fix ESM .js code referencing other ESM .js code

Closure assumes that the final output is all in the same scope
but for node that isn't true currently. So instead of trying to
change the way Closure rewrites we just collect the names it
creates and lift those into the global scope when needed.

only really affected watch/compile builds. release doesn't have
this problem.

fixes #836
fixes #521

src/dev/demo/more-es6.js

@@ -3,4 +3,6 @@ function bar(x) {
   return x;
 };
 
-export { bar };
+let foo = 1;
+
+export { bar, foo };

src/dev/demo/script.cljs

@@ -4,14 +4,9 @@
     ["request" :as req]
     ;; ["./cjs.js" :as cjs]
     [demo.js-class :refer (Foo)]
+    ["./es6.js" :as es6]
     ["which" :as which]))
 
-;; (js/console.log "cjs" cjs)
-
-(js/console.log "Foo" Foo)
-
-(prn [:goog.global js/goog.global.setTimeout])
-
 (req "https://www.google.com"
   (fn [error res body]
     (prn [:error error])
@@ -29,6 +24,7 @@
 
 (defn main [& args]
   (js/console.log "starting server")
+  (es6/foo "bar")
   (let [server (http/createServer #(request-handler %1 %2))]
 
     (tap> [:hello-world js/process.env])

src/main/shadow/build/closure.clj

@@ -48,6 +48,11 @@
             (.getDeclaredField "injectedLibraries"))
     (.setAccessible true)))
 
+(def own-symbols-field
+  (doto (-> (Class/forName "com.google.javascript.jscomp.SymbolTable$SymbolScope")
+            (.getDeclaredField "ownSymbols"))
+    (.setAccessible true)))
+
 ;;;
 ;;; partially taken from cljs/closure.clj
 ;;; removed the things we don't need
@@ -1021,6 +1026,11 @@
       (keys)
       (set)))
 
+(defn get-own-symbol-names [symbol-scope]
+  (-> (.get own-symbols-field symbol-scope)
+      (keys)
+      (set)))
+
 (defn dump-closure-inputs [state externs js-mods compiler-options]
   (doseq [extern externs]
     ;; externs have weird filenames and we don't need to keep folders intact
@@ -1526,7 +1536,15 @@
         (.getSourceMap cc)
 
         injected-libs
-        (get-injected-libs cc)]
+        (get-injected-libs cc)
+
+        global-symbol-names
+        (-> (.buildKnownSymbolTable cc)
+            (.getGlobalScope)
+            (get-own-symbol-names))
+
+        eval-in-global-scope
+        (get state ::output/eval-in-global-scope true)]
 
     (throw-errors! state cc result)
 
@@ -1539,6 +1557,7 @@
 
 
             (let [name (.getSourceFileName source-node)]
+
               (cond
                 (= polyfill-name name)
                 state
@@ -1597,6 +1616,18 @@
                           js
                           (str shadow-js-prefix js)
 
+                          ;; closure creates var bar$$module$some$file
+                          ;; for export let bar = 1 in /some/file.js
+                          ;; which is fine if everything is in the same global scope
+                          ;; but for node they are in their own local scope so we need to lift them into the global scope later
+                          sym-str
+                          (str ns)
+
+                          names-in-this-file
+                          (->> global-symbol-names
+                               (filter #(str/ends-with? % sym-str))
+                               (set))
+
                           sm-json
                           (.toString sw)
 
@@ -1618,7 +1649,18 @@
                                                ;; var module$demo$reducers$profile = ...
                                                ;; FIXME: not sure if it will always emit this exact pattern
                                                (str/includes? js (str "var " ns " =")))
-                                      (str "\n$CLJS." ns "=" ns ";")))
+                                      (str "\n$CLJS." ns "=" ns ";"))
+
+                                    ;; actually lift the names into the global scope if needed
+                                    ;; normally not required since everything is in the same scope
+                                    ;; mostly node will have its own scope per file though
+                                    (when (and (= :dev mode) (not eval-in-global-scope) (seq names-in-this-file))
+                                      (str "\n"
+                                           (->> names-in-this-file
+                                                (map #(str "global." % " = " % ";"))
+                                                (str/join "\n")))))
+
+                           :js-symbol-names names-in-this-file
                            :properties properties
                            :source (.getCode source-file)
                            :source-map-json sm-json}]

