2009.08.20 23:12 "[Tiff] Libtiff 3.9.0 Released", by Bob Friesenhahn

2009.08.21 15:26 "Re: [Tiff] Libtiff 3.9.0 Released", by Jay Berkenbilt

This document doesn't clearly answer the first two questions any packager will have about it, which are whether 3.9.0 is ABI compatible with 3.8.2, and if not how about source-code compatible? I could consider dropping 3.9.0 into Fedora 12 if it's ABI compatible, but if not it's probably too late...

Jay Berkenbilt (of the Debian project) expressed the opinion that it is ABI compatible with 3.8.2, that he had done testing in Debian experimental, and was planning to incorporate the code used to produce 3.9.0 into Debian.

Here is the testing I've done to convince myself sufficiently to be willing to put this in debian:

To be even more thorough, it would be useful to make sure that applications that use both the rgba image interface and the read scanlines interface work on both 32-bit and 64-bit systems, but having maintained tiff for debian since 2004 (when I helped manage the transition required as a result of unintentional ABI changes somewhere between 3.5.7 and 3.6.1) and having blocked at least two unintended ABI changes in the mean time, I am reasonably confident that my testing methods are sufficient.

In particular, note that 3.9.0beta was not ABI compatible with 3.8.2, but the changes introduced that broke compatibility were corrected in the 3.9 branch subsequently.

I will be uploading 3.9.0 into debian unstable today. If there are any ABI breakages that I missed, they will likely show up very quickly, and I will make sure that I am on top of them. If there is not a rash of new libtiff bugs traceable to ABI changes in debian over the next several days, I think we can be quite confident that 3.9.0 is ABI compatible with 3.8.2, and that it would be safe for Fedora 12.

Hope that helps.

Jay Berkenbilt <ejb@ql.org>