dirstate: introduce a symbolic constant for the FROM_P2 marker

This is going to be clearer and easier to track than -2. 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/D10926

mercurial/dirstate.py

@@ -48,6 +48,10 b' filecache = scmutil.filecache'
 dirstatetuple = parsers.dirstatetuple
 
 
+# a special value used internally for `size` if the file come from the other parent
+FROM_P2 = -2
+
+
 class repocache(filecache):
     """filecache for files in .hg/"""
 
@@ -371,7 +375,7 b' class dirstate(object):'
                         copies[f] = source
                     self.normallookup(f)
                 # Also fix up otherparent markers
-                elif s[0] == b'n' and s[2] == -2:
+                elif s[0] == b'n' and s[2] == FROM_P2:
                     source = self._map.copymap.get(f)
                     if source:
                         copies[f] = source
@@ -484,16 +488,16 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, -2):
+                if entry[0] == b'r' and entry[2] in (-1, FROM_P2):
                     source = self._map.copymap.get(f)
                     if entry[2] == -1:
                         self.merge(f)
-                    elif entry[2] == -2:
+                    elif entry[2] == FROM_P2:
                         self.otherparent(f)
                     if source:
                         self.copy(source, f)
                     return
-                if entry[0] == b'm' or entry[0] == b'n' and entry[2] == -2:
+                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._map.copymap.pop(f, None)
@@ -505,10 +509,10 b' class dirstate(object):'
             raise error.Abort(msg)
         if f in self and self[f] == b'n':
             # merge-like
-            self._addpath(f, b'm', 0, -2, -1)
+            self._addpath(f, b'm', 0, FROM_P2, -1)
         else:
             # add-like
-            self._addpath(f, b'n', 0, -2, -1)
+            self._addpath(f, b'n', 0, FROM_P2, -1)
         self._map.copymap.pop(f, None)
 
     def add(self, f):
@@ -527,8 +531,8 b' class dirstate(object):'
                 # backup the previous state
                 if entry[0] == b'm':  # merge
                     size = -1
-                elif entry[0] == b'n' and entry[2] == -2:  # other parent
-                    size = -2
+                elif entry[0] == b'n' and entry[2] == FROM_P2:  # other parent
+                    size = FROM_P2
                     self._map.otherparentset.add(f)
         self._updatedfiles.add(f)
         self._map.removefile(f, oldstate, size)
@@ -1302,7 +1306,7 b' class dirstate(object):'
                         (size != st.st_size and size != st.st_size & _rangemask)
                         or ((mode ^ st.st_mode) & 0o100 and checkexec)
                     )
-                    or size == -2  # other parent
+                    or size == FROM_P2  # other parent
                     or fn in copymap
                 ):
                     if stat.S_ISLNK(st.st_mode) and size != st.st_size:
@@ -1532,7 +1536,7 b' class dirstatemap(object):'
         self._map[f] = dirstatetuple(state, mode, size, mtime)
         if state != b'n' or mtime == -1:
             self.nonnormalset.add(f)
-        if size == -2:
+        if size == FROM_P2:
             self.otherparentset.add(f)
 
     def removefile(self, f, oldstate, size):
@@ -1587,7 +1591,7 b' class dirstatemap(object):'
             for fname, e in pycompat.iteritems(self._map):
                 if e[0] != b'n' or e[3] == -1:
                     nonnorm.add(fname)
-                if e[0] == b'n' and e[2] == -2:
+                if e[0] == b'n' and e[2] == FROM_P2:
                     otherparent.add(fname)
             return nonnorm, otherparent