merge: add a config to allow conflict-free merge of changes on adjacent lines
This change adds a config to make it no longer a conflict to merge changes
made on adjacent lines.
The reason these changes are considered a conflict is that there's no
region of text at the relevant position (sync region) that's kept unchanged
by both sides of the merge.
The problem can be solved by making the sync regions being a bit more
powerful: we can keep a 0-length sync region if we find that
a block unchanged by one side is ajacent to a block unchanged by the
other side.
Since these 0-length sync regions are emitted using the ~same algorithm
as the normal non-empty sync regions, this change involves no arbitrary
decisions and I expect it to work pretty well.
0-length sync regions do create an ambiguity in a special case where two
pairs of adjacent regions "meet" at the same point. This corresponds to
an insertion made at the same place by the two sides of the merge, and
this still results in a conflict.
# __init__.py - Startup and module loading logic for Mercurial.
#
# Copyright 2015 Gregory Szorc <gregory.szorc@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import annotations
# Allow 'from mercurial import demandimport' to keep working.
import hgdemandimport
demandimport = hgdemandimport