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cf65426de6
Prior toc85c792(pull --rebase: be cleverer with rebased upstream branches, 2008-01-26), pull --rebase would run git rebase $merge_head which resulted in a call to git format-patch ... --ignore-if-in-upstream $merge_head..$cur_branch This resulted in patches from $merge_head..$cur_branch being applied, as long as they did not already exist in $cur_branch..$merge_head. Unfortunately, when upstream is rebased, $merge_head..$cur_branch also refers to "old" commits that have already been rebased upstream, meaning that many patches that were already fixed upstream would be reapplied. This could result in many spurious conflicts, as well as reintroduce patches that were intentionally dropped upstream. So the algorithm was changed inc85c792(pull --rebase: be cleverer with rebased upstream branches, 2008-01-26) andd44e712(pull: support rebased upstream + fetch + pull --rebase, 2009-07-19). Defining $old_remote_ref to be the most recent entry in the reflog for @{upstream} that is an ancestor of $cur_branch, pull --rebase was changed to run git rebase --onto $merge_head $old_remote_ref which results in a call to git format-patch ... --ignore-if-in-upstream $old_remote_ref..$cur_branch The whole point of this change was to reduce the number of commits being reapplied, by avoiding commits that upstream already has or had. In the rebased upstream case, this change achieved that purpose. It is worth noting, though, that since $old_remote_ref is always an ancestor of $cur_branch (by its definition), format-patch will not know what upstream is and thus will not be able to determine if any patches are already upstream; they will all be reapplied. In the non-rebased upstream case, this new form is usually the same as the original code but in some cases $old_remote_ref can be an ancestor of $(git merge-base $merge_head $cur_branch) meaning that instead of avoiding reapplying commits that upstream already has, it actually includes more such commits. Combined with the fact that format-patch can no longer detect commits that are already upstream (since it is no longer told what upstream is), results in lots of confusion for users (e.g. "git is giving me lots of conflicts in stuff I didn't even change since my last push.") Cases where additional commits could be reapplied include forking from a commit other than the tracking branch, or amending/rebasing after pushing. Cases where the inability to detect upstreamed commits cause problems include independent discovery of a fix and having your patches get upstreamed by some alternative route (e.g. pulling your changes to a third machine, pushing from there, and then going back to your original machine and trying to pull --rebase). Fix the non-rebased upstream case by ignoring $old_remote_ref whenever it is contained in $(git merge-base $merge_head $cur_branch). This should have no affect on the rebased upstream case. Acked-by: Santi Béjar <santi@agolina.net> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
291 lines
8 KiB
Bash
Executable file
291 lines
8 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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# Fetch one or more remote refs and merge it/them into the current HEAD.
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USAGE='[-n | --no-stat] [--[no-]commit] [--[no-]squash] [--[no-]ff] [-s strategy]... [<fetch-options>] <repo> <head>...'
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LONG_USAGE='Fetch one or more remote refs and merge it/them into the current HEAD.'
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SUBDIRECTORY_OK=Yes
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OPTIONS_SPEC=
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. git-sh-setup
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set_reflog_action "pull $*"
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require_work_tree
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cd_to_toplevel
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die_conflict () {
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git diff-index --cached --name-status -r --ignore-submodules HEAD --
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if [ $(git config --bool --get advice.resolveConflict || echo true) = "true" ]; then
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die "Pull is not possible because you have unmerged files.
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Please, fix them up in the work tree, and then use 'git add/rm <file>'
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as appropriate to mark resolution, or use 'git commit -a'."
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else
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die "Pull is not possible because you have unmerged files."
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fi
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}
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die_merge () {
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if [ $(git config --bool --get advice.resolveConflict || echo true) = "true" ]; then
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die "You have not concluded your merge (MERGE_HEAD exists).
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Please, commit your changes before you can merge."
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else
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die "You have not concluded your merge (MERGE_HEAD exists)."
