git/Documentation/merge-strategies.txt

MERGE STRATEGIES
----------------

resolve::
	This can only resolve two heads (i.e. the current branch
	and another branch you pulled from) using 3-way merge
	algorithm.  It tries to carefully detect criss-cross
	merge ambiguities and is considered generally safe and
	fast.

recursive::
	This can only resolve two heads using 3-way merge
	algorithm.  When there are more than one common
	ancestors that can be used for 3-way merge, it creates a
	merged tree of the common ancestors and uses that as
	the reference tree for the 3-way merge.  This has been
	reported to result in fewer merge conflicts without
	causing mis-merges by tests done on actual merge commits
	taken from Linux 2.6 kernel development history.
	Additionally this can detect and handle merges involving
	renames.  This is the default merge strategy when
	pulling or merging one branch.

octopus::
	This resolves more than two-head case, but refuses to do
	complex merge that needs manual resolution.  It is
	primarily meant to be used for bundling topic branch
	heads together.  This is the default merge strategy when
	pulling or merging more than one branches.

ours::
	This resolves any number of heads, but the result of the
	merge is always the current branch head.  It is meant to
	be used to supersede old development history of side
	branches.

subtree::
	This is a modified recursive strategy. When merging trees A and
	B, if B corresponds to a subtree of A, B is first adjusted to
	match the tree structure of A, instead of reading the trees at
	the same level. This adjustment is also done to the common
	ancestor tree.