--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext3rd/evolve/evolvecmd.py	Fri Jan 19 14:42:46 2018 +0530
@@ -0,0 +1,43 @@
+# Copyright 2011 Peter Arrenbrecht <peter.arrenbrecht@gmail.com>
+#                Logilab SA        <contact@logilab.fr>
+#                Pierre-Yves David <pierre-yves.david@ens-lyon.org>
+#                Patrick Mezard <patrick@mezard.eu>
+#
+# This software may be used and distributed according to the terms of the
+# GNU General Public License version 2 or any later version.
+
+"""logic related to hg evolve command"""
+
+from mercurial import (
+    lock as lockmod,
+)
+
+from . import _solveunstable, _solvebumped, _solvedivergent
+
+def _solveone(ui, repo, ctx, dryrun, confirm, progresscb, category):
+    """Resolve the troubles affecting one revision
+
+    returns a tuple (bool, newnode) where,
+        bool: a boolean value indicating whether the instability was solved
+        newnode: if bool is True, then the newnode of the resultant commit
+                 formed. newnode can be node, when resolution led to no new
+                 commit. If bool is False, this is ''.
+    """
+    wlock = lock = tr = None
+    try:
+        wlock = repo.wlock()
+        lock = repo.lock()
+        tr = repo.transaction("evolve")
+        if 'orphan' == category:
+            result = _solveunstable(ui, repo, ctx, dryrun, confirm, progresscb)
+        elif 'phasedivergent' == category:
+            result = _solvebumped(ui, repo, ctx, dryrun, confirm, progresscb)
+        elif 'contentdivergent' == category:
+            result = _solvedivergent(ui, repo, ctx, dryrun, confirm,
+                                     progresscb)
+        else:
+            assert False, "unknown trouble category: %s" % (category)
+        tr.close()
+        return result
+    finally:
+        lockmod.release(tr, lock, wlock)