считывает информацию о дереве в индекс (Reads tree information into the index)
Описание (Description)
Reads the tree information given by <tree-ish> into the index,
but does not actually update any of the files it "caches". (see:
git-checkout-index(1))
Optionally, it can merge a tree into the index, perform a
fast-forward (i.e. 2-way) merge, or a 3-way merge, with the -m
flag. When used with -m, the -u flag causes it to also update the
files in the work tree with the result of the merge.
Trivial merges are done by git read-tree itself. Only conflicting
paths will be in unmerged state when git read-tree returns.