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fi
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}
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test -z "$(git ls-files -u)" || die_conflict
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test -f "$GIT_DIR/MERGE_HEAD" && die_merge
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strategy_args= diffstat= no_commit= squash= no_ff= ff_only=
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log_arg= verbosity=
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merge_args=
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curr_branch=$(git symbolic-ref -q HEAD)
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curr_branch_short=$(echo "$curr_branch" | sed "s|refs/heads/||")
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rebase=$(git config --bool branch.$curr_branch_short.rebase)
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while :
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do
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case "$1" in
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-q|--quiet)
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verbosity="$verbosity -q" ;;
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-v|--verbose)
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verbosity="$verbosity -v" ;;
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-n|--no-stat|--no-summary)
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diffstat=--no-stat ;;
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--stat|--summary)
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diffstat=--stat ;;
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--log|--no-log)
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log_arg=$1 ;;
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--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
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no_commit=--no-commit ;;
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--c|--co|--com|--comm|--commi|--commit)
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no_commit=--commit ;;
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--sq|--squ|--squa|--squas|--squash)
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squash=--squash ;;
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--no-sq|--no-squ|--no-squa|--no-squas|--no-squash)
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squash=--no-squash ;;
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--ff)
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no_ff=--ff ;;
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--no-ff)
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no_ff=--no-ff ;;
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--ff-only)
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ff_only=--ff-only ;;
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-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
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--strateg=*|--strategy=*|\
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-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
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case "$#,$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="$2"
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shift ;;
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esac
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strategy_args="${strategy_args}-s $strategy "
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;;
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-X*)
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case "$#,$1" in
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1,-X)
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usage ;;
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*,-X)
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xx="-X $(git rev-parse --sq-quote "$2")"
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shift ;;
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*,*)
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xx=$(git rev-parse --sq-quote "$1") ;;
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esac
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merge_args="$merge_args$xx "
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;;
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-r|--r|--re|--reb|--reba|--rebas|--rebase)
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rebase=true
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;;
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--no-r|--no-re|--no-reb|--no-reba|--no-rebas|--no-rebase)
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rebase=false
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;;
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-h|--h|--he|--hel|--help)
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usage
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;;
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*)
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# Pass thru anything that may be meant for fetch.
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break
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;;
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esac
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shift
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done
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error_on_no_merge_candidates () {
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exec >&2
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for opt
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do
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case "$opt" in
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-t|--t|--ta|--tag|--tags)
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echo "Fetching tags only, you probably meant:"
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echo " git fetch --tags"
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exit 1
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esac
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done
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if test true = "$rebase"
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then
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op_type=rebase
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op_prep=against
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else
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op_type=merge
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op_prep=with
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fi
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curr_branch=${curr_branch#refs/heads/}
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upstream=$(git config "branch.$curr_branch.merge")
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remote=$(git config "branch.$curr_branch.remote")
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if [ $# -gt 1 ]; then
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if [ "$rebase" = true ]; then
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printf "There is no candidate for rebasing against "
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else
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printf "There are no candidates for merging "
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fi
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echo "among the refs that you just fetched."
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echo "Generally this means that you provided a wildcard refspec which had no"
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echo "matches on the remote end."
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elif [ $# -gt 0 ] && [ "$1" != "$remote" ]; then
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echo "You asked to pull from the remote '$1', but did not specify"
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echo "a branch. Because this is not the default configured remote"
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echo "for your current branch, you must specify a branch on the command line."
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elif [ -z "$curr_branch" ]; then
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echo "You are not currently on a branch, so I cannot use any"
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echo "'branch.<branchname>.merge' in your configuration file."
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echo "Please specify which remote branch you want to use on the command"
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echo "line and try again (e.g. 'git pull <repository> <refspec>')."
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echo "See git-pull(1) for details."
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elif [ -z "$upstream" ]; then
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echo "You asked me to pull without telling me which branch you"
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echo "want to $op_type $op_prep, and 'branch.${curr_branch}.merge' in"
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echo "your configuration file does not tell me, either. Please"
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echo "specify which branch you want to use on the command line and"
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echo "try again (e.g. 'git pull <repository> <refspec>')."
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echo "See git-pull(1) for details."
