dirstate: add an explicit `from_p2` parameter to `_addpath`

This lets says what we mean instead of using magic value. The lower level can
then decide how to express that.

Differential Revision: https://phab.mercurial-scm.org/D10931

mercurial/dirstate.py

@@ -438,7 +438,15 b' class dirstate(object):'
     def copies(self):
         return self._map.copymap
 
-    def _addpath(self, f, state, mode, size=NONNORMAL, mtime=AMBIGUOUS_TIME):
+    def _addpath(
+        self,
+        f,
+        state,
+        mode,
+        size=NONNORMAL,
+        mtime=AMBIGUOUS_TIME,
+        from_p2=False,
+    ):
         oldstate = self[f]
         if state == b'a' or oldstate == b'r':
             scmutil.checkfilename(f)
@@ -455,7 +463,12 b' class dirstate(object):'
                     msg = _(b'file %r in dirstate clashes with %r')
                     msg %= (pycompat.bytestr(d), pycompat.bytestr(f))
                     raise error.Abort(msg)
-        if size != NONNORMAL and size != FROM_P2:
+        if from_p2:
+            size = FROM_P2
+            mtime = AMBIGUOUS_TIME
+        else:
+            assert size != FROM_P2
+            if size != NONNORMAL:
             size = size & _rangemask
         if mtime != AMBIGUOUS_TIME:
             mtime = mtime & _rangemask
@@ -519,10 +532,10 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, FROM_P2)
+            self._addpath(f, b'm', 0, from_p2=True)
         else:
             # add-like
-            self._addpath(f, b'n', 0, FROM_P2)
+            self._addpath(f, b'n', 0, from_p2=True)
         self._map.copymap.pop(f, None)
 
     def add(self, f):