Comment 13 for bug 1448990

Reviewed: https://review.openstack.org/177950
Committed: https://git.openstack.org/cgit/stackforge/yaql/commit/?id=f59e459d04cc83ca99d76eebf2a4a3fef20995c3
Submitter: Jenkins
Branch: master

commit f59e459d04cc83ca99d76eebf2a4a3fef20995c3
Author: Alexander Tivelkov <email address hidden>
Date: Mon Apr 27 22:48:13 2015 +0300

    Fixed compatibility with ply 3.6

    In newly released ply 3.6 function yacc() of the yacc module no longer
    accepts 'None' as the 'tabmodule' keyword parameter and expects a valid
    string instead.
    Meanwhile, the tabmodule file is not created unless write_tables is set
    to True.

    This patchset provides such a string and ensures that it is unique.
    Omitting the 'tabmodule' parameter at all could possibly do the trick as
    well, however that would mean that the parameter would get its default
    value - 'parsetab' - which could potentially lead to a minor security
    vulnerability if the the system somehow had got a malicious 'parsetab'
    module (as yacc attempts to load the generated tables from module
    specified by 'tabmodule' before proceeding to grammar generation).
    Assigning a random value to this parameter prevents such a situation.

    This patch also fixes the ply requirement to <=3.6 to prevent future
    gate breakages due to unexpected changes in ply.

    Closes-Bug: #1448990

    Change-Id: I4364729223521864f7cda5a932503d7ce1b6fa36