"empty" variable name does not work in a partial Fix #643

Author: jknack

handlebars/src/main/java/com/github/jknack/handlebars/internal/Partial.java

@@ -195,7 +195,11 @@ protected void merge(final Context context, final Writer writer)
 
       }
       context.data(Context.CALLEE, this);
-      Context ctx = Context.newPartialContext(context, this.scontext, hash(context));
+      Map<String, Object> hash = hash(context);
+      // HACK: hide/override local attribute with parent version (if any)
+      hash.put("size", context.get("size"));
+      hash.put("empty", context.get("empty"));
+      Context ctx = Context.newPartialContext(context, this.scontext, hash);
       template.apply(ctx, writer);
       context.data(Context.CALLEE, callee);
     } catch (IOException ex) {

handlebars/src/test/java/com/github/jknack/handlebars/issues/Issue539.java

@@ -4,8 +4,6 @@
 import com.github.jknack.handlebars.v4Test;
 import org.junit.Test;
 
-import java.io.IOException;
-
 public class Issue539 extends v4Test {
 
   @Override protected void configure(Handlebars handlebars)  {
@@ -52,4 +50,4 @@ public void inlinePartialsLeak() throws Exception {
             + "<br>\n"
             + "<br>");
   }
-}
+}

handlebars/src/test/java/com/github/jknack/handlebars/issues/Issue643.java

@@ -0,0 +1,17 @@
+package com.github.jknack.handlebars.issues;
+
+import com.github.jknack.handlebars.v4Test;
+import org.junit.Test;
+
+public class Issue643 extends v4Test {
+
+  @Test
+  public void shouldAllowES6LetOrConstLiterals() throws Exception {
+    shouldCompileTo("template: {{empty}} "
+            + "{{> partial}}",
+        $("partials", $("partial", "partial: {{empty}}"),
+            "data", $("empty", false)),
+        "template: true partial: true");
+  }
+
+}