When reloading the dirstate, recompute ignore information if needed.

mercurial/dirstate.py

@@ -231,6 +231,16 b' class dirstate(object):'
         except IOError, err:
             if err.errno != errno.ENOENT: raise
 
+    def reload(self):
+        def mtime():
+            m = self.map and self.map.get('.hgignore')
+            return m and m[-1]
+
+        old_mtime = self.ignorefunc and mtime()
+        self.read()
+        if old_mtime != mtime():
+            self.ignorefunc = None
+
     def copy(self, source, dest):
         self.lazyread()
         self.markdirty()

mercurial/localrepo.py

@@ -596,7 +596,7 b' class localrepository(repo.repository):'
             self.ui.warn(_("no rollback information available\n"))
 
     def wreload(self):
-        self.dirstate.read()
+        self.dirstate.reload()
 
     def reload(self):
         self.changelog.load()