convert: clear the dirstate before a conversion, invalidate it afterwards Clearing it before the conversion protects us from whatever data were there (file copies in particular). Invalidating it after the conversion avoids writing a possibly inconsistent dirstate to disk.

% basic
% unknown
*** [alias] unknown: command bargle is unknown
% ambiguous
*** [alias] ambiguous: command s is ambiguous
% recursive
*** [alias] recursive: circular dependency on recursive
adding foo
% with opts
C foo