Comment 31 for bug 1895643

For the record, I talked to Robie who is on the SRU team, and he said:

 « IMHO, I think that breaking the other packages to bump Thunderbird is inevitable. Technically I don't think that's within the remit of the SRU team - it's a TB thing. I think we should figure out how to mitigate as much as possible, document and publicise the breakage as best as we can, then break it. »

We went on to discuss how "apt upgrade" would behave (vs "apt dist-upgrade"), I tested and I observed that "apt upgrade" wouldn't proceed to the upgrade as it doesn't remove broken packages.
The "Software Updater" GUI however does the right thing, even if the UX will be slightly unusual for most users (assuming they have tinyjsd or jsunit installed): it will first warn that "Not all updates can be installed", and propose a partial upgrade, which does the right thing, warning that it's going to remove two packages (tinyjsd and jsunit) and upgrade 5 packages (thunderbird*), and offering to proceed.

We agreed that I would bring up the topic with the technical board on their mailing list.