X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=dgit.git;a=blobdiff_plain;f=NOTES.git-debrebase;h=bd6e7151221f67ff54e6100f629c23ce58afaa55;hp=0d7bea84daa3f8f392690d1a70968990749df488;hb=06d712df73af99b1655315d71db571c7315a15c1;hpb=257ed0b02dadd4538f515807189acdd95d88c320 diff --git a/NOTES.git-debrebase b/NOTES.git-debrebase index 0d7bea84..bd6e7151 100644 --- a/NOTES.git-debrebase +++ b/NOTES.git-debrebase @@ -1,170 +1,131 @@ - +# problems / outstanding questions: # -# git-ffqrebase start [BASE] -# # records previous HEAD so it can be overwritten -# # records base for future git-ffqrebase -# git-ffqrebase set-base BASE -# git-ffqrebase -# git-ffqrebase finish -# git-ffqrebase status [BRANCH] +# * new-upstream has an awkward UI for multiple