dirstate-map: factor out the change to _dirs and _alldirs on removing

This logic is complicated enough to deserves its own function. So it now does.

This will make it easier to reuse that logic in later changeset.

Differential Revision: https://phab.mercurial-scm.org/D11131

mercurial/dirstatemap.py

@@ -155,13 +155,15 b' class dirstatemap(object):'
         if old_entry is None and "_alldirs" in self.__dict__:
             self._alldirs.addpath(filename)
 
-    def _dirs_decr(self, filename, old_entry=None):
+    def _dirs_decr(self, filename, old_entry=None, remove_variant=False):
         """decremente the dirstate counter if applicable"""
         if old_entry is not None:
             if "_dirs" in self.__dict__ and not old_entry.removed:
                 self._dirs.delpath(filename)
-            if "_alldirs" in self.__dict__:
+            if "_alldirs" in self.__dict__ and not remove_variant:
                 self._alldirs.delpath(filename)
+        elif remove_variant and "_alldirs" in self.__dict__:
+            self._alldirs.addpath(filename)
         if "filefoldmap" in self.__dict__:
             normed = util.normcase(filename)
             self.filefoldmap.pop(normed, None)
@@ -241,14 +243,7 b' class dirstatemap(object):'
                     self.otherparentset.add(f)
         if entry is not None and not (entry.merged or entry.from_p2):
             self.copymap.pop(f, None)
-
-        if entry is not None and not entry.removed and "_dirs" in self.__dict__:
-            self._dirs.delpath(f)
-        if entry is None and "_alldirs" in self.__dict__:
-            self._alldirs.addpath(f)
-        if "filefoldmap" in self.__dict__:
-            normed = util.normcase(f)
-            self.filefoldmap.pop(normed, None)
+        self._dirs_decr(f, old_entry=entry, remove_variant=True)
         self._map[f] = DirstateItem(b'r', 0, size, 0)
         self.nonnormalset.add(f)