convert: allow the converter_source to say "skip this revision" If getchanges returns a string, it's assumed to be the id of an already converted revision. We map the current revision to the same revision this converted revision was mapped to. To allow skipping a root revision, getchanges can return the special string 'hg-convert-skipped-revision' (a.k.a. common.SKIPREV), which hopefully won't clash with any real id. The converter_source is responsible for rewriting the parents of the commit objects to make sure the revision graph makes sense.

--- a/hgext/convert/common.py
+++ b/hgext/convert/common.py
@@ -17,6 +17,8 @@ def decodeargs(s):
 
 class NoRepo(Exception): pass
 
+SKIPREV = 'hg-convert-skipped-revision'
+
 class commit(object):
     def __init__(self, author, date, desc, parents, branch=None, rev=None):
         self.author = author