rebase: turn rebaseskipobsolete on by default Consider the following use case. User has a set of commits he wants to rebase onto some destination. Some of the commits in the set are already rebased and their new versions are now among the ancestors of destination. Traditional rebase behavior would make the rebase and effectively try to apply older versions of these commits on top of newer versions, like this: a` --> b --> a` (where both 'a`' and 'a``' are rebased versions of 'a') This is not desired since 'b' might have made changes to 'a`' which can now result in merge conflicts. We can avoid these merge conflicts since we know that 'a``' is an older version of 'a`', so we don't even need to put it on top of 'b'. Rebaseskipobsolete allows us to do exactly that. Another undesired effect of a pure rebase is that now 'a`' and 'a``' are both successors to 'a' which is a divergence. We don't want that and not rebasing 'a' the second time allows to avoid it. This was not enabled by default initially because we wanted to have some more experience with it. After months of painless usages in multiple places, we are confident enough to turn it on my default.

--- a/hgext/rebase.py	Wed Mar 09 23:57:15 2016 +0900
+++ b/hgext/rebase.py	Wed Mar 09 08:08:27 2016 -0800
@@ -297,7 +297,8 @@
                     hint=_('use --keep to keep original changesets'))
 
             obsoletenotrebased = {}
-            if ui.configbool('experimental', 'rebaseskipobsolete'):
+            if ui.configbool('experimental', 'rebaseskipobsolete',
+                             default=True):
                 rebasesetrevs = set(rebaseset)
                 rebaseobsrevs = _filterobsoleterevs(repo, rebasesetrevs)
                 obsoletenotrebased = _computeobsoletenotrebased(repo,

--- a/tests/test-rebase-obsolete.t	Wed Mar 09 23:57:15 2016 +0900
+++ b/tests/test-rebase-obsolete.t	Wed Mar 09 08:08:27 2016 -0800
@@ -527,7 +527,7 @@
   $ hg commit -m J
   $ hg debugobsolete `hg log --rev . -T '{node}'`
 
-  $ hg rebase --rev .~1::. --dest 'max(desc(D))' --traceback
+  $ hg rebase --rev .~1::. --dest 'max(desc(D))' --traceback --config experimental.rebaseskipobsolete=off
   rebasing 9:4bde274eefcf "I"
   rebasing 13:06edfc82198f "J" (tip)
   $ hg log -G