Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.1001
diff -u -9 -p -r1.1001 common.inc
--- includes/common.inc	30 Sep 2009 13:09:29 -0000	1.1001
+++ includes/common.inc	30 Sep 2009 16:18:20 -0000
@@ -514,20 +514,23 @@ function drupal_parse_url($url) {
       parse_str($query_parts[0], $options['query']);
       // Take over the fragment, if there is any.
       if (isset($query_parts[1])) {
         $options['fragment'] = $query_parts[1];
       }
     }
   }
   // Internal URLs.
   else {
-    $parts = parse_url($url);
-    $options['path'] = $parts['path'];
+    // parse_url() does not support relative URLs, so make it absolute. E.g. the
+    // relative URL "foo/bar:1" isn't properly parsed.
+    $parts = parse_url('http://example.com/' . $url);
+    // Strip the leading slash that was just added.
+    $options['path'] = substr($parts['path'], 1);
     if (isset($parts['query'])) {
       parse_str($parts['query'], $options['query']);
     }
     if (isset($parts['fragment'])) {
       $options['fragment'] = $parts['fragment'];
     }
   }
 
   return $options;
Index: modules/simpletest/tests/common.test
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/common.test,v
retrieving revision 1.75
diff -u -9 -p -r1.75 common.test
--- modules/simpletest/tests/common.test	29 Sep 2009 15:31:15 -0000	1.75
+++ modules/simpletest/tests/common.test	30 Sep 2009 16:18:22 -0000
@@ -88,18 +88,27 @@ class CommonURLUnitTest extends DrupalUn
     // Relative URL.
     $url = 'foo/bar?foo=bar&bar=baz&baz#foo';
     $result = array(
       'path' => 'foo/bar',
       'query' => array('foo' => 'bar', 'bar' => 'baz', 'baz' => ''),
       'fragment' => 'foo',
     );
     $this->assertEqual(drupal_parse_url($url), $result, t('Relative URL parsed correctly.'));
 
+    // Relative URL that is known to confuse parse_url().
+    $url = 'foo/bar:1';
+    $result = array(
+      'path' => 'foo/bar:1',
+      'query' => array(),
+      'fragment' => '',
+    );
+    $this->assertEqual(drupal_parse_url($url), $result, t('Relative URL parsed correctly.'));
+
     // Absolute URL.
     $url = '/foo/bar?foo=bar&bar=baz&baz#foo';
     $result = array(
       'path' => '/foo/bar',
       'query' => array('foo' => 'bar', 'bar' => 'baz', 'baz' => ''),
       'fragment' => 'foo',
     );
     $this->assertEqual(drupal_parse_url($url), $result, t('Absolute URL parsed correctly.'));