[MERGE RFC] Added option --remember to merge command

[Olaf Conradi]

Hello,

This adds the --remember option to bzr merge for setting parent location.
This closes bug #35350.

Available at revision 1593 of
http://deschacht.student.utwente.nl/bzr/branches/bzr.olaf/

Cheers
 -Olaf

=== modified file 'a/bzrlib/builtins.py'
--- a/bzrlib/builtins.py
+++ b/bzrlib/builtins.py
@@ -1779,6 +1779,10 @@

 class cmd_merge(Command):
     """Perform a three-way merge.
+
+    If there is no default location set, the first merge will set it. After
+    that, you can omit the location to use the default.  To change the
+    default, use --remember.

     The branch is the branch you will merge from.  By default, it will
     merge the latest revision.  If you specify a revision, that
@@ -1812,16 +1816,17 @@
     --force is given.
     """
     takes_args = ['branch?']
-    takes_options = ['revision', 'force', 'merge-type', 'reprocess',
+    takes_options = ['remember', 'revision', 'force', 'merge-type',
'reprocess',
                      Option('show-base', help="Show base revision text in "
                             "conflicts")]

-    def run(self, branch=None, revision=None, force=False, merge_type=None,
+    def run(self, branch=None, remember=False, revision=None,
force=False, merge_type=None,
             show_base=False, reprocess=False):
+        tree = WorkingTree.open_containing(u'.')[0]
         if merge_type is None:
             merge_type = Merge3Merger
         if branch is None:
-            branch = WorkingTree.open_containing(u'.')[0].branch.get_parent()
+            branch = tree.branch.get_parent()
             if branch is None:
                 raise BzrCommandError("No merge location known or specified.")
             else:
@@ -1857,6 +1862,8 @@
             if conflict_count != 0:
                 return 1
             else:
+                if tree.branch.get_parent() is None or remember:
+                    tree.branch.set_parent(branch)
                 return 0
         except bzrlib.errors.AmbiguousBase, e:
             m = ("sorry, bzr can't determine the right merge base yet\n"