diff --git a/mercurial/subrepo.py b/mercurial/subrepo.py
--- a/mercurial/subrepo.py
+++ b/mercurial/subrepo.py
@@ -499,13 +499,23 @@ class svnsubrepo(abstractsubrepo):
             raise util.Abort(stderr)
         return stdout
 
-    def _wcrev(self):
+    def _wcrevs(self):
+        # Get the working directory revision as well as the last
+        # commit revision so we can compare the subrepo state with
+        # both. We used to store the working directory one.
         output = self._svncommand(['info', '--xml'])
         doc = xml.dom.minidom.parseString(output)
         entries = doc.getElementsByTagName('entry')
-        if not entries:
-            return '0'
-        return str(entries[0].getAttribute('revision')) or '0'
+        lastrev, rev = '0', '0'
+        if entries:
+            rev = str(entries[0].getAttribute('revision')) or '0'
+            commits = entries[0].getElementsByTagName('commit')
+            if commits:
+                lastrev = str(commits[0].getAttribute('revision')) or '0'
+        return (lastrev, rev)
+
+    def _wcrev(self):
+        return self._wcrevs()[0]
 
     def _wcchanged(self):
         """Return (changes, extchanges) where changes is True
@@ -534,7 +544,7 @@ class svnsubrepo(abstractsubrepo):
         return bool(changes), False
 
     def dirty(self):
-        if self._wcrev() == self._state[1] and not self._wcchanged()[0]:
+        if self._state[1] in self._wcrevs() and not self._wcchanged()[0]:
             return False
         return True
 
diff --git a/tests/test-subrepo-svn.t b/tests/test-subrepo-svn.t
--- a/tests/test-subrepo-svn.t
+++ b/tests/test-subrepo-svn.t
@@ -123,6 +123,25 @@ change file in svn and hg, commit
    source   file://*/svn-repo/src (glob)
    revision 2
 
+add an unrelated revision in svn and update the subrepo to without
+bringing any changes.
+
+  $ svn mkdir --parents "$SVNREPO/unrelated" -m 'create unrelated'
+  
+  Committed revision 4.
+  $ svn up s
+  
+  Fetching external item into 's/externals'
+  External at revision 1.
+  
+  At revision 4.
+  $ hg sum
+  parent: 2:* tip (glob)
+   Message!
+  branch: default
+  commit: (clean)
+  update: (current)
+
   $ echo a > s/a
 
 should be empty despite change to s/a
@@ -139,14 +158,14 @@ add a commit from svn
   A    externals/other
   Updated external to revision 1.
   
-  Updated to revision 3.
+  Updated to revision 4.
   $ echo xyz >> alpha
   $ svn propset svn:mime-type 'text/xml' alpha
   property 'svn:mime-type' set on 'alpha'
   $ svn ci -m 'amend a from svn'
   Sending        src/alpha
   Transmitting file data .
-  Committed revision 4.
+  Committed revision 5.
   $ cd ../../sub/t
 
 this commit from hg will fail