[PATCH] obsolete: consider successors along with descendants when updating

[Levi Bard]

# HG changeset patch
# User Levi Bard <levi at unity3d.com>
# Date 1360532614 -3600
# Node ID 8d89080a98d69606ac264282e2ba3e33b056bcac
# Parent  013fcd112f13f31a35ea6a40d8cd1c6923cdaf20
obsolete: consider successors along with descendants when updating

Currently, if you pull --update a group of changesets that obsoletes
the current changeset, mercurial refuses to update because the pulled tip
is not a descendant. This change causes mercurial to consider successors
as well as descendants when determining whether to update.

diff -r 013fcd112f13 -r 8d89080a98d6 mercurial/merge.py
--- a/mercurial/merge.py	Sat Feb 09 11:00:42 2013 +0100
+++ b/mercurial/merge.py	Sun Feb 10 22:43:34 2013 +0100
@@ -7,6 +7,7 @@
 
 from node import nullid, nullrev, hex, bin
 from i18n import _
+from mercurial import obsolete
 import error, util, filemerge, copies, subrepo
 import errno, os, shutil
 
@@ -632,6 +633,9 @@
         elif not overwrite:
             if pa == p1 or pa == p2: # linear
                 pass # all good
+            elif repo.obsstore and \
+             node in obsolete.allsuccessors(repo.obsstore, [p1.node()]):
+                pa = p1 # allow updating to successors of obsolete nodes
             elif wc.dirty(missing=True):
                 raise util.Abort(_("crosses branches (merge branches or use"
                                    " --clean to discard changes)"))
diff -r 013fcd112f13 -r 8d89080a98d6 tests/test-pull-update.t
--- a/tests/test-pull-update.t	Sat Feb 09 11:00:42 2013 +0100
+++ b/tests/test-pull-update.t	Sun Feb 10 22:43:34 2013 +0100
@@ -1,3 +1,12 @@
+  $ cat << EOF >> $HGRCPATH
+  > [extensions]
+  > obs=$TESTTMP/obs.py
+  > EOF
+  $ cat > obs.py << EOF
+  > import mercurial.obsolete
+  > mercurial.obsolete._enabled = True
+  > EOF
+
   $ hg init t
   $ cd t
   $ echo 1 > foo
@@ -60,3 +69,64 @@
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
   $ cd ..
+
+Test no-argument update to a successor of an obsoleted changeset
+
+  $ hg init blah
+  $ cd blah
+  $ echo 1 > a
+  $ hg add a
+  $ hg commit -m0
+  $ echo 2 > a
+  $ hg commit -m1
+  $ cd ..
+  $ hg clone blah meh
+  updating to branch default
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ cd blah
+  $ echo 3 > a
+  $ hg commit --amend -m3
+  $ cd ../meh
+  $ hg pull --update ../blah
+  pulling from ../blah
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files (+1 heads)
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ cd ..
+
+Test refusal to update to a non-successor of an obsoleted changeset
+
+  $ rm -rf blah meh
+  $ hg init blah
+  $ cd blah
+  $ echo 1 > a
+  $ hg add a
+  $ hg commit -m0
+  $ echo 2 > a
+  $ hg commit -m1
+  $ cd ..
+  $ hg clone blah meh
+  updating to branch default
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ cd blah
+  $ echo 3 > a
+  $ hg commit --amend -m3
+  $ hg update 0
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ echo 4 > a
+  $ hg commit -m4
+  created new head
+  $ cd ../meh
+  $ hg pull --update ../blah
+  pulling from ../blah
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 2 changes to 1 files (+2 heads)
+  not updating: crosses branches (merge branches or update --check to force update)
+  $ cd ..
+