CLJS-2269: Warn on top level code split loads

cljs.loader/load is now a macro that passes in the module that
initiated the load. This is validated to check that it is already
loaded to avoid common misunderstanding about how loader is intended
to be used.

Author: swannodette

src/main/cljs/cljs/loader.clj

@@ -0,0 +1,30 @@
+;   Copyright (c) Rich Hickey. All rights reserved.
+;   The use and distribution terms for this software are covered by the
+;   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+;   which can be found in the file epl-v10.html at the root of this distribution.
+;   By using this software in any fashion, you are agreeing to be bound by
+;   the terms of this license.
+;   You must not remove this notice, or any other, from this software
+
+(ns cljs.loader
+  (:refer-clojure :exclude [load])
+  (:require [cljs.module-graph :as mg]
+            [cljs.analyzer :as ana]
+            [cljs.analyzer.api :as ana-api]))
+
+(defn load-expr
+  ([env module-name]
+   (load-expr env module-name nil))
+  ([env module-name cb]
+   (let [sinfo  (ana/srce-info env)
+         loader (mg/module-for (-> env :ns :name)
+                  (:modules (ana-api/get-options)))]
+     `(cljs.loader/load* ~module-name ~loader ~cb))))
+
+(defmacro load
+  "Load a module. module-name should be a keyword matching a :modules module
+   definition."
+  ([module-name]
+   (load-expr &env module-name))
+  ([module-name cb]
+   (load-expr &env module-name cb)))

src/main/cljs/cljs/loader.cljs

@@ -1,4 +1,13 @@
+;   Copyright (c) Rich Hickey. All rights reserved.
+;   The use and distribution terms for this software are covered by the
+;   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+;   which can be found in the file epl-v10.html at the root of this distribution.
+;   By using this software in any fashion, you are agreeing to be bound by
+;   the terms of this license.
+;   You must not remove this notice, or any other, from this software
+
 (ns cljs.loader
+  (:require-macros cljs.loader)
   (:require [goog.object :as gobj])
   (:import [goog.module ModuleLoader]
            [goog.module ModuleManager]))
@@ -33,14 +42,30 @@
 (.setAllModuleInfo *module-manager* (to-js module-infos))
 (.setModuleUris *module-manager* (to-js module-uris))
 
-(defn load
+(defn loaded?
+  "Return true if modules is loaded. module-name should be a keyword matching
+   a :modules module definition."
+  [module-name]
+  (assert (contains? module-infos module-name)
+    (str "Module " module-name " does not exist"))
+  (let [mname (-> module-name name munge)
+        module (.getModuleInfo *module-manager* mname)]
+    (when (some? module)
+      (.isLoaded module))))
+
+(defn load*
   "Load a module. module-name should be a keyword matching a :modules module
    definition."
   ([module-name]
-    (load module-name nil))
-  ([module-name cb]
+    (throw (js/Error. "Invalid load call, must provide loader argument")))
+  ([module-name loader]
+    (load* module-name loader nil))
+  ([module-name loader cb]
    (assert (contains? module-infos module-name)
      (str "Module " module-name " does not exist"))
+   (assert (loaded? loader)
+     (str "Module " loader " not fully loaded, but attempted to "
+          "load module " module-name))
    (let [mname (-> module-name name munge)]
      (if-not (nil? cb)
        (.execOnLoad *module-manager* mname cb)
@@ -60,17 +85,6 @@
       (.setLoaded *module-manager* (munge-kw x)))
     (.setLoaded *module-manager* (munge-kw module-name))))
 
-(defn loaded?
-  "Return true if modules is loaded. module-name should be a keyword matching
-   a :modules module definition."
-  [module-name]
-  (assert (contains? module-infos module-name)
-          (str "Module " module-name " does not exist"))
-  (let [mname (-> module-name name munge)
-        module (.getModuleInfo *module-manager* mname)]
-    (when (some? module)
-      (.isLoaded module))))
-
 (defn prefetch
   "Prefetch a module. module-name should be a keyword matching a :modules
   module definition. Will download the module but not evaluate it. To