dirstate: add a `set_possibly_dirty` method

This method will be able to replace some usage of `normallookup` in the future.

Differential Revision: https://phab.mercurial-scm.org/D11162

mercurial/dirstate.py

@@ -506,6 +506,13 b' class dirstate(object):'
         self._updatedfiles.add(filename)
         self._normal(filename, parentfiledata=parentfiledata)
 
+    @requires_no_parents_change
+    def set_possibly_dirty(self, filename):
+        """record that the current state of the file on disk is unknown"""
+        self._dirty = True
+        self._updatedfiles.add(filename)
+        self._map.set_possibly_dirty(filename)
+
     @requires_parents_change
     def update_file_p1(
         self,

mercurial/dirstatemap.py

@@ -168,6 +168,10 b' class dirstatemap(object):'
             normed = util.normcase(filename)
             self.filefoldmap.pop(normed, None)
 
+    def set_possibly_dirty(self, filename):
+        """record that the current state of the file on disk is unknown"""
+        self[filename].set_possibly_dirty()
+
     def addfile(
         self,
         f,
@@ -907,6 +911,12 b' if rustmod is not None:'
                 f[normcase(name)] = name
             return f
 
+        def set_possibly_dirty(self, filename):
+            """record that the current state of the file on disk is unknown"""
+            entry = self[filename]
+            entry.set_possibly_dirty()
+            self._rustmap.set_v1(filename, entry)
+
         def __setitem__(self, key, value):
             assert isinstance(value, DirstateItem)
             self._rustmap.set_v1(key, value)