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 a 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 a 3-way merge
	algorithm.  When there is more than one common
	ancestor 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 cases with more than two heads, but refuses to do
	a 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 branch.

ours::
	This resolves any number of heads, but the resulting tree of the
	merge is always that of the current branch head, effectively
	ignoring all changes from all other branches.  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.