Re: Checksum failure: serious problem or not?

[Larry Jones]

ajrijnberg writes:
> 
> I sometimes get the following error message when running "cvs up":
> cvs update: checksum failure after patch to some_dir/some_file.c; will
> refetch
> 
> Is this serious? It seems that, after the update, the file in particular
> is correct...
> What is the reason for this message?

When updating an unmodified file, the CVS server usually sends a patch
to the client rather than sending the whole file (since a patch can be
significantly smaller).  Just to be sure that everything works
correctly, it also sends a checksum for the file.  After patching, the
client computes a checksum for its file and compares it against the
server's checksum.  If they don't match, you get the above message and
the client discards the patched file and downloads the whole thing from
the server.  That implies that the file was modified but CVS didn't know
about it.  CVS uses the file's timestamp to detect modifications, so
either the modification didn't affect the timestamp or something reset
the timestamp afterwards.

-Larry Jones

I've got more brains than I know what to do with. -- Calvin