[Freeipa-devel] [PATCH] 1 Do lazy initializiation ipalib

[Jan Cholasta]

Dne 2.11.2011 16:11, Alexander Bokovoy napsal(a):
> On Wed, 02 Nov 2011, Jan Cholasta wrote:
>> I see a number of problems with the patch:
>>
>>    * Only Command subclasses are finalized (that might be the reason
>> why it is so fast)
>>    * You assume that the first operation on a plugin instance is a
>> call on the args/options/params namespaces, but there is no
>> guarantee that it will be
>>    * The whole approach is error-prone, as it requires the programmer
>> to carefully setup the attributes so that the plugin can be properly
>> finalized (this should be done automatically, so that every plugin
>> is guaranteed to be finalized without complicated setup)
> Perhaps you need to look at why finalize() is there at all. We have
> certain properties that are set only during finalize() method
> execution. If something cannot be performed without accessing those
> properties, it cannot be done before finalize() is performed.
> Anything else is allowed. So it boils down to being able to intercept
> the access to those properties that change their value in effect of
> finalize() call.
>
> What this all means is if a plugin writer has something in mind
> when changing properties in his/her re-implementation of finalize()
> method, it is simple to mark up those properties as such and this
> patch gives you a simple process and means to do so.
>
> Callable instances are a consequence of the above --
> Command.__call__() does use properties that are changed due to
> finalize() being run. In fact, there are so many places in FreeIPA
> where we simply expect that foo.args/params/output_params/output is
> both iterable and callable instance that it is not even funny.
>
> Now, the process established by the proposed patch is actually
> dependent only on the fact that bound instance has finalize() method.
> This is quite generic and can be used for all other types of objects.
>

The real problem is in the API class so it should be fixed there, not 
worked around in Plugin subclasses.

-- 
Jan Cholasta