manifest: make treemanifestctx store the repo stable

manifest: make treemanifestctx store the repo

Same as in the last commit, the old treemanifestctx stored a reference to the
revlog.  If the inmemory revlog became invalid, the ctx now held an old copy and
would be incorrect. To fix this, we need the ctx to go through the manifestlog
for each access.

This is the same pattern that changectx already uses (it stores the repo, and
accesses commit data through self._repo.changelog).

--- a/mercurial/manifest.py	Tue Oct 18 17:44:26 2016 -0700
+++ b/mercurial/manifest.py	Tue Oct 18 17:44:42 2016 -0700
@@ -1274,7 +1274,7 @@
                 return cachemf
 
         if self._treeinmem:
-            m = treemanifestctx(self._revlog, '', node)
+            m = treemanifestctx(self._repo, '', node)
         else:
             m = manifestctx(self._repo, node)
         if node != revlog.nullid:
@@ -1344,9 +1344,8 @@
         return manifestdict(d)
 
 class treemanifestctx(object):
-    def __init__(self, revlog, dir, node):
-        revlog = revlog.dirlog(dir)
-        self._revlog = revlog
+    def __init__(self, repo, dir, node):
+        self._repo = repo
         self._dir = dir
         self._data = None
 
@@ -1359,23 +1358,27 @@
         #rev = revlog.rev(node)
         #self.linkrev = revlog.linkrev(rev)
 
+    def _revlog(self):
+        return self._repo.manifestlog._revlog.dirlog(self._dir)
+
     def read(self):
         if not self._data:
+            rl = self._revlog()
             if self._node == revlog.nullid:
                 self._data = treemanifest()
-            elif self._revlog._treeondisk:
+            elif rl._treeondisk:
                 m = treemanifest(dir=self._dir)
                 def gettext():
-                    return self._revlog.revision(self._node)
+                    return rl.revision(self._node)
                 def readsubtree(dir, subm):
-                    return treemanifestctx(self._revlog, dir, subm).read()
+                    return treemanifestctx(self._repo, dir, subm).read()
                 m.read(gettext, readsubtree)
                 m.setnode(self._node)
                 self._data = m
             else:
-                text = self._revlog.revision(self._node)
+                text = revlog.revision(self._node)
                 arraytext = array.array('c', text)
-                self._revlog.fulltextcache[self._node] = arraytext
+                rl.fulltextcache[self._node] = arraytext
                 self._data = treemanifest(dir=self._dir, text=text)
 
         return self._data
@@ -1385,9 +1388,9 @@
 
     def readdelta(self):
         # Need to perform a slow delta
-        revlog = self._revlog
+        revlog = self._revlog()
         r0 = revlog.deltaparent(revlog.rev(self._node))
-        m0 = treemanifestctx(revlog, self._dir, revlog.node(r0)).read()
+        m0 = treemanifestctx(self._repo, self._dir, revlog.node(r0)).read()
         m1 = self.read()
         md = treemanifest(dir=self._dir)
         for f, ((n0, fl0), (n1, fl1)) in m0.diff(m1).iteritems():
@@ -1398,7 +1401,7 @@
         return md
 
     def readfast(self):
-        rl = self._revlog
+        rl = self._revlog()
         r = rl.rev(self._node)
         deltaparent = rl.deltaparent(r)
         if deltaparent != revlog.nullrev and deltaparent in rl.parentrevs(r):