upgrade: fix DELTAREUSEFULLADD implementation in revlog.clone

If we do a full addition, we need to start from the full text.

Differential Revision: https://phab.mercurial-scm.org/D6901

mercurial/revlog.py

@@ -2437,7 +2437,14 class revlog(object):
             # the revlog chunk is a delta.
             cachedelta = None
             rawtext = None
-            if (deltareuse != self.DELTAREUSEFULLADD and destrevlog._lazydelta):
+            if deltareuse == self.DELTAREUSEFULLADD:
+                text = self.revision(rev)
+                destrevlog.addrevision(text, tr, linkrev, p1, p2,
+                                       cachedelta=cachedelta,
+                                       node=node, flags=flags,
+                                       deltacomputer=deltacomputer)
+            else:
+                if destrevlog._lazydelta:
                 dp = self.deltaparent(rev)
                 if dp != nullrev:
                     cachedelta = (dp, bytes(self._chunk(rev)))
@@ -2445,13 +2452,6 class revlog(object):
             if not cachedelta:
                 rawtext = self.rawdata(rev)
 
-
-            if deltareuse == self.DELTAREUSEFULLADD:
-                destrevlog.addrevision(rawtext, tr, linkrev, p1, p2,
-                                       cachedelta=cachedelta,
-                                       node=node, flags=flags,
-                                       deltacomputer=deltacomputer)
-            else:
                 ifh = destrevlog.opener(destrevlog.indexfile, 'a+',
                                         checkambig=False)
                 dfh = None