commit bd19c0c019d401b4b9c0f6bc42f6eaf6038b4ddc
Author: Joel Pittet <joel@pittet.ca>
Date:   Fri Apr 5 20:45:47 2013 -0700

    rdf

diff --git a/core/modules/rdf/rdf.module b/core/modules/rdf/rdf.module
index 547075a..0f402d4 100644
--- a/core/modules/rdf/rdf.module
+++ b/core/modules/rdf/rdf.module
@@ -675,29 +675,22 @@ function rdf_preprocess_username(&$variables) {
     $variables['attributes']['about'] = url('user/' . $variables['uid']);
   }
 
-  $attributes = array();
   // The typeof attribute specifies the RDF type(s) of this resource. They
   // are defined in the 'rdftype' property of the user RDF mapping.
   if (!empty($rdf_mapping['rdftype'])) {
-    $attributes['typeof'] = $rdf_mapping['rdftype'];
+    $variables['attributes']['typeof'] = $rdf_mapping['rdftype'];
   }
   // Annotate the username in RDFa. A property attribute is used with an empty
   // datatype attribute to ensure the username is parsed as a plain literal
   // in RDFa 1.0 and 1.1.
   if (!empty($rdf_mapping['name'])) {
-    $attributes['property'] = $rdf_mapping['name']['predicates'];
-    $attributes['datatype'] = '';
+    $variables['attributes']['property'] = $rdf_mapping['name']['predicates'];
+    $variables['attributes']['datatype'] = '';
   }
   // Add the homepage RDFa markup if present.
   if (!empty($variables['homepage']) && !empty($rdf_mapping['homepage'])) {
-    $attributes['rel'] = $rdf_mapping['homepage']['predicates'];
-  }
-  // The remaining attributes can have multiple values listed, with whitespace
-  // separating the values in the RDFa attributes
-  // (see http://www.w3.org/TR/rdfa-syntax/#rdfa-attributes).
-  // Therefore, merge rather than override so as not to clobber values set by
-  // earlier preprocess functions.
-  $variables['attributes'] = NestedArray::mergeDeep($variables['attributes'], $attributes);
+    $variables['attributes']['rel'] = $rdf_mapping['homepage']['predicates'];
+  }
 }
 
 /**
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index a5dbdd8..253e7ce 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -744,6 +744,8 @@ function user_template_preprocess_default_variables_alter(&$variables) {
  * Modules that make any changes to variables like 'name' or 'extra' must ensure
  * that the final string is safe to include directly in the output by using
  * check_plain() or filter_xss().
+ *
+ * @see template_process_username()
  */
 function template_preprocess_username(&$variables) {
   $account = $variables['account'];