feat: add deps w/ :systemic.core/dependencies meta

You can now add dependencies to a variable (eg. function metadata) w/
the :systemic.core/dependencies annotation to have it be added as a
transitive dependency inside `defsys` calls.

Author: rschmukler

src/systemic/internal.clj

@@ -59,12 +59,15 @@
   (let [result (transient #{})]
     (walk/postwalk
       (fn [item]
-        (when-some [qualified-sym (when (symbol? item)
-                                    (let [resolved (ns-resolve ns item)]
-                                      (cond
-                                        (var? resolved)   (symbol resolved)
-                                        (nil? resolved)   nil
-                                        (class? resolved) nil)))]
+        (let [resolved (when (symbol? item)
+                         (ns-resolve ns item))
+              qualified-sym (cond
+                              (var? resolved)   (symbol resolved)
+                              (nil? resolved)   nil
+                              (class? resolved) nil)]
+          (doseq [meta-dep (:systemic.core/dependencies (meta resolved))
+                  dep      (find-dependencies ns meta-dep registry)]
+            (conj! result dep))
           (when (contains? registry qualified-sym)
             (conj! result qualified-sym))))
       form)

test/systemic/core_test.clj

@@ -44,6 +44,12 @@
   This will break if we rename this file but at least it's defined in just one place."
   'systemic.core-test/*config*)
 
+(defn dependent-fn
+  "Testing"
+  {:systemic.core/dependencies #{`*config*}}
+  []
+  5)
+
 (deftest find-dependencies-test
   (testing "correctly identifies dependencies in a body"
     (is (= #{registry-symbol}
@@ -53,7 +59,13 @@
     (is (= #{} (internal/find-dependencies (-> *ns* str symbol) `(try 5
                                                                       (catch Exception e
                                                                         nil))
-                                           @sut/*registry*)))))
+                                           @sut/*registry*))))
+
+  (testing "handling metadata"
+    (is (= #{registry-symbol}
+           (internal/find-dependencies (-> *ns* str symbol)
+                                       `(dependent-fn)
+                                       @sut/*registry*)))))
 
 (deftest defsys-test
   (testing "registers it in the registry"