CLJS-2844: [spec] Add support for undefining a spec

Author: mfikes

src/main/cljs/cljs/spec/alpha.cljc

@@ -61,9 +61,10 @@
     (symbol (str ana/*cljs-ns*) (str s))))
 
 (defmacro def
-  "Given a namespace-qualified keyword or resolveable symbol k, and a spec,
-   spec-name, predicate or regex-op makes an entry in the registry mapping k to
-   the spec"
+  "Given a namespace-qualified keyword or resolveable symbol k, and a
+  spec, spec-name, predicate or regex-op makes an entry in the
+  registry mapping k to the spec. Use nil to remove an entry in
+  the registry for k."
   [k spec-form]
   (let [k    (if (symbol? k) (ns-qualify &env k) k)
         form (res &env spec-form)]

src/main/cljs/cljs/spec/alpha.cljs

@@ -294,11 +294,13 @@
   "Do not call this directly, use 'def'"
   [k form spec]
   (assert (c/and (ident? k) (namespace k)) "k must be namespaced keyword or resolveable symbol")
-  (let [spec (if (c/or (spec? spec) (regex? spec) (get @registry-ref spec))
-               spec
-               (spec-impl form spec nil nil))]
-    (swap! registry-ref assoc k (with-name spec k))
-    k))
+  (if (nil? spec)
+    (swap! registry-ref dissoc k)
+    (let [spec (if (c/or (spec? spec) (regex? spec) (get @registry-ref spec))
+                 spec
+                 (spec-impl form spec nil nil))]
+      (swap! registry-ref assoc k (with-name spec k))))
+  k)
 
 (defn registry
   "returns the registry map, prefer 'get-spec' to lookup a spec by name"

src/test/cljs/cljs/spec_test.cljs

@@ -307,6 +307,11 @@
 (deftest keys-explain-pred
   (is (= 'cljs.core/map? (-> (s/explain-data (s/keys :req [::x]) :a) ::s/problems first :pred))))
 
+(deftest remove-def
+  (is (= ::ABC (s/def ::ABC string?)))
+  (is (= ::ABC (s/def ::ABC nil)))
+  (is (nil? (s/get-spec ::ABC))))
+
 (s/fdef foo.bar/cljs-2275
   :args (s/cat :k keyword?)
   :ret  string?)