Bug 27325

Summary:	GetContactAttributes() is specified to be needlessly fascist about interfaces
Product:	Telepathy	Reporter:	Will Thompson <will>
Component:	tp-spec	Assignee:	Telepathy bugs list <telepathy-bugs>
Status:	RESOLVED FIXED	QA Contact:	Telepathy bugs list <telepathy-bugs>
Severity:	normal
Priority:	medium	Keywords:	patch
Version:	git master
Hardware:	Other
OS:	All
Whiteboard:	review+
i915 platform:		i915 features:
Bug Depends on:
Bug Blocks:	27374

Description Will Thompson 2010-03-26 04:02:59 UTC

From the definition of GetContactAttributes():

> It is an error to request interfaces that are not supported by this
> Connection (i.e. mentioned in the ContactAttributeInterfaces
> property).
>
> | This makes it possible to distinguish between interfaces for which
> | the Connection has nothing to say (e.g. we don't know the avatar
> | tokens of any of the contacts, so we omitted them all), and interfaces
> | for which this API isn't supported.

This is needlessly pedantic. If we had instead said that the CM must
ignore interfaces which aren't supported on the Contacts interface, then
client code that does care could still check ContactAttributeInterfaces
to distinguish those two cases, and client code that doesn't care
wouldn't have to mess around checking the list of interfaces it passes
to GetContactAttributes().

Comment 1 Will Thompson 2010-03-26 04:59:05 UTC

Here is a branch for this spec change: http://git.collabora.co.uk/?p=user/wjt/telepathy-spec-wjt.git;a=shortlog;h=refs/heads/fd.o-27325-GetContactAttributes-tolerance

Here is the HTML of the method's new wording: http://people.freedesktop.org/~wjt/telepathy-spec-fd_o_27325_GetContactAttributes_tolerance/spec/org.freedesktop.Telepathy.Connection.Interface.Contacts.html#org.freedesktop.Telepathy.Connection.Interface.Contacts.GetContactAttributes

Here is a branch to make TpContactsMixin tolerant: http://git.collabora.co.uk/?p=user/wjt/telepathy-glib.git;a=shortlog;h=refs/heads/fd.o-27325-GetContactAttributes-tolerance

Here is an untested branch to make telepathy-butterfly tolerant: http://git.collabora.co.uk/?p=user/wjt/telepathy-butterfly.git;a=shortlog;h=refs/heads/fd.o-27325-GetContactAttributes-tolerance

Comment 2 Simon McVittie 2010-03-29 05:33:15 UTC

I think Rob was in favour of it being this fascist, but I can't remember why...

Comment 3 Robert McQueen 2010-03-29 05:41:18 UTC

(In reply to comment #2)
> I think Rob was in favour of it being this fascist, but I can't remember why...

If so, I was wrong due to lack of any supporting rationale recorded, that any of us can remember, or that we can think of. I apologise, and give free leave to reduce fascism wherever possible in the interests of reducing roundtrips. The reason /may/ have been not being able to tell the difference between supported-but-not-known-for-this-contact versus not-supported. But for simple use cases, you don't care about this.

Comment 4 Simon McVittie 2010-03-29 05:54:48 UTC

review+, in that case. Considering this to have been specmeet-approved since most of the usual specmeet cabal have been involved.

Non-review-blocker:

> +                logger.debug("Ignoring unsupported interface " + interface)

logger.debug("Ignoring unsupported interface %s", interface) is conventional (if called with more than one argument, logger methods interpolate their arguments into the first one as if via %).

Comment 5 Will Thompson 2010-03-30 11:56:53 UTC

Spec and tp-glib bits merged; butterfly bit cloned as bug 27374.

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