Fix brianc#10: prevent leaking and mutation of column state

Justin Reidy · Justin Reidy · commit cda60da73a8b · 2012-12-18T14:07:50.000-08:00
diff --git a/lib/column.js b/lib/column.js
@@ -34,6 +34,14 @@ var unaryMethod = function(name, operator) {
   }
 }
 
+var contextify = function(base) {
+  var context = Object.create(Column.prototype);
+  Object.keys(base).forEach(function (key) {
+    context[key] = base[key];
+  })
+  return context;
+}
+
 Column.prototype.value = function(value) {
   this._value = value;
   return this;
@@ -45,12 +53,13 @@ Column.prototype.getValue = function() {
 
 Column.prototype.toNode = function() {
   //creates a query node from this column
-  return new ColumnNode(this);
+  return new ColumnNode(contextify(this));
 }
 
 Column.prototype.as = function(alias) {
-  this.alias = alias;
-  return new ColumnNode(this);
+  var context = contextify(this);
+  context.alias = alias;
+  return new ColumnNode(context);
 }
 
 binaryMethod('equals', '=');
diff --git a/test/dialect-tests.js b/test/dialect-tests.js
@@ -102,6 +102,12 @@ test({
   pg    : 'SELECT "user"."name" as "user name" FROM "user" WHERE ("user"."name" = $1)'
 });
 
+//Fix #10: prevent column state mutation
+test({
+  query : user.select(user.name).from(user).where(user.name.equals('brian')),
+  pg    : 'SELECT "user"."name" FROM "user" WHERE ("user"."name" = $1)'
+});
+
 var u = user.as('u');
 test({
   query : u.select(u.name).from(u),
