This is a thing without a clear answer.

1. Makefile.am was changed by upstream from -version-info 19:0:0 to -version-info 20:0:1, so that's good.
2. But, both version-info strings lead to libproj.so.19 under the elf-linux-gnu platform. This is intentional and not completely wrong, but it's also not completely right, as it breaks certain program expectations.
3. One could either try to fix libtool (which isn't all that easy given tarballs ship their own copy of libtool),
4. Upstream could add ELF symbol version maps, or
5. Upstream could just bump it to 20:0:0.

Libor Pechacek (LPechacek) - over 3 years ago

Thanks, Jan, for the fast response. I've in the meantime also studied the problem and figured out that the number comes from libtool. Reading the rules for version-info (https://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html#Updating-version-info), I would say all is fine. current was increased and revision reset because an interface was added. age was increased for the same reason. Given that no interfaces have been removed (only deprecated), age didn't have to be reset to zero. The resulting .so version 19 is then OK, in my opinion, as no interfaces have been removed or altered and I'm for keeping the status quo.

---

Jan Engelhardt (jengelh) - over 3 years ago

reviewer

Even though no interface have been removed, the loader (/lib64/ld.so) — and package manager too — can't tell from the name alone if a "libproj.so.19" has the new interface or not, which is a problem if you have a package/program that may be using the new interface.