CLJS-109: Compiler errors/warnings should be displayed when cljs namespace 'package' names start with an unacceptable javascript symbol

throw on invalid ns names

Author: swannodette

src/clj/cljs/analyzer.clj

@@ -1436,7 +1436,11 @@
       (warning :single-segment-namespace env {:name name}))
     (when (some js-reserved segments)
       (warning :munged-namespace env {:name name}))
-    (find-def-clash env name segments))
+    (find-def-clash env name segments)
+    (when (some (complement util/valid-js-id-start?) segments)
+      (throw (AssertionError.
+               (str "Namespace " name " has a segment starting with an invaild "
+                    "JavaScript identifier")))))
   (let [docstring (if (string? (first args)) (first args))
         mdocstr   (-> name meta :doc)
         args      (if docstring (next args) args)

src/clj/cljs/util.clj

@@ -126,6 +126,9 @@
       (when (= depth 0)
         (distinct (apply concat (vals @state)))))))
 
+(defn valid-js-id-start? [s]
+  (re-find #"(?U)^[\p{Alpha}_$]" s))
+
 (defn debug-prn
   [& args]
   (binding [*out* *err*]