ClojureBindings: avoid warnings in map population

Calling the Var.intern method dumps a warning to stderr
when an already-existing variable is requested.

I did not study the code extremely carefully, but it seems like
internally, Clojure discovers an existing variable, decides to overwrite
it with a different variable object for some reason, and then warns that
it has done so. But this phenomenon apparently occurs only once.

In any case, the workaround is simply to avoid calling Var.intern,
in favor of Namespace.getMappings().valAt(Symbol) directly.

Author: ctrueden

src/main/java/org/scijava/plugins/scripting/clojure/ClojureBindings.java

@@ -172,9 +172,16 @@ private static Map<String, Object> map() {
 		for (final Object el : ns.getMappings()) {
 			final MapEntry entry = (MapEntry) el;
 			final Symbol key = (Symbol) entry.key();
-			final Object value = Var.intern(ns, key).get();
-			if (value instanceof Var.Unbound) continue; // skip weird variables
-			map.put(key.getName(), value);
+			// NB: Unfortunately, we cannot simply write:
+			//   final Object value = Var.intern(ns, key).get();
+			// because it issues a warning for already-existing variables.
+			// So instead, we replicate some of its internals here.
+			final Object valAt = ns.getMappings().valAt(key);
+			final Var valVar = valAt instanceof Var ? ((Var) valAt) : null;
+			if (valVar == null) continue; // skip non-variables
+			if (valVar.ns != ns) continue; // skip non-user vars
+			if (!valVar.isBound()) continue; // skip unbound vars
+			map.put(key.getName(), valVar.get());
 		}
 
 		return map;