`CatalogTool.searchResults` ignores `effective`/`expires`/`allowedRolesAndUsers` restrictions in the base query

[d-maurer]

For unpriviledged users, CatalogTool.searchResults rewrites the base query to add additional restrictions. But it is not careful enough: the restricted query can be more permissive than the unrestricted one -- potentially resulting in too many hits. Potentially affected are base queries with expires, effective or allowedRolesAndUsers subqueries. For expires and effective subqueries the problem occurs only when they are not specified by keyword arguments (but in the REQUEST argument). The following example demontrates the problem:

>>> from Products.ZCatalog.Catalog import Catalog
>>> from Products.CMFCore.CatalogTool import CatalogTool
>>> from DateTime.DateTime import DateTime
>>> from pprint import pprint as pp
>>> 
>>> def trace(f):
...   """decorator to trace the effectively executed query."""
...   f = getattr(f, "__func__", f)
...   def traced(*args, **kw):
...     r = f(*args, **kw)
...     print("effective query:")
...     pp(r)
...     return r
...   return traced
... 
>>> # intrument `Catalog.merge_query_args` to see what happens
>>> Catalog.merge_query_args = trace(Catalog.merge_query_args)
>>> 
>>> c = CatalogTool()
>>> 
>>> def check(REQUEST=None, **kw):
...   try:
...     c(REQUEST, **kw)
...   except Exception: pass  # we are not really interested in the result
... 
>>> dt = DateTime(0)
>>> 
>>> # this works correctly
>>> check(effective=dict(query=dt, range="max"))
effective query:
{'allowedRolesAndUsers': ['Anonymous', 'Anonymous', 'user:None'],
 'effective': {'query': DateTime('1970/01/01 01:00:00 GMT+1'), 'range': 'max'},
 'expires': {'query': DateTime('2019/03/15 18:23:9.599377 GMT+1'),
             'range': 'min'}}
>>> 
>>> # this should be equivalent - but is not:
>>> #   the `effective` subquery is more permissive than it should be
>>> check(dict(effective=dict(query=dt, range="max")))
effective query:
{'allowedRolesAndUsers': ['Anonymous', 'Anonymous', 'user:None'],
 'effective': {'query': DateTime('2019/03/15 18:23:40.451992 GMT+1'),
               'range': 'max'},
 'expires': {'query': DateTime('2019/03/15 18:23:40.451992 GMT+1'),
             'range': 'min'}}

[icemac]

A PR is welcome.