src/main/shadow/build/targets/node_library.clj

@@ -1,17 +1,19 @@
 (ns shadow.build.targets.node-library
   (:refer-clojure :exclude (flush))
-  (:require [clojure.java.io :as io]
-            [clojure.string :as str]
-            [clojure.spec.alpha :as s]
-            [shadow.build.api :as cljs]
-            [shadow.build :as comp]
-            [shadow.build.targets.shared :as shared]
-            [shadow.build.config :as config]
-            [shadow.cljs.repl :as repl]
-            [shadow.build.node :as node]
-            [shadow.cljs.util :as util]
-            [shadow.build.data :as data]
-            [cljs.compiler :as cljs-comp]))
+  (:require
+    [clojure.java.io :as io]
+    [clojure.string :as str]
+    [clojure.spec.alpha :as s]
+    [cljs.compiler :as cljs-comp]
+    [shadow.cljs.repl :as repl]
+    [shadow.cljs.util :as util]
+    [shadow.build.api :as cljs]
+    [shadow.build :as comp]
+    [shadow.build.targets.shared :as shared]
+    [shadow.build.config :as config]
+    [shadow.build.node :as node]
+    [shadow.build.data :as data]
+    [shadow.build.output :as output]))
 
 (s/def ::exports
   (s/map-of
@@ -77,7 +79,7 @@
                     `(js/Object.defineProperty ~(-> k (name) (cljs-comp/munge))
                        (cljs.core/js-obj
                          "enumerable" true
-                         "get" (fn [] ~v)) )))
+                         "get" (fn [] ~v)))))
              )])
 
         requires
@@ -120,7 +122,7 @@
         ;; based on https://github.com/umdjs/umd/blob/master/templates/returnExports.js
         [prepend append]
         (-> wrapper-rc
-            (slurp )
+            (slurp)
             (str/split #"//CLJS-HERE"))
 
         prepend
@@ -180,7 +182,8 @@
         (shared/inject-node-repl config)
 
         (= :dev mode)
-        (shared/inject-preloads :main config)
+        (-> (shared/inject-preloads :main config)
+            (assoc ::output/eval-in-global-scope false))
         )))
 
 (defn flush [state mode config]

src/main/shadow/build/targets/node_script.clj

@@ -1,14 +1,16 @@
 (ns shadow.build.targets.node-script
   (:refer-clojure :exclude (flush))
-  (:require [cljs.compiler :as cljs-comp]
-            [clojure.spec.alpha :as s]
-            [shadow.cljs.repl :as repl]
-            [shadow.build.node :as node]
-            [shadow.build :as comp]
-            [shadow.build.targets.shared :as shared]
-            [shadow.build.config :as config]
-            [shadow.build.api :as cljs]
-            ))
+  (:require
+    [cljs.compiler :as cljs-comp]
+    [clojure.spec.alpha :as s]
+    [shadow.cljs.repl :as repl]
+    [shadow.build.node :as node]
+    [shadow.build :as comp]
+    [shadow.build.targets.shared :as shared]
+    [shadow.build.config :as config]
+    [shadow.build.api :as cljs]
+    [shadow.build.output :as output]
+    ))
 
 (s/def ::main shared/unquoted-qualified-symbol?)
 
@@ -41,7 +43,8 @@
         (shared/inject-node-repl config)
 
         (= :dev mode)
-        (shared/inject-preloads :main config)
+        (-> (shared/inject-preloads :main config)
+            (assoc ::output/eval-in-global-scope false))
         )))
 
 (defn check-main-exists! [{:keys [compiler-env node-config] :as state}]

src/main/shadow/build/targets/npm_module.clj

@@ -57,6 +57,9 @@
         (= :node runtime)
         (node/set-defaults)
 
+        (and (= :node runtime) (= :dev mode))
+        (assoc ::output/eval-in-global-scope false)
+
         (and (= :dev mode) (:worker-info state))
         (shared/merge-repl-defines config)
         )))