Pcache overlay bug or undocumented "feature"?

["Daniel Montero Motilla" <damonmo@gmail.com>]

Hi, I'm obtaining a strange (almost for me) behaviour with pcache
overlay (openldap 2.3.27), I have a configuration similar to this one:

proxyattrset 0 uid cn sn mail description
proxyattrset 1 cn description
proxytemplate (&(objectClass=)(uid=)) 0 3600
proxytemplate (&(objectClass=)(cn=)) 1 3600

With this configuration, I perform this search:

(&(objectClass=groupOfNames)(cn=mygroup)) cn description

but I obtain "NOT ANSWERABLE" and "NOT CACHEABLE".

Digging on pcache.c, I see that the problem is that 'get_attr_set'
function doesn't look for a proxyattrset that _exactly_ matches with
my search attribute set, it instead looks for a proxyattrset that is a
_superset_ of the search attribute set.

On my example, my search attribute set (cn, description) is a subset
of proxyattrset '0', so 'get_attr_set' returns '0'. Then, the
application looks for a proxytemplate whose proxyattrset equals the
one obtained with 'get_attr_set' (0), so it obtains the template
'(&(objectClass=)(uid=))' and compares it with my search template
'(&(objectClass=)(cn=))', so I get 'NOT CACHEABLE'.

As a workaround I have inverted the proxyattrset index numbers so
'get_attr_set' finds first the most specific proxyattrset, but i'm
curious about if this behaviour is the intended one or if I should
fill an ITS with a patch (the change in code would be minimal), what
do you think?

Thanks,

Dani