Skip to main content

Browse the archive

Revision 20c3fe762105a29150fd21e3e0a340bca7890848 authored by Paul Tan on 06 June 2015, 11:46:10 UTC, committed by Junio C Hamano on 08 June 2015, 20:09:20 UTC 
am --abort: revert changes introduced by failed 3way merge
 
Even when a merge conflict occurs with am --3way, the index will be
modified with the results of any successfully merged files. These
changes to the index will not be reverted with a
"git read-tree --reset -u HEAD ORIG_HEAD", as git read-tree will not be
aware of how the current index differs from HEAD or ORIG_HEAD.

To fix this, we first reset any conflicting entries in the index. The
resulting index will contain the results of successfully merged files
introduced by the failed merge. We write this index to a tree, and then
use git read-tree to fast-forward this "index tree" back to ORIG_HEAD,
thus undoing all the changes from the failed merge.

When we are on an unborn branch, HEAD and ORIG_HEAD will not point to
valid trees. In this case, use an empty tree.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent f8da680
Raw File
lib-pack.sh 
# Support routines for hand-crafting weird or malicious packs.
#
# You can make a complete pack like:
#
#   pack_header 2 >foo.pack &&
#   pack_obj e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 >>foo.pack &&
#   pack_obj e68fe8129b546b101aee9510c5328e7f21ca1d18 >>foo.pack &&
#   pack_trailer foo.pack

# Print the big-endian 4-byte octal representation of $1
uint32_octal () {
	n=$1
	printf '\\%o' $(($n / 16777216)); n=$((n % 16777216))
	printf '\\%o' $(($n /    65536)); n=$((n %    65536))
	printf '\\%o' $(($n /      256)); n=$((n %      256))
	printf '\\%o' $(($n           ));
}

# Print the big-endian 4-byte binary representation of $1
uint32_binary () {
	printf "$(uint32_octal "$1")"
}

# Print a pack header, version 2, for a pack with $1 objects
pack_header () {
	printf 'PACK' &&
	printf '\0\0\0\2' &&
	uint32_binary "$1"
}

# Print the pack data for object $1, as a delta against object $2 (or as a full
# object if $2 is missing or empty). The output is suitable for including
# directly in the packfile, and represents the entirety of the object entry.
# Doing this on the fly (especially picking your deltas) is quite tricky, so we
# have hardcoded some well-known objects. See the case statements below for the
# complete list.
pack_obj () {
	case "$1" in
	# empty blob
	e69de29bb2d1d6434b8b29ae775ad8c2e48c5391)
		case "$2" in
		'')
			printf '\060\170\234\003\0\0\0\0\1'
			return
			;;
		esac
		;;

	# blob containing "\7\76"
	e68fe8129b546b101aee9510c5328e7f21ca1d18)
		case "$2" in
		'')
			printf '\062\170\234\143\267\3\0\0\116\0\106'
			return
			;;
		01d7713666f4de822776c7622c10f1b07de280dc)
			printf '\165\1\327\161\66\146\364\336\202\47\166' &&
			printf '\307\142\54\20\361\260\175\342\200\334\170' &&
			printf '\234\143\142\142\142\267\003\0\0\151\0\114'
			return
			;;
		esac
		;;

	# blob containing "\7\0"
	01d7713666f4de822776c7622c10f1b07de280dc)
		case "$2" in
		'')
			printf '\062\170\234\143\147\0\0\0\20\0\10'
			return
			;;
		e68fe8129b546b101aee9510c5328e7f21ca1d18)
			printf '\165\346\217\350\22\233\124\153\20\32\356' &&
			printf '\225\20\305\62\216\177\41\312\35\30\170\234' &&
			printf '\143\142\142\142\147\0\0\0\53\0\16'
			return
			;;
		esac
		;;
	esac

	echo >&2 "BUG: don't know how to print $1${2:+ (from $2)}"
	return 1
}

# Compute and append pack trailer to "$1"
pack_trailer () {
	test-sha1 -b <"$1" >trailer.tmp &&
	cat trailer.tmp >>"$1" &&
	rm -f trailer.tmp
}

# Remove any existing packs to make sure that
# whatever we index next will be the pack that we
# actually use.
clear_packs () {
	rm -f .git/objects/pack/*
}
back to top