[python-ldap] segfault/Abort for operations with unbound connection

[Michael Ströder]

HI!

(please stay on python-ldap list so others comment as well)

Space One wrote:
> 
> Am 26.01.2016 um 16:21 schrieb Michael Ströder:
>> Space One wrote:
>>> AttributeError is IMHO not good, please better raise ldap.SERVER_DOWN so
>>> that one can handle it.
>> I consider ldap.SERVER_DOWN to be inappropriate in this case because it
>> indicates an error the application can recover from by proper reconnect.
>>
>> But in case the application calls some LDAPObject method *after* unbinding then
>> the application's code has to be fixed. This is a different case!
>
> We are speaking about ldap.ldapobject.ReconnectLDAPObject, right?

Not limited to ReconnectLDAPObject.

> This class somehow unbind()s itself.

I never experienced such a seg fault when using ReconnectLDAPObject and I'm
using it a lot. Therefore I assume there's no problem inside this class.
Especially it won't call any LDAPObject method after internal unbind without
internally setting up new connection object.

> If you aren't okay with ldap.SERVER_DOWN please don't use AttributeError
> but some new exception like ldap.UNBOUND_CONNECTION.
> 
> As the intial thread says I want a way to clearly be able to
> differentitate if the connection is still valid and handle things if
> not. AttributeError would not be nice in that scenario as I don't want
> to catch all AttributeErrors.

Your application MUST NOT catch this exception and simply re-try!

Your application MUST avoid to use an LDAPObject instance after calling
LDAPObject.unbind_ext() and friends! So if this (unhandled) exception ever
happens it indicates a bug in your application logic and you have to fix your
calling code.

The only thing python-ldap did wrong is the seg fault.

Ciao, Michael.

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