On 21 Leden 2012, 18:20, Dimitri Fontaine wrote:
> Hi,
>
> Thank you for reviewing this patch!
>
> Hitoshi Harada <umi.tanuki@gmail.com> writes:
>>
>> Next, some questions:
>> - Why is the finer dependency needed? Do you have tangible example
>> that struggles with the dependency granularity? I feel so good about
>> the existing dependency on extension as an extension developer of
>> several ones.
>
> The problem is not yet very apparent only because extensions are very
> new. The main thing we address with this patch is depending on a feature
> that appeared while developing an extension or that gets removed down
> the line. It allows to depend on features and avoid needing to compare
> version numbers and maintain a list of which version number is providing
> which feature.
>
> This feature has been asked by several extension users, beginning even
> before 9.1 got released.
It's also about several extension providing the same sort of functionality
implemented in different ways. Think about extensions that allow you to
send e-mails right from the database. One could do that directly, the
other one could implement queuing, another one could be optimized for a
specific SMTP server. With features, you could just say 'require = mail'
and use the extension that's installed. Yes, this needs a common API.
I personally see this as a major step towards fully-fledged package
management, similar to those available in modern Linux distributions (apt,
yum, portage, ...).
Tomas
