IPv6 addresses can start with ":", for which QDir::isAbsolute() would
always return true (QResourceFileEngine::isRelativePath() returns
constant false) and would trip the calculation for local files.
Similarly, IPv6 addresses can start with strings that look like Windows
drives: "a:", "b:", "c:", "d:", "e:" and "f:" (though not today, as
those address blocks are unassigned). Since a valid IPv6 address will
definitely require at least one more colon and Windows file names cannot
contain ':', there's no ambiguity: a valid IPv6 address is never a valid
file on Windows.
This resolves the ambiguity in favor of IPv6 for Unix filenames (which
can contain a colon) and in case of an URL containing scheme, relative
path and no authority ("dead:beef::" for example could have been parsed
as scheme() == "dead" and path() == "beef::").
Task-number: QTBUG-41089
Change-Id: Id9119af1acf8a75a786519af3b48b4ca3dbf3719
Reviewed-by: David Faure <david.faure@kdab.com>
0c32af08a6