git/git-pull.sh
Junio C Hamano 7d0c68871a git-merge --squash
Some people tend to do many little commits on a topic branch,
recording all the trials and errors, and when the topic is
reasonably cooked well, would want to record the net effect of
the series as one commit on top of the mainline, removing the
cruft from the history.  The topic is then abandoned or forked
off again from that point at the mainline.

The barebone porcelainish that comes with core git tools does
not officially support such operation, but you can fake it by
using "git pull --no-merge" when such a topic branch is not a
strict superset of the mainline, like this:

	git checkout mainline
	git pull --no-commit . that-topic-branch
	: fix conflicts if any
	rm -f .git/MERGE_HEAD
        git commit -a -m 'consolidated commit log message'
	git branch -f that-topic-branch ;# now fully merged

This however does not work when the topic branch is a fast
forward of the mainline, because normal "git pull" will never
create a merge commit in such a case, and there is nothing
special --no-commit could do to begin with.

This patch introduces a new option, --squash, to support such a
workflow officially in both fast-forward case and true merge
case.  The user-level operation would be the same in both cases:

	git checkout mainline
        git pull --squash . that-topic-branch
        : fix conflicts if any -- naturally, there would be
        : no conflict if fast forward.
	git commit -a -m  'consolidated commit log message'
	git branch -f that-topic-branch ;# now fully merged

When the current branch is already up-to-date with respect to
the other branch, there truly is nothing to do, so the new
option does not have any effect.

This was brought up in #git IRC channel recently.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-24 01:11:19 -07:00

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#!/bin/sh
#
# Copyright (c) 2005 Junio C Hamano
#
# Fetch one or more remote refs and merge it/them into the current HEAD.
USAGE='[-n | --no-summary] [--no-commit] [-s strategy]... [<fetch-options>] <repo> <head>...'
LONG_USAGE='Fetch one or more remote refs and merge it/them into the current HEAD.'
. git-sh-setup
strategy_args= no_summary= no_commit= squash=
while case "$#,$1" in 0) break ;; *,-*) ;; *) break ;; esac
do
case "$1" in
-n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
--no-summa|--no-summar|--no-summary)
no_summary=-n ;;
--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
no_commit=--no-commit ;;
--sq|--squ|--squa|--squas|--squash)
squash=--squash ;;
-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
--strateg=*|--strategy=*|\
-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
case "$#,$1" in
*,*=*)
strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
1,*)
usage ;;
*)
strategy="$2"
shift ;;
esac
strategy_args="${strategy_args}-s $strategy "
;;
-h|--h|--he|--hel|--help)
usage
;;
-*)
# Pass thru anything that is meant for fetch.
break
;;
esac
shift
done
orig_head=$(git-rev-parse --verify HEAD) || die "Pulling into a black hole?"
git-fetch --update-head-ok "$@" || exit 1
curr_head=$(git-rev-parse --verify HEAD)
if test "$curr_head" != "$orig_head"
then
# The fetch involved updating the current branch.
# The working tree and the index file is still based on the
# $orig_head commit, but we are merging into $curr_head.
# First update the working tree to match $curr_head.
echo >&2 "Warning: fetch updated the current branch head."
echo >&2 "Warning: fast forwarding your working tree from"
echo >&2 "Warning: $orig_head commit."
git-update-index --refresh 2>/dev/null
git-read-tree -u -m "$orig_head" "$curr_head" ||
die 'Cannot fast-forward your working tree.
After making sure that you saved anything precious from
$ git diff '$orig_head'
output, run
$ git reset --hard
to recover.'
fi
merge_head=$(sed -e '/ not-for-merge /d' \
-e 's/ .*//' "$GIT_DIR"/FETCH_HEAD | \
tr '\012' ' ')
case "$merge_head" in
'')
echo >&2 "No changes."
exit 0
;;
?*' '?*)
var=`git-repo-config --get pull.octopus`
if test -n "$var"
then
strategy_default_args="-s $var"
fi
;;
*)
var=`git-repo-config --get pull.twohead`
if test -n "$var"
then
strategy_default_args="-s $var"
fi
;;
esac
case "$strategy_args" in
'')
strategy_args=$strategy_default_args
;;
esac
merge_name=$(git-fmt-merge-msg <"$GIT_DIR/FETCH_HEAD") || exit
git-merge $no_summary $no_commit $squash $strategy_args \
"$merge_name" HEAD $merge_head