2012.01.25 14:28 "Re: [Tiff] update on tiff 4.x in debian", by Jay Berkenbilt

On 01/24/2012 07:11 PM, Bob Friesenhahn wrote:

It seems that someone should verify that old binaries will continue to work. Presumably they will work until someone introduces another libtiff version into the mix.

My testing plan is going to be to build versioned 3.9.5+ and make sure that binaries linked with the non-versioned libraries work, which they are apparently supposed to. Then I'll link something with the versioned library and make sure it does the right thing with the dual version case. Since tiff 4 will have a different soname, it should be fine. In addition to the usual soname thing, Debian has an additional mechanism using a shlibs file, understood by the packaging system, to specify the minimum debian package version required for a shared library. Part of the packaging change will to be to bump that so that anything that links with the versioned library will automatically get a dependency on the minimum devuab version of the library that includes versioned symbols. It is that mechanism that makes it possible for debian to just kick off automatic rebuilds of all the packages that depend on tiff before introducing the new library while still ensuring that older binaries continue to work.

Sounds fine. The main thing to decide is if 4.0.1 should enable versioned symbols by default.

I think I would vote to have it enabled by default, but it doesn't matter for the debian case since I will explicitly enable it. I guess I don't have a clear enough concept of what a surprise change between 4.0.0 and 4.0.1 would mean to other distributions, but it seems like if it's true that binaries linked with non-versioned symbols still work once versions have been added, it should be okay, right? But anyway my views should be taken with a grain of salt as I have no actual experience with this issue.

When I report back, I'll give a full description of the testing I did and the results.

--Jay