pull: fix crash when pulling changeset that get hidden locally (issue3788)

When you have obsolescence marker that apply to a pulled changesets, the added
changeset is immediately filtered. Then the list of added changeset needs to be
build against and unfiltered repo.

mercurial/localrepo.py

@@ -1688,10 +1688,14 b' class localrepository(object):'
                                            "changegroupsubset."))
                 else:
                     cg = remote.changegroupsubset(fetch, heads, 'pull')
-                clstart = len(self.changelog)
+                # we use unfiltered changelog here because hidden revision must
+                # be taken in account for phase synchronization. They may
+                # becomes public and becomes visible again.
+                cl = self.unfiltered().changelog
+                clstart = len(cl)
                 result = self.addchangegroup(cg, 'pull', remote.url())
-                clend = len(self.changelog)
-                added = [self.changelog.node(r) for r in xrange(clstart, clend)]
+                clend = len(cl)
+                added = [cl.node(r) for r in xrange(clstart, clend)]
 
             # compute target subset
             if heads is None:

tests/test-obsolete-changeset-exchange.t

@@ -53,3 +53,23 b' Push it. The bundle should not refer to '
   crosschecking files in changesets and manifests
   checking files
   2 files, 2 changesets, 2 total revisions
+
+Adding a changeset going extinct locally
+------------------------------------------
+
+Pull a changeset that will immediatly goes extinct (because you already have a
+marker to obsolete him)
+(test resolution of issue3788)
+
+  $ hg phase --draft --force f89bcc95eba5
+  $ hg phase -R ../other --draft --force f89bcc95eba5
+  $ hg commit --amend -m "A''"
+  $ hg --hidden --config extensions.mq= strip  --no-backup f89bcc95eba5
+  $ hg pull ../other
+  pulling from ../other
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 0 changes to 1 files (+1 heads)
+  (run 'hg heads' to see heads, 'hg merge' to merge)