# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@fb.com>
# Date 1444874409 -3600
# Node ID 8e6649616699459223c41631a5897c36a1d35201
# Parent  bde739aced83f5b209e974e6878a69a0e349cfad
destupdate: have a generic and extensible way to run each step

We want extension to be able to easily override or add new way to select the
default update destination. We use the same list + dict approach as in other
parts of the code.

diff -r bde739aced83 -r 8e6649616699 mercurial/destutil.py
--- a/mercurial/destutil.py	Thu Oct 15 02:33:09 2015 +0100
+++ b/mercurial/destutil.py	Thu Oct 15 03:00:09 2015 +0100
@@ -100,6 +100,15 @@
             raise error.Abort(_("branch %s not found") % wc.branch())
     return node, movemark, None
 
+# order in which each step should be evalutated
+# steps are run until one finds a destination
+destupdatesteps = ['evolution', 'bookmark', 'branch']
+# mapping to ease extension overriding steps.
+destupdatestepmap = {'evolution': _destupdateobs,
+                     'bookmark': _destupdatebook,
+                     'branch': _destupdatebranch,
+                     }
+
 def destupdate(repo, clean=False, check=False):
     """destination for bare update operation
 
@@ -110,14 +119,12 @@
                 (cf bookmark.calculate update),
     - activemark: a bookmark to activate at the end of the update.
     """
-    node = None
-    movemark = activemark = None
+    node = movemark = activemark = None
 
-    node, movemark, activemark = _destupdateobs(repo, clean, check)
-    if node is None:
-        node, movemark, activemark = _destupdatebook(repo, clean, check)
-    if node is None:
-        node, movemark, activemark = _destupdatebranch(repo, clean, check)
+    for step in destupdatesteps:
+        node, movemark, activemark = destupdatestepmap[step](repo, clean, check)
+        if node is not None:
+            break
     rev = repo[node].rev()
 
     _destupdatevalidate(repo, rev, clean, check)