The only possible way that I know of would be to convert your repository into a new Mercurial repository, using Mercurial's Convert extension with the --authors
option.
During conversion, you can change the authors' names by providing a text file with a "mapping".
Quote from the second link:
Convert can also remap author names during conversion, if the
--authors
option is provided. The argument should be a simple text file maps each source commit author to a destination commit author. It
is handy for source SCMs that use UNIX logins to identify authors (eg:
CVS). Example:
john=John Smith <John.Smith@someplace.net>
tom=Tom Johnson <Tom.Johnson@bigcity.com>
Downside:
You would have to delete the repository on Google Code and replace it with the converted one, which would mean that everyone who cloned the old repository would need to delete their local copies and pull again.
Deleting and replacing the repo on the server may feel a bit clunky, but AFAIK there's no other way to change the author names afterwards.