[Gnu-arch-users] Re: HEADS UP: checksums change is not backward compatible

[Miles Bader]

James Blackwell <address@hidden> writes:
> 67 out of 78 archives (as per mirrors.sourcecontrol.net) are md5
> checksumed. Let me repeat that in a different way.
> 
> 78.2% are about to break.

It's very confusing since there are multiple sorts of compatibility
being talked about at the same time... My understanding of the
situation was that:

   * tla-1.[01] can read anything, sha1 checksums won't bother them

   * tla-1.2-pre0 only understands md5 checksums, and will barf when it
     tries to read an sha1 checksum, and will continue to produce md5
     checksums

   * (pending) tla-1.2-pre1 will produce sha1 checksums, but can read
     both md5 and sha1 checksums[*]

So main problem is that new revisions produced by tla-1.2-pre1 will
contain sha1 checksums and thus won't be readable by people using
tla-1.2-pre0 -- however all the existing archives will continue to be
usable by everybody.

Since the people affected are those running tla-1.2-pre0, they're
presumably `early adopters' types, and probably will quickly upgrade to
tla-1.2-pre1 anyway, so it may not be such a big problem -- *unless* Tom
uses the tla-1.2-pre1 to commit the sha1 changes, in which case many of
these people won't be _able_ to upgrade using their usual method (tla).
That would sort of suck, so it might be a good idea for Tom to use the
old tla for a while past those changes... :-)

[*] This is the crucial point -- backwards compatibility is important,
    even with tla-1.2-pre0

-Miles
-- 
Come now, if we were really planning to harm you, would we be waiting here, 
 beside the path, in the very darkest part of the forest?