Move ::dependencies meta at the system level about component HOT 3 CLOSED

Hi @frankiesardo
I hope don't make noise here, but if I fully got your first need/requirement:

If dependencies were stored at the system level I would only need to declare them once. I realise this would break component/using but to me the dependency tree makes more sense as a system property, rather than as a component property.

do you intend something like that?

(ns production)

(defn get-system-map []
  (component/system-map
          :foo (Foo. nil)
          :bar (Bar.)))

(defn assoc-deps [system]
  (component/system-using system {:foo [:bar]}))

(def prod-system
  (-> (get-system-map)
      assoc-deps))

(component/start prod-system)

(ns developement
  (:require [production :refer (get-system-map assoc-deps)]))

(def dev-system
  (-> (get-system-map)
      (assoc :foo (DevFoo.))
      assoc-deps))

(component/start dev-system)

And, if you expand a bit your component dependency scenario and concept related maybe I can try to hep too

Foo could be created directly passing Bar; only in a system where :bar is part of the dependency tree should Foo declare it as a dependency.

from component.

I mean, there's nothing you can't do already. I usually end up with something like:

(defn assoc-with-meta [m k v]
  (let [meta (meta (k m))]
    (assoc m k (with-meta v meta))))

(def dev-system (assoc-with-meta system :foo (DevFoo.))) ;; yay!

I guess it was more an issue/question about the library design. I would have expected vanilla assoc to "just work™".

If component/using needs to be supported as a use case, then component/system-map could simply attach to the SystemMap meta the result of merging the dependencies of all its components.

from component.

I definitely think of dependencies as a property of the individual component, not the system as a whole.

For example, a mock or stub component used for testing will often have different dependencies from the "real" component it replaces.

If your dependencies are static, you can still call system-using after you construct your dev-system.

from component.