all_strategies='recur recursive octopus resolve stupid ours subtree'
all_strategies="$all_strategies recursive-ours recursive-theirs"
+not_strategies='base file index tree'
default_twohead_strategies='recursive'
default_octopus_strategies='octopus'
no_fast_forward_strategies='subtree ours'
use_strategies="$use_strategies$1 "
;;
*)
+ case " $not_strategies " in
+ *" $1 "*)
+ false
+ esac &&
type "git-merge-$1" >/dev/null 2>&1 ||
die "available strategies are: $all_strategies"
use_strategies="$use_strategies$1 "