I found this while working on T249167. Searching for something like
"[" or copy-pasting something like "[[Foo]]" simply returns
*all* pages, in alphabetical order. This is unexpected.
A worst-case example is
api.php?action=opensearch&search=Test
vs.
api.php?action=opensearch&search=Test]
While the first example behaves as expected (it will either find
pages with this prefix, or nothing if there is none), the second
will return the entire database.
Expected: It should either find nothing, or pages that start with
"Test".
Note this patch intentionally does not fix one edge-case: Input
like "[" will still return all pages. I left this untouched for
now because it might be used as a feature somewhere.
Note you can not test this on Wikimedia wikis because they don't
use this search backend. Which is just another reason to fix this.
On Wikipedia, searching for "[[Test]]" works just fine.
Change-Id: I877297f69ca560460766e1035e02b009919054e1
5f9a85f36d