CLJ version checks before require

Author: fogus

src/main/clojure/clojure/core/async.clj

@@ -83,6 +83,9 @@ IOC and vthread code.
            [java.util.concurrent ThreadLocalRandom]
            [java.util Arrays ArrayList]))
 
+(when (not dispatch/lazy-loading-supported?)
+  (require 'clojure.core.async.impl.go))
+
 (alias 'core 'clojure.core)
 
 (set! *warn-on-reflection* false)
@@ -512,8 +515,9 @@ IOC and vthread code.
     (when ret @ret)))
 
 (defn- dynamic-require [nsym]
-  (dispatch/ensure-clojure-version! 1 12 3)
-  (require nsym))
+  (when (and dispatch/lazy-loading-supported?
+             (not (contains? @@#'clojure.core/*loaded-libs* nsym)))
+    (#'clojure.core/serialized-require nsym)))
 
 (defn- go* [body env]
   (cond (and (not dispatch/virtual-threads-available?)

src/main/clojure/clojure/core/async/impl/dispatch.clj

@@ -73,15 +73,12 @@
   [workload]
   (Executors/newCachedThreadPool (counted-thread-factory (str "async-" (name workload) "-%d") true)))
 
-(def ensure-clojure-version!
-  (memoize
-   (fn [maj min incr]
-     (let [{:keys [major minor incremental]} *clojure-version*]
-       (when (neg? (compare [major minor incremental] [maj min incr]))
-         (throw (ex-info (str "core.async go block expander requires Clojure version ≥"
-                              maj "." min "." incr
-                              " to load")
-                         {:clojure-version *clojure-version*})))))))
+(defn at-least-clojure-version?
+  [[maj min incr]]
+  (let [{:keys [major minor incremental]} *clojure-version*]
+    (not (neg? (compare [major minor incremental] [maj min incr])))))
+
+(def lazy-loading-supported? (at-least-clojure-version? [1 12 3]))
 
 (def virtual-threads-available?
   (try