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echo
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echo "If you often $op_type $op_prep the same branch, you may want to"
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echo "use something like the following in your configuration file:"
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echo
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echo " [branch \"${curr_branch}\"]"
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echo " remote = <nickname>"
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echo " merge = <remote-ref>"
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test rebase = "$op_type" &&
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echo " rebase = true"
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echo
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echo " [remote \"<nickname>\"]"
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echo " url = <url>"
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echo " fetch = <refspec>"
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echo
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echo "See git-config(1) for details."
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else
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echo "Your configuration specifies to $op_type $op_prep the ref '${upstream#refs/heads/}'"
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echo "from the remote, but no such ref was fetched."
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fi
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exit 1
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}
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test true = "$rebase" && {
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if ! git rev-parse -q --verify HEAD >/dev/null
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then
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# On an unborn branch
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if test -f "$GIT_DIR/index"
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then
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die "updating an unborn branch with changes added to the index"
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fi
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else
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git update-index --ignore-submodules --refresh &&
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git diff-files --ignore-submodules --quiet &&
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git diff-index --ignore-submodules --cached --quiet HEAD -- ||
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die "refusing to pull with rebase: your working tree is not up-to-date"
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fi
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oldremoteref= &&
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. git-parse-remote &&
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remoteref="$(get_remote_merge_branch "$@" 2>/dev/null)" &&
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oldremoteref="$(git rev-parse -q --verify "$remoteref")" &&
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for reflog in $(git rev-list -g $remoteref 2>/dev/null)
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do
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if test "$reflog" = "$(git merge-base $reflog $curr_branch)"
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then
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oldremoteref="$reflog"
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break
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fi
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done
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}
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orig_head=$(git rev-parse -q --verify HEAD)
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git fetch $verbosity --update-head-ok "$@" || exit 1
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curr_head=$(git rev-parse -q --verify HEAD)
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if test -n "$orig_head" && test "$curr_head" != "$orig_head"
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then
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# The fetch involved updating the current branch.
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# The working tree and the index file is still based on the
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# $orig_head commit, but we are merging into $curr_head.
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# First update the working tree to match $curr_head.
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echo >&2 "Warning: fetch updated the current branch head."
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echo >&2 "Warning: fast-forwarding your working tree from"
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echo >&2 "Warning: commit $orig_head."
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git update-index -q --refresh
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git read-tree -u -m "$orig_head" "$curr_head" ||
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die 'Cannot fast-forward your working tree.
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After making sure that you saved anything precious from
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$ git diff '$orig_head'
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output, run
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$ git reset --hard
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to recover.'
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fi
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merge_head=$(sed -e '/ not-for-merge /d' \
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-e 's/ .*//' "$GIT_DIR"/FETCH_HEAD | \
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tr '\012' ' ')
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case "$merge_head" in
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'')
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error_on_no_merge_candidates "$@"
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;;
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?*' '?*)
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if test -z "$orig_head"
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then
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die "Cannot merge multiple branches into empty head"
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fi
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if test true = "$rebase"
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then
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die "Cannot rebase onto multiple branches"
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fi
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;;
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esac
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if test -z "$orig_head"
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then
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git update-ref -m "initial pull" HEAD $merge_head "$curr_head" &&
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git read-tree --reset -u HEAD || exit 1
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exit
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fi
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if test true = "$rebase"
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then
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o=$(git show-branch --merge-base $curr_branch $merge_head $oldremoteref)
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if test "$oldremoteref" = "$o"
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then
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unset oldremoteref
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fi
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fi
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merge_name=$(git fmt-merge-msg $log_arg <"$GIT_DIR/FETCH_HEAD") || exit
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case "$rebase" in
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true)
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eval="git-rebase $diffstat $strategy_args $merge_args"
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eval="$eval --onto $merge_head ${oldremoteref:-$merge_head}"
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;;
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*)
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eval="git-merge $diffstat $no_commit $squash $no_ff $ff_only"
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eval="$eval $log_arg $strategy_args $merge_args"
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eval="$eval \"\$merge_name\" HEAD $merge_head $verbosity"
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;;
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esac
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eval "exec $eval"
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