XPath.parse should always return array

[pboling]

According to documentation:

    # Returns an array of nodes matching a given XPath.

It should always be an array, which could be empty.

But in the code it sometimes returns nil.

[tompng]

Can you describe when parse returns nil ?

I looked at the code but it looks like parse always return an array or raise an error.
parse seems to return array([]) or match(enable_cache{match(path_stack, node)})
match seems to always return an array: unnode(result).uniq or [result]

Perhaps this bug only exists in #261

- node.document.__send__(:enable_cache) do # returns array or raise
+ node.document&.__send__(:enable_cache) do # returns array or nil

I think it should be

if node.document
  node.document.__send__(:enable_cache) do
    do_something # with cache
  end
else
  do_something # without cache
end

[pboling]

Yes, that's correct. I'll make that change when I chop #261 into parts.