Close #472: don't allow composite schemas to be cached

Author: frenchy64

CHANGELOG.md

@@ -6,6 +6,7 @@ See also: [compojure-api 1.1.x changelog](./CHANGELOG-1.1.x.md)
   * Migration instructions: run your program and fix the error messages, which will provide specific instructions.
   * to circumvent this change, set `-Dcompojure.api.middleware.global-default-formatter=:muuntaja`
   * stable 2.x will default `:formatter` to `:ring-middleware-format`
+* [#472](https://github.com/metosin/compojure-api/issues/472): Fix potential memory leak involving schemas being cached in the multimethod default cache
 
 ## 2.0.0-alpha33 (2024-04-30)
 * Throw an error on malformed `:{body,query,headers}`, in particular if anything other than 2 elements was provided

src/compojure/api/coercion/schema.clj

@@ -32,7 +32,11 @@
   (common/fifo-memoize sc/coercer 1000))
 
 ;; don't use coercion for certain types
-(defmulti coerce-response? identity :default ::default)
+(defmulti coerce-response? #(if (or (class? %)
+                                    (keyword? %))
+                              %
+                              ::default)
+  :default ::default)
 (defmethod coerce-response? ::default [_] true)
 (defmethod coerce-response? File [_] false)
 

test/compojure/api/coercion/schema_coercion_test.clj

@@ -285,3 +285,10 @@
 
     (testing "generates valid swagger spec"
       (is (validator/validate app)))))
+
+(def some-spec (s/conditional
+                 identity s/Int))
+(defmethod cs/coerce-response? some-spec [_] false)
+
+(deftest coerce-response-memory-leak-test
+  (is (true? (cs/coerce-response? some-spec))))