localrepo: clear _filecache on rollback (issue3261)

Files are being replaced by rollback but the corresponding data in localrepo
isn't actually updated for things like bookmarks, phases, etc. Then when
rollback is done, the cache is updated thinking it has the most up-to-date
data, where in fact it is still pre-rollback.

We clear _filecache to force everything to be recreated.

mercurial/localrepo.py

@@ -1304,6 +1304,9 b' class localrepository(repo.repository):'
         # tag cache retrieval" case to work.
         self.invalidatecaches()
 
+        # Discard all cache entries to force reloading everything.
+        self._filecache.clear()
+
     def walk(self, match, node=None):
         '''
         walk recursively through the directory tree or a given

tests/test-commandserver.py

@@ -200,6 +200,16 b' def setphase(server):'
     os.system('hg phase -r . -p')
     runcommand(server, ['phase', '-r', '.'])
 
+def rollback(server):
+    readchannel(server)
+    runcommand(server, ['phase', '-r', '.', '-p'])
+    f = open('a', 'ab')
+    f.write('a\n')
+    f.close()
+    runcommand(server, ['commit', '-Am.'])
+    runcommand(server, ['rollback'])
+    runcommand(server, ['phase', '-r', '.'])
+
 if __name__ == '__main__':
     os.system('hg init')
 
@@ -219,3 +229,4 b" if __name__ == '__main__':"
     check(bookmarks)
     check(tagscache)
     check(setphase)
+    check(rollback)

tests/test-commandserver.py.out

@@ -134,3 +134,14 b' testing setphase:'
 3: draft
  runcommand phase -r .
 3: public
+no phases changed
+
+testing rollback:
+
+ runcommand phase -r . -p
+ runcommand commit -Am.
+ runcommand rollback
+repository tip rolled back to revision 3 (undo commit)
+working directory now based on revision 3
+ runcommand phase -r .
+3: public