git-commit-vandalism/git-pull.sh
Björn Gustavsson 134748353b Teach 'git merge' and 'git pull' the option --ff-only
For convenience in scripts and aliases, add the option
--ff-only to only allow fast-forwards (and up-to-date,
despite the name).

Disallow combining --ff-only and --no-ff, since they
flatly contradict each other.

Allow all other options to be combined with --ff-only
(i.e. do not add any code to handle them specially),
including the following options:

* --strategy (one or more): As long as the chosen merge
  strategy results in up-to-date or fast-forward, the
  command will succeed.

* --squash: I cannot imagine why anyone would want to
  squash commits only if fast-forward is possible, but I
  also see no reason why it should not be allowed.

* --message: The message will always be ignored, but I see
  no need to explicitly disallow providing a redundant message.

Acknowledgements: I did look at Yuval Kogman's earlier
patch (107768 in gmane), mainly as shortcut to find my
way in the code, but I did not copy anything directly.

Signed-off-by: Björn Gustavsson <bgustavsson@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-10-30 16:02:26 -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-stat] [--[no-]commit] [--[no-]squash] [--[no-]ff] [-s strategy]... [<fetch-options>] <repo> <head>...'
LONG_USAGE='Fetch one or more remote refs and merge it/them into the current HEAD.'
SUBDIRECTORY_OK=Yes
OPTIONS_SPEC=
. git-sh-setup
set_reflog_action "pull $*"
require_work_tree
cd_to_toplevel
test -z "$(git ls-files -u)" ||
die "You are in the middle of a conflicted merge."
strategy_args= diffstat= no_commit= squash= no_ff= ff_only=
log_arg= verbosity=
curr_branch=$(git symbolic-ref -q HEAD)
curr_branch_short=$(echo "$curr_branch" | sed "s|refs/heads/||")
rebase=$(git config --bool branch.$curr_branch_short.rebase)
while :
do
case "$1" in
-q|--quiet)
verbosity="$verbosity -q" ;;
-v|--verbose)
verbosity="$verbosity -v" ;;
-n|--no-stat|--no-summary)
diffstat=--no-stat ;;
--stat|--summary)
diffstat=--stat ;;
--log|--no-log)
log_arg=$1 ;;
--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
no_commit=--no-commit ;;
--c|--co|--com|--comm|--commi|--commit)
no_commit=--commit ;;
--sq|--squ|--squa|--squas|--squash)
squash=--squash ;;
--no-sq|--no-squ|--no-squa|--no-squas|--no-squash)
squash=--no-squash ;;
--ff)
no_ff=--ff ;;
--no-ff)
no_ff=--no-ff ;;
--ff-only)
ff_only=--ff-only ;;
-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
--strateg=*|--strategy=*|\
-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
case "$#,$1" in
*,*=*)
strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
1,*)
usage ;;
*)
strategy="$2"
shift ;;
esac
strategy_args="${strategy_args}-s $strategy "
;;
-r|--r|--re|--reb|--reba|--rebas|--rebase)
rebase=true
;;
--no-r|--no-re|--no-reb|--no-reba|--no-rebas|--no-rebase)
rebase=false
;;
-h|--h|--he|--hel|--help)
usage
;;
*)
# Pass thru anything that may be meant for fetch.
break
;;
esac
shift
done
error_on_no_merge_candidates () {
exec >&2
for opt
do
case "$opt" in
-t|--t|--ta|--tag|--tags)
echo "Fetching tags only, you probably meant:"
echo " git fetch --tags"
exit 1
esac
done
curr_branch=${curr_branch#refs/heads/}
upstream=$(git config "branch.$curr_branch.merge")
remote=$(git config "branch.$curr_branch.remote")
if [ $# -gt 1 ]; then
echo "There are no candidates for merging in the refs that you just fetched."
echo "Generally this means that you provided a wildcard refspec which had no"
echo "matches on the remote end."
elif [ $# -gt 0 ] && [ "$1" != "$remote" ]; then
echo "You asked to pull from the remote '$1', but did not specify"
echo "a branch to merge. Because this is not the default configured remote"
echo "for your current branch, you must specify a branch on the command line."
elif [ -z "$curr_branch" ]; then
echo "You are not currently on a branch, so I cannot use any"
echo "'branch.<branchname>.merge' in your configuration file."
echo "Please specify which branch you want to merge on the command"
echo "line and try again (e.g. 'git pull <repository> <refspec>')."
echo "See git-pull(1) for details."
elif [ -z "$upstream" ]; then
echo "You asked me to pull without telling me which branch you"
echo "want to merge with, and 'branch.${curr_branch}.merge' in"
echo "your configuration file does not tell me either. Please"
echo "specify which branch you want to merge on the command line and"
echo "try again (e.g. 'git pull <repository> <refspec>')."
echo "See git-pull(1) for details."
echo
echo "If you often merge with the same branch, you may want to"
echo "configure the following variables in your configuration"
echo "file:"
echo
echo " branch.${curr_branch}.remote = <nickname>"
echo " branch.${curr_branch}.merge = <remote-ref>"
echo " remote.<nickname>.url = <url>"
echo " remote.<nickname>.fetch = <refspec>"
echo
echo "See git-config(1) for details."
else
echo "Your configuration specifies to merge the ref '${upstream#refs/heads/}' from the"
echo "remote, but no such ref was fetched."
fi
exit 1
}
test true = "$rebase" && {
if ! git rev-parse -q --verify HEAD >/dev/null
then
# On an unborn branch
if test -f "$GIT_DIR/index"
then
die "updating an unborn branch with changes added to the index"
fi
else
git update-index --ignore-submodules --refresh &&
git diff-files --ignore-submodules --quiet &&
git diff-index --ignore-submodules --cached --quiet HEAD -- ||
die "refusing to pull with rebase: your working tree is not up-to-date"
fi
oldremoteref= &&
. git-parse-remote &&
remoteref="$(get_remote_merge_branch "$@" 2>/dev/null)" &&
oldremoteref="$(git rev-parse -q --verify "$remoteref")" &&
for reflog in $(git rev-list -g $remoteref 2>/dev/null)
do
if test "$reflog" = "$(git merge-base $reflog $curr_branch)"
then
oldremoteref="$reflog"
break
fi
done
}
orig_head=$(git rev-parse -q --verify HEAD)
git fetch $verbosity --update-head-ok "$@" || exit 1
curr_head=$(git rev-parse -q --verify HEAD)
if test -n "$orig_head" && 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: commit $orig_head."
git update-index -q --refresh
git read-tree -u -m "$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 "$merge_head" in
'')
error_on_no_merge_candidates "$@"
;;
?*' '?*)
if test -z "$orig_head"
then
die "Cannot merge multiple branches into empty head"
fi
if test true = "$rebase"
then
die "Cannot rebase onto multiple branches"
fi
;;
esac
if test -z "$orig_head"
then
git update-ref -m "initial pull" HEAD $merge_head "$curr_head" &&
git read-tree --reset -u HEAD || exit 1
exit
fi
merge_name=$(git fmt-merge-msg $log_arg <"$GIT_DIR/FETCH_HEAD") || exit
test true = "$rebase" &&
exec git-rebase $diffstat $strategy_args --onto $merge_head \
${oldremoteref:-$merge_head}
exec git-merge $diffstat $no_commit $squash $no_ff $ff_only $log_arg $strategy_args \
"$merge_name" HEAD $merge_head $verbosity