On 7/21/2010 5:00 PM, Robert Ramey wrote:
Ryan Gallagher wrote:
Based upon your messages, it's not clear to me what this "fix" does. Does it make it so that serialization in 1.44 will be able to read binary archives from 1.41 or does it make it so that serialization in 1.44 will be able to read binary archives from 1.42/43? Or somehow both? Is there a trac issue?
I'll recapilate the history in a little more detail.
a) 1.41 - every thing fine b) 1.42 - 17 November 2009? make some fixes to addressess warning messages. This actually exposed some dependence on undefined behaviorj so it was judged a good thing c) These changes broke MPI but this was not noticed at the time. Doug Gregor checked in some changes to the serialization library to address the MPI issue. But this broke compatibility with previous binary_archives. d) 1.43 released I spent a fair amount of time reconciling all the above. This does require a change in archives which derive from binary_?archive. I am sorry about that, but I could find no other way to reconcile all the requirments. as far as I could see, the changes should be small and perhaps trivial since MPI doesn't have support previous versions.
That sentence doesn't parse. I think you're missing a "to" in there. MPI doesn't have "to" support previous versions, presumably because the serialized forms are only traveling across a wire and are never persisted to disk. Is that right? Matthias, is that assumption correct.
I don't know as I haven't looked into it in detail and there are some macros whose function I don't understand. e) My method of handling breaking changes in serialization formats is to include the archive version implemenation number in the archive header so that subsequent code can handle old archives. This was stymied by the fact that in step b) above, I failed to increment this library version # - (I was only fixing a few warnings - right?). So I've had to add a program which will fix native binary archives writting by versions 1.42 and 1.43. I realise this is a huge pain but I don't see any other way.
Normally I would say don't hold a release for any issue in a particular library. I'm giving myself a break here because the longer I wait the larger the number of archives will be created that require the fix. It's like an oil spill - the longer you let it go the bigger the problem.
I hope that clarifies things.
Not quite there yet. You didn't answer Ryan's questions directly. Let me see if I can:
Based upon your messages, it's not clear to me what this "fix" does.
It makes binary archives distinguishable from their incompatible pre-1.42 variants. It provides a standalone utility to help users fix their broken binary archives from 1.42 and 1.43. It requires users that inherit from a binary archive to manually fix their code. It (does/does not?) help users identify these places in their code.
Does it make it so that serialization in 1.44 will be able to read binary archives from 1.41
Yes(?)
or does it make it so that serialization in 1.44 will be able to read binary archives from 1.42/43?
No.
Or somehow both? Is there a trac issue?
No(?) -- Eric Niebler BoostPro Computing http://www.boostpro.com