2012.01.24 23:24 "Re: [Tiff] update on tiff 4.x in debian", by Jay Berkenbilt
On 01/23/2012 12:50 PM, Bob Friesenhahn wrote:
I will get to this as soon as I can, but I will probably want to get someone from the debian release team to look at it. Maybe Tom Lane can look at it too -- he probably has more experience with this than I do.
Sorry, I don't know much of anything about versioned symbols. My reaction TBH is that it's a big mistake to be changing 3.9.x's ABI at this late date, and that if this ships it will be a blocker to ever again updating libtiff 3.9 in existing RHEL branches.
The 3.9.x ABI would not change by default. If a distribution chooses to enable versioned symbols then it also needs to take responsibility to assure that all software is built consistently and that there is no way to introduce binaries which depend on the former ABI. This is most easily performed at beginning of a major baseline cycle, which typically occurs only every few years. Of course, the software could simply be updated to work with libtiff 4.0 instead.
Debian did previously jump through all these hoops in order to add versioned symbols to old IJG JPEG 6b so that it could introduce IJG JPEG 7 and IJG JPEG 8.
We have a plan for debian. I will be preparing an upload of 3.9.5 with versioned symbols (I'll grab from CVS) to "experimental" as well as 4.0.0 with versioned uploads so the release team can give them a shakedown, but they looked at your CVS and said the changes looked right. If that goes okay, then I would suggest 3.9.6 and 4.0.1 releases. Then, for debian, we will immediately upload 3.9.6 with versioned symbols and jump through the hoops required, though the release team says old binaries should continue to work. I haven't personally tested that. At some point after that, the "tiff" package in debian will become 4.0, and the tiff 3 support will move into a separate "tiff3" package. This may be able to happen fairly soon after we get 3.9.6 with versioned symbols transitioned, or the release team may decide that it has to wait until after Wheezy is released. While no one has brought it up, Ubuntu is heading toward an LTS release this coming April, and it might be a good idea for debian to wait on making the default tiff based on 4.0 until after that freezes so we don't leak problems into there. But at this point, there is a clear path forward to getting the default tiff in debian based on 4.0. It will take several months to happen, but it will happen.
I won't bother this list with the blow by blow, but I will report back once the release team says that the new packages with versioned symbols are acceptable for them to bless the plan of eventually transitioning to 4.0. At that time, hopefully you can push out 3.9.6 and 4.0.1.