dirstate: move parent state handling in the dirstatemap

This involves dirstatemap data mostly. Moving this one level down will remove
the needs for the dirstatemap to expose some of its internals.

This will help us to simplify more code further.

Differential Revision: https://phab.mercurial-scm.org/D11505

mercurial/dirstate.py

@@ -381,39 +381,10 b' class dirstate(object):'
         oldp2 = self._pl[1]
         if self._origpl is None:
             self._origpl = self._pl
-        self._map.setparents(p1, p2)
-        copies = {}
         nullid = self._nodeconstants.nullid
-        if oldp2 != nullid and p2 == nullid:
-            candidatefiles = self._map.non_normal_or_other_parent_paths()
-
-            for f in candidatefiles:
-                s = self._map.get(f)
-                if s is None:
-                    continue
-
-                # Discard "merged" markers when moving away from a merge state
-                if s.merged:
-                    source = self._map.copymap.get(f)
-                    if source:
-                        copies[f] = source
-                    self._map.reset_state(
-                        f,
-                        wc_tracked=True,
-                        p1_tracked=True,
-                        possibly_dirty=True,
-                    )
-                # Also fix up otherparent markers
-                elif s.from_p2:
-                    source = self._map.copymap.get(f)
-                    if source:
-                        copies[f] = source
-                    self._map.reset_state(
-                        f,
-                        p1_tracked=False,
-                        wc_tracked=True,
-                    )
-        return copies
+        # True if we need to fold p2 related state back to a linear case
+        fold_p2 = oldp2 != nullid and p2 == nullid
+        return self._map.setparents(p1, p2, fold_p2=fold_p2)
 
     def setbranch(self, branch):
         self.__class__._branch.set(self, encoding.fromlocal(branch))

mercurial/dirstatemap.py

@@ -428,9 +428,40 b' class dirstatemap(object):'
 
         return self._parents
 
-    def setparents(self, p1, p2):
+    def setparents(self, p1, p2, fold_p2=False):
         self._parents = (p1, p2)
         self._dirtyparents = True
+        copies = {}
+        if fold_p2:
+            candidatefiles = self.non_normal_or_other_parent_paths()
+
+            for f in candidatefiles:
+                s = self.get(f)
+                if s is None:
+                    continue
+
+                # Discard "merged" markers when moving away from a merge state
+                if s.merged:
+                    source = self.copymap.get(f)
+                    if source:
+                        copies[f] = source
+                    self.reset_state(
+                        f,
+                        wc_tracked=True,
+                        p1_tracked=True,
+                        possibly_dirty=True,
+                    )
+                # Also fix up otherparent markers
+                elif s.from_p2:
+                    source = self.copymap.get(f)
+                    if source:
+                        copies[f] = source
+                    self.reset_state(
+                        f,
+                        p1_tracked=False,
+                        wc_tracked=True,
+                    )
+        return copies
 
     def read(self):
         # ignore HG_PENDING because identity is used only for writing
@@ -769,9 +800,40 b' if rustmod is not None:'
                 # File doesn't exist, so the current state is empty
                 return b''
 
-        def setparents(self, p1, p2):
+        def setparents(self, p1, p2, fold_p2=False):
             self._parents = (p1, p2)
             self._dirtyparents = True
+            copies = {}
+            if fold_p2:
+                candidatefiles = self.non_normal_or_other_parent_paths()
+
+                for f in candidatefiles:
+                    s = self.get(f)
+                    if s is None:
+                        continue
+
+                    # Discard "merged" markers when moving away from a merge state
+                    if s.merged:
+                        source = self.copymap.get(f)
+                        if source:
+                            copies[f] = source
+                        self.reset_state(
+                            f,
+                            wc_tracked=True,
+                            p1_tracked=True,
+                            possibly_dirty=True,
+                        )
+                    # Also fix up otherparent markers
+                    elif s.from_p2:
+                        source = self.copymap.get(f)
+                        if source:
+                            copies[f] = source
+                        self.reset_state(
+                            f,
+                            p1_tracked=False,
+                            wc_tracked=True,
+                        )
+            return copies
 
         def parents(self):
             if not self._parents: