--- a/mercurial/commands.py	Tue Jun 23 13:56:53 2015 -0400
+++ b/mercurial/commands.py	Mon Jun 22 09:59:48 2015 -0700
@@ -21,7 +21,7 @@
 import dagparser, context, simplemerge, graphmod, copies
 import random
 import setdiscovery, treediscovery, dagutil, pvec, localrepo
-import phases, obsolete, exchange, bundle2
+import phases, obsolete, exchange, bundle2, repair
 import ui as uimod
 
 table = {}
@@ -2728,6 +2728,11 @@
     finally:
         wlock.release()
 
+@command('debugrebuildfncache', [], '')
+def debugrebuildfncache(ui, repo):
+    """rebuild the fncache file"""
+    repair.rebuildfncache(ui, repo)
+
 @command('debugrename',
     [('r', 'rev', '', _('revision to debug'), _('REV'))],
     _('[-r REV] FILE'))