Hi Roland, On Wed, Aug 07, 2024 at 09:00:47AM +0200, Roland Clobus wrote: > There is another bit of information that I didn't share yet: these > diversions are only temporary. The diversions are made during the > construction of the live image (when other packages are installed and the > packages that have diversions will not upgrade), and reverted before the > image is finalised. They are not present inside the live images. They 'only' > serve the purpose of saving time by performing a no-op during the > construction of the live image.
As far as I understand the code, your construction applies to multiple releases at the same time and for each release I would agree that you only need one diversion. The need for duplicating the diversions arises from different releases requiring different diversions. In principle, you could also carry forward a variable say USR_MOVED that you set to "" for bookworm and earlier and to "/usr" for trixie and later and then prepend this to your diversions. If you were to use the /usr-moved diversions on a bookworm or earlier tree, they have the same effect as doing nothing. In particular, you are expecting the relevant file to be renamed (via --rename). So your diversion would apparently work, but it would not actually move the diverted file out of place. Then you overwrite the diverted file and when you remove the diversion you expect to get back the original file, but instead you keep your temporary changes. I note that if live-build in forky also wants to support bookworm, the "begin-remove-after: trixie" I used in my patch should be bumped to "begin-remove-after: forky". The main benefit I see in my approach is that it becomes simpler to eventually remove this compatibility code as it is clearly identified when to remove what code in a machine-readable way and the Debian janitor will be able to create merge requests cleaning up this code. That said, you may prefer another implementation and that's fine. > Ah, I (erroneously) thought that the whole purpose of moving the files to > /usr was to (eventually) get rid of the symlinks (in forky+N). It is difficult to strike a good balance on how much detail we give. Too much text and people stop reading. Too little and misunderstandings happen. The fundamental reason for the moves is that we experienced bugs (file loss) as a result of exercising undefined behaviour in dpkg and in moving files from / to /usr (in data.tar of binary .debs), we operate dpkg within its specification again reducing the risk of unexpected file loss. As mentioned in my previous reply, the referencing of files remains unaffected - except when the references apply to the dpkg database as diversions do. Hope this clarifies. Thanks for bearing with this transition. Helmut
