MicroKernel additionalArgs behavior definition

[hammett]

I wasnt sure what was the additionalArgs behavior when going down in
the dependency chain, so I added a test, which failed but that's
another story.

Seems that the current behavior is to propagate the additionalArgs
which makes me a bit uncomfortable. Think about it: every parameter
set on that dictionary will be matched by name, without a scope. This
has a great potential of name clashing leading to unexpected behavior.
I have commented the code that propagates it (CreationContext
constructor that takes a parent context) but even that isn't good
enough.

As an user I'd expect a very well defined and predictable behavior. So
for a usage like

var sender = container.Resolve<IEmailSender, new { Host = "somehost" }>();

I would expect that the host of the IEmailSender will be the only one
affected, not any dependency that the email sender happens to have..
does that make sense?

Currently I believe this is the behavior I left but more tests or
thinking are appreciated. The construction graph is inverted if
dependencies are set through constructors but I'd hope that the root
CreationContext will be tied to the root component/default handler.

Thoughts?

--
Cheers,
hammett
http://hammett.castleproject.org/

[Ayende Rahien]

It is actually very useful to be able to give a dependency for anything on the chain. I agree that matching by name is... not ideal, but I don't see any other choice.
Imagine:

var sender = container.Resolve<INotificationSender>(new { Host = "somehost" });

Where INotificationSender depends on IEmailSender, which depends on Host.

[hammett]

> var sender = container.Resolve<INotificationSender>(new { Host = "somehost"
> });

This is very cryptic. I'd argue that it only makes sense to whomever
implemented the feature. If there's a way to pass in the call the
target component that you want to override the parameters, I'd be more
comfortable with this feature.

[Ayende Rahien]

The only thing that I can think of is something like:

var sender = container.Resolve<INotificationSender>(new ProvideHostArgument("somehost"));

So we pass some ISubDependencyResolver() that apply only for this resolution.

[Jonathon Rossi]

Do you mean something like this:

var sender = container.Resolve<INotificationSender>(

    new Dependency<IEmailSender>(new { Host = "somehost" })
);

--
Jonathon Rossi

[Ayende Rahien]

Hm,
That might be a great idea, yes.

[Germán Schuager]

This is almost the same but with a fluent touch:

var sender = container.Resolve<INotificationSender>(

    Dependencies.For<IEmailSender>(new { Host = "somehost" })
);