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

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/D11130

mercurial/dirstatemap.py

@@ -155,6 +155,17 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):
+        """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__:
+                self._alldirs.delpath(filename)
+        if "filefoldmap" in self.__dict__:
+            normed = util.normcase(filename)
+            self.filefoldmap.pop(normed, None)
+
     def addfile(
         self,
         f,
@@ -247,21 +258,9 b' class dirstatemap(object):'
         previously recorded.
         """
         old_entry = self._map.pop(f, None)
-        exists = False
-        oldstate = b'?'
-        if old_entry is not None:
-            exists = True
-            oldstate = old_entry.state
-        if exists:
-            if oldstate != b"r" and "_dirs" in self.__dict__:
-                self._dirs.delpath(f)
-            if "_alldirs" in self.__dict__:
-                self._alldirs.delpath(f)
-        if "filefoldmap" in self.__dict__:
-            normed = util.normcase(f)
-            self.filefoldmap.pop(normed, None)
+        self._dirs_decr(f, old_entry=old_entry)
         self.nonnormalset.discard(f)
-        return exists
+        return old_entry is not None
 
     def clearambiguoustimes(self, files, now):
         for f in files: