prototype: Fix template evaluation with empty replacements. Closes #9692.

CHANGELOG

@@ -1,9 +1,13 @@
-*1.6.0_rc1* (October 16, 2007)
+*SVN*
+
+* Fix template evaluation with empty replacements.  Closes #9692.  [Ryan McGeary]
 
 * Hash#toTemplateReplacements is an alias for Hash#toObject so you can once again pass hashes to Template#evaluate and String#interpolate.  [sam]
 
 * Fix Event#is(Left|Middle|Right)Click in IE.  Closes #7520 (again).  [Mislav Marohnić]
 
+*1.6.0_rc1* (October 16, 2007)
+
 * Ensure Event.* generic methods work in IE, even when the event is not extended. [Viktor Kojouharov, Andrew Dupont]
 
 * Don't translate "keypress" events into "keydown" events.  [sam]

src/string.js

@@ -246,7 +246,7 @@ var Template = Class.create({
       
       var ctx = object, expr = match[3];
       var pattern = /^([^.[]+|\[((?:.*?[^\\])?)\])(\.|\[|$)/, match = pattern.exec(expr);
-      if (match == null) return '';
+      if (match == null) return before;
 
       while (match != null) {
         var comp = match[1].startsWith('[') ? match[2].gsub('\\\\]', ']') : match[1];

test/unit/string.html

@@ -305,6 +305,15 @@
         template.evaluate({}));
     }},
 
+    testTemplateEvaluationWithEmptyReplacement: function() {with(this) {
+      var template = new Template('##{}');
+      assertEqual('#', template.evaluate({}));
+      assertEqual('#', template.evaluate({foo: 'bar'}));
+
+      template = new Template('#{}');
+      assertEqual('', template.evaluate({}));
+    }},
+
     testTemplateEvaluationWithFalses: function() {with(this) {
       var source = '<tr><td>#{zero}</td><td>#{false_}</td><td>#{undef}</td><td>#{null_}</td><td>#{empty}</td></tr>';
       var falses = {zero:0, false_:false, undef:undefined, null_:null, empty:""};