bug and proposed fix in "bzr merge --pull --merge"

[Denys Duchier]

The command:

    bzr merge --pull --preview BRANCH

does not always honor the --preview option.  I got burned by this while
writing a tutorial for my class.  Here is a proposed fix:

----8<-------------------------------------------------------------------------
=== modified file 'bzrlib/builtins.py'
--- bzrlib/builtins.py	2011-04-07 11:25:14 +0000
+++ bzrlib/builtins.py	2011-04-12 19:06:31 +0000
@@ -3989,6 +3989,8 @@
             if merger.interesting_files is not None:
                 raise errors.BzrCommandError('Cannot pull individual files')
             if (merger.base_rev_id == tree.last_revision()):
+                if preview:
+                    return self._do_preview(merger)
                 result = tree.pull(merger.other_branch, False,
                                    merger.other_rev_id)
                 result.report(self.outf)

----8<-------------------------------------------------------------------------

Cheers,

--Denys