obsolete: add revset and test for divergent changesets

This changesets add a new `divergent()` revset similar to `unstable()` and
`bumped()` one. Introducting this revset allows actuall test of the divergent
detection.

mercurial/revset.py

@@ -646,6 +646,15 b' def destination(repo, subset, x):'
 
     return [r for r in subset if r in dests]
 
+def divergent(repo, subset, x):
+    """``divergent()``
+    Final successors of changesets with an alternative set of final successors.
+    """
+    # i18n: "divergent" is a keyword
+    getargs(x, 0, 0, _("divergent takes no arguments"))
+    divergent = obsmod.getrevs(repo, 'divergent')
+    return [r for r in subset if r in divergent]
+
 def draft(repo, subset, x):
     """``draft()``
     Changeset in draft phase."""
@@ -1541,6 +1550,7 b' symbols = {'
     "descendants": descendants,
     "_firstdescendants": _firstdescendants,
     "destination": destination,
+    "divergent": divergent,
     "draft": draft,
     "extinct": extinct,
     "extra": extra,

tests/test-obsolete-divergent.t

@@ -81,6 +81,9 b' A_1 have two direct and divergent succes'
       82623d38b9ba
   392fd25390da
       392fd25390da
+  $ hg log -r 'divergent()'
+  2:82623d38b9ba A_1
+  3:392fd25390da A_2
   $ cd ..
 
 
@@ -116,6 +119,9 b' indirect divergence with known changeset'
       01f36c5a8fda
   01f36c5a8fda
       01f36c5a8fda
+  $ hg log -r 'divergent()'
+  2:82623d38b9ba A_1
+  4:01f36c5a8fda A_3
   $ cd ..
 
 
@@ -145,6 +151,9 b' indirect divergence with known changeset'
       82623d38b9ba
   392fd25390da
       392fd25390da
+  $ hg log -r 'divergent()'
+  2:82623d38b9ba A_1
+  3:392fd25390da A_2
   $ cd ..
 
 do not take unknown node in account if they are final
@@ -195,6 +204,7 b' divergence that converge again is not di'
       01f36c5a8fda
   01f36c5a8fda
       01f36c5a8fda
+  $ hg log -r 'divergent()'
   $ cd ..
 
 split is not divergences
@@ -220,6 +230,7 b' split is not divergences'
       82623d38b9ba
   392fd25390da
       392fd25390da
+  $ hg log -r 'divergent()'
 
 Even when subsequente rewriting happen
 
@@ -266,6 +277,7 b' Even when subsequente rewriting happen'
       e442cfc57690
   e442cfc57690
       e442cfc57690
+  $ hg log -r 'divergent()'
 
 Check more complexe obsolescence graft (with divergence)
 
@@ -334,6 +346,11 b' Check more complexe obsolescence graft ('
       14608b260df8
   bed64f5d2f5a
       bed64f5d2f5a
+  $ hg log -r 'divergent()'
+  4:01f36c5a8fda A_3
+  8:7ae126973a96 A_7
+  9:14608b260df8 A_8
+  10:bed64f5d2f5a A_9
 
 fix the divergence
 
@@ -393,6 +410,7 b' fix the divergence'
       a139f71be9da
   a139f71be9da
       a139f71be9da
+  $ hg log -r 'divergent()'
 
   $ cd ..