store: assert the fncache have been loaded if dirty
This should catch fncache corruption as the one that existed in
`perffncachewrite`.
--- a/mercurial/store.py Sat Jul 14 02:09:47 2018 +0200
+++ b/mercurial/store.py Sat Jul 14 02:10:43 2018 +0200
@@ -449,6 +449,7 @@
def write(self, tr):
if self._dirty:
+ assert self.entries is not None
tr.addbackup('fncache')
fp = self.vfs('fncache', mode='wb', atomictemp=True)
if self.entries: