libsubid ABI version

[floppym]

shadow-4.20.0 changed the libsubid soname from libsubud.so.5 to libsubid.so.6. This was done by @hallyn in d57c8e3.

As far as I can tell, there was no ABI change between shadow-4.19.4 and shadow-4.20.0.

I ran the two versions through abi-compliance-checker, and it agrees.

compat_report.html

Why was libsubid_abi_major incremented when there appears to have been no breaking ABI change?

[hallyn]

On Thu, Jul 30, 2026 at 12:54:35PM -0700, Mike Gilbert wrote: floppym created an issue (shadow-maint/shadow#1707) shadow-4.20.0 changed the libsubid soname from `libsubud.so.5` to `libsubid.so.6`. This was done by @hallyn in d57c8e3. As far as I can tell, there was no ABI change between shadow-4.19.4 and shadow-4.20.0. I ran the two versions through abi-compliance-checker, and it agrees. [compat_report.html](https://github.com/user-attachments/files/30561037/compat_report.html) Why was libsubid_abi_major incremented when there appears to have been no breaking ABI change?

Hm, as explained in the commit, it was because of the introduction of the deterministic subid calculation mode, but I guess that's not an ABI change per se. So perhaps I was wrong to bump it.

[floppym]

Okay. Let's keep it in mind for next time.