diff -r 1751d96d324f -r 7292a4618f46 mercurial/ui.py
--- a/mercurial/ui.py	Sun May 13 13:17:27 2012 +0200
+++ b/mercurial/ui.py	Sun May 13 13:17:31 2012 +0200
@@ -488,9 +488,9 @@
 
     def flush(self):
         try: self.fout.flush()
-        except: pass
+        except (IOError, ValueError): pass
         try: self.ferr.flush()
-        except: pass
+        except (IOError, ValueError): pass
 
     def interactive(self):
         '''is interactive input allowed?