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git update-index --refresh 2>/dev/null
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msg="Fast forward"
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if test -n "$have_message"
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then
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msg="$msg (no commit created; -m option ignored)"
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fi
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new_head=$(git rev-parse --verify "$1^0") &&
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git read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
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finish "$new_head" "$msg" || exit
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dropsave
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exit 0
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;;
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?,1,?*"$LF"?*,*)
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# We are not doing octopus and not fast forward. Need a
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# real merge.
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;;
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?,1,*,)
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# We are not doing octopus, not fast forward, and have only
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# one common.
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git update-index --refresh 2>/dev/null
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case "$allow_trivial_merge" in
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t)
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# See if it is really trivial.
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git var GIT_COMMITTER_IDENT >/dev/null || exit
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echo "Trying really trivial in-index merge..."
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if git read-tree --trivial -m -u -v $common $head "$1" &&
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result_tree=$(git write-tree)
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then
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echo "Wonderful."
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result_commit=$(
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printf '%s\n' "$merge_msg" |
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git commit-tree $result_tree -p HEAD -p "$1"
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) || exit
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finish "$result_commit" "In-index merge"
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dropsave
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exit 0
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fi
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echo "Nope."
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esac
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;;
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*)
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# An octopus. If we can reach all the remote we are up to date.
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up_to_date=t
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for remote
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do
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common_one=$(git merge-base --all $head $remote)
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if test "$common_one" != "$remote"
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then
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up_to_date=f
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break
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fi
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done
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if test "$up_to_date" = t
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then
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finish_up_to_date "Already up-to-date. Yeeah!"
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exit 0
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fi
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;;
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esac
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# We are going to make a new commit.
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git var GIT_COMMITTER_IDENT >/dev/null || exit
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# At this point, we need a real merge. No matter what strategy
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# we use, it would operate on the index, possibly affecting the
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# working tree, and when resolved cleanly, have the desired tree
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# in the index -- this means that the index must be in sync with
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# the $head commit. The strategies are responsible to ensure this.
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case "$use_strategies" in
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?*' '?*)
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# Stash away the local changes so that we can try more than one.
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savestate
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single_strategy=no
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;;
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*)
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rm -f "$GIT_DIR/MERGE_SAVE"
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single_strategy=yes
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;;
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esac
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result_tree= best_cnt=-1 best_strategy= wt_strategy=
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merge_was_ok=
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for strategy in $use_strategies
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do
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test "$wt_strategy" = '' || {
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echo "Rewinding the tree to pristine..."
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restorestate
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}
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case "$single_strategy" in
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no)
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echo "Trying merge strategy $strategy..."
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;;
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esac
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# Remember which strategy left the state in the working tree
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wt_strategy=$strategy
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git-merge-$strategy $common -- "$head_arg" "$@"
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exit=$?
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if test "$no_commit" = t && test "$exit" = 0
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then
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merge_was_ok=t
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exit=1 ;# pretend it left conflicts.
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fi
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test "$exit" = 0 || {
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# The backend exits with 1 when conflicts are left to be resolved,
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# with 2 when it does not handle the given merge at all.
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if test "$exit" -eq 1
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then
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cnt=`{
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git diff-files --name-only
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git ls-files --unmerged
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} | wc -l`
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if test $best_cnt -le 0 -o $cnt -le $best_cnt
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then
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best_strategy=$strategy
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best_cnt=$cnt
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fi
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fi
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continue
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}
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# Automerge succeeded.
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result_tree=$(git write-tree) && break
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done
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# If we have a resulting tree, that means the strategy module
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# auto resolved the merge cleanly.
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if test '' != "$result_tree"
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then
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parents=$(git show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
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result_commit=$(printf '%s\n' "$merge_msg" | git commit-tree $result_tree $parents) || exit
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finish "$result_commit" "Merge made by $wt_strategy."
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dropsave
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exit 0
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fi
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# Pick the result from the best strategy and have the user fix it up.
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case "$best_strategy" in
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'')
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restorestate
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case "$use_strategies" in
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?*' '?*)
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echo >&2 "No merge strategy handled the merge."
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;;
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*)
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echo >&2 "Merge with strategy $use_strategies failed."
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;;
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esac
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exit 2
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;;
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"$wt_strategy")
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# We already have its result in the working tree.
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;;
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*)
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echo "Rewinding the tree to pristine..."
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restorestate
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echo "Using the $best_strategy to prepare resolving by hand."
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git-merge-$best_strategy $common -- "$head_arg" "$@"
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;;
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esac
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if test "$squash" = t
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then
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finish
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else
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for remote
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do
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echo $remote
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done >"$GIT_DIR/MERGE_HEAD"
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printf '%s\n' "$merge_msg" >"$GIT_DIR/MERGE_MSG"
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fi
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if test "$merge_was_ok" = t
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then
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echo >&2 \
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"Automatic merge went well; stopped before committing as requested"
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exit 0
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else
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{
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echo '
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Conflicts:
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'
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git ls-files --unmerged |
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sed -e 's/^[^ ]* / /' |
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uniq
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} >>"$GIT_DIR/MERGE_MSG"
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git rerere
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die "Automatic merge failed; fix conflicts and then commit the result."
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fi
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