dirstate: introduce a symbolic constant for the NONNORMAL marker

This is going to be clearer and easier to track than -1. Ultimately I would
like to get ride of this special value everywhere but in the lower level,
however we need to clarify the API first. This changeset is part of such
clarification.

Differential Revision: https://phab.mercurial-scm.org/D10927

mercurial/dirstate.py

@@ -51,6 +51,9 b' dirstatetuple = parsers.dirstatetuple'
 # a special value used internally for `size` if the file come from the other parent
 FROM_P2 = -2
 
+# a special value used internally for `size` if the file is modified/merged/added
+NONNORMAL = -1
+
 
 class repocache(filecache):
     """filecache for files in .hg/"""
@@ -488,9 +491,9 b' class dirstate(object):'
             # being removed, restore that state.
             entry = self._map.get(f)
             if entry is not None:
-                if entry[0] == b'r' and entry[2] in (-1, FROM_P2):
+                if entry[0] == b'r' and entry[2] in (NONNORMAL, FROM_P2):
                     source = self._map.copymap.get(f)
-                    if entry[2] == -1:
+                    if entry[2] == NONNORMAL:
                         self.merge(f)
                     elif entry[2] == FROM_P2:
                         self.otherparent(f)
@@ -499,7 +502,7 b' class dirstate(object):'
                     return
                 if entry[0] == b'm' or entry[0] == b'n' and entry[2] == FROM_P2:
                     return
-        self._addpath(f, b'n', 0, -1, -1)
+        self._addpath(f, b'n', 0, NONNORMAL, -1)
         self._map.copymap.pop(f, None)
 
     def otherparent(self, f):
@@ -517,7 +520,7 b' class dirstate(object):'
 
     def add(self, f):
         '''Mark a file added.'''
-        self._addpath(f, b'a', 0, -1, -1)
+        self._addpath(f, b'a', 0, NONNORMAL, -1)
         self._map.copymap.pop(f, None)
 
     def remove(self, f):
@@ -530,7 +533,7 b' class dirstate(object):'
             if entry is not None:
                 # backup the previous state
                 if entry[0] == b'm':  # merge
-                    size = -1
+                    size = NONNORMAL
                 elif entry[0] == b'n' and entry[2] == FROM_P2:  # other parent
                     size = FROM_P2
                     self._map.otherparentset.add(f)