如何为git rebase选择合并策略？

Question

git-rebase man page mentions -X<option> can be passed to git-merge . When/how exactly?

I'd like to rebase by applying patches with recursive strategy and theirs option (apply whatever sticks, rather than skipping entire conflicting commits). I don't want merge, I want to make history linear.

I've tried:

git rebase -Xtheirs

and

git rebase -s 'recursive -Xtheirs'

but git rejects -X in both cases.

---

git rebase -Xtheirs works in recent versions, except tree conflicts need to be resolved manually. You need to run git rebase -Xtheirs --continue (with -X repeated) after resolving those conflicts.

Answer 1

You can use this with Git v1.7.3 or later versions.

git rebase --strategy-option theirs ${branch} # Long option
git rebase -X theirs ${branch} # Short option

(which is a short for git rebase --strategy recursive --strategy-option theirs ${branch} as stated by the documentation )

From Git v1.7.3 Release Notes:

git rebase --strategy <s> learned the --strategy-option / -X option to pass extra options that are understood by the chosen merge strategy.

NB: "Ours" and "theirs" mean the opposite of what they do during a straight merge. In other words, "theirs" favors the commits on the current branch.

Answer 2

This is for merge strategies that come with their own set of options

git rebase <branch> -s recursive -X theirs

should work, although this patch mentions (February 2010):

The manpage says that git-rebase supports merge strategies, but the rebase command doesn't know about -X , and gives the usage when presented with it.

So if it still doesn't work, it is being debated right now!
(supported in recent git)

---

Update from commit db2b3b820e2b28da268cc88adff076b396392dfe (July 2013, git 1.8.4+),

Do not ignore merge options in interactive rebase

Merge strategy and its options can be specified in git rebase , but with -- interactive , they were completely ignored.

Signed-off-by: Arnaud Fontaine

That means -X and strategy now work with interactive rebase, as well as plain rebase.

Answer 3

As iCrazy said, this feature is only available for git 1.7.3 onwards. So, for the poor souls (like me) still using 1.7.1, I present a solution I did myself:

git-rebase-theirs

It is a very well-polished (and thus long) script, meant for production use: ui options, handles multiple files, check if file actually has conflict markers, etc, but the "core" could be summarized in 2 lines:

cp file file.bak
awk '/^<+ HEAD$/,/^=+$/{next} /^>+ /{next} 1' file.bak > file

And here is the full script:

#!/bin/bash
#
# git-rebase-theirs - Resolve rebase conflicts by favoring 'theirs' version
#
#    Copyright (C) 2012 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program. If not see <http://www.gnu.org/licenses/gpl.html>

#Defaults:
verbose=0
backup=1
inplace=0
ext=".bak"

message() { printf "%s\n" "$1" >&2 ; }
skip()    { message "skipping ${2:-$file}${1:+: $1}"; continue ; }
argerr()  { printf "%s: %s\n" "$myname" "${1:-error}" >&2 ; usage 1 ; }
invalid() { argerr "invalid option: $1" ; }
missing() { argerr "missing${1:+ $1} operand." ; }

usage() {
    cat <<- USAGE
    Usage: $myname [options] [--] FILE...
    USAGE
    if [[ "$1" ]] ; then
        cat >&2 <<- USAGE
        Try '$myname --help' for more information.
        USAGE
        exit 1
    fi
    cat <<-USAGE

    Resolve git rebase conflicts in FILE(s) by favoring 'theirs' version

    When using git rebase, conflicts are usually wanted to be resolved
    by favoring the <working branch> version (the branch being rebased,
    'theirs' side in a rebase), instead of the <upstream> version (the
    base branch, 'ours' side)

    But git rebase --strategy -X theirs is only available from git 1.7.3
    For older versions, $myname is the solution.

    It works by discarding all lines between '<<<<<<< HEAD' and '========'
    inclusive, and also the the '>>>>>> commit' marker.

    By default it outputs to stdout, but files can be edited in-place
    using --in-place, which, unlike sed, creates a backup by default.

    Options:
      -h|--help            show this page.
      -v|--verbose         print more details in stderr.

      --in-place[=SUFFIX]  edit files in place, creating a backup with
                           SUFFIX extension. Default if blank is ""$ext"

       --no-backup         disables backup

    Copyright (C) 2012 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
    License: GPLv3 or later. See <http://www.gnu.org/licenses/gpl.html>
    USAGE
    exit 0
}
myname="${0##*/}"

# Option handling
files=()
while (( $# )); do
    case "$1" in
    -h|--help     ) usage            ;;
    -v|--verbose  ) verbose=1        ;;
    --no-backup   ) backup=0         ;;
    --in-place    ) inplace=1        ;;
    --in-place=*  ) inplace=1
                    suffix="${1#*=}" ;;
    -*            ) invalid "$1"     ;;
    --            ) shift ; break    ;;
    *             ) files+=( "$1" )  ;;
    esac
    shift
done
files+=( "$@" )

(( "${#files[@]}" )) || missing "FILE"

ext=${suffix:-$ext}

for file in "${files[@]}"; do

    [[ -f "$file" ]] || skip "not a valid file"

    if ((inplace)); then
        outfile=$(tempfile) || skip "could not create temporary file"
        trap 'rm -f -- "$outfile"' EXIT
        cp "$file" "$outfile" || skip
        exec 3>"$outfile"
    else
        exec 3>&1
    fi

    # Do the magic :)
    awk '/^<+ HEAD$/,/^=+$/{next} /^>+ /{next} 1' "$file" >&3

    exec 3>&-

    ((inplace)) || continue

    diff "$file" "$outfile" >/dev/null && skip "no conflict markers found"

    ((backup)) && { cp "$file" "$file$ext" || skip "could not backup" ; }

    cp "$outfile" "$file" || skip "could not edit in-place"

    ((verbose)) && message "resolved ${file}"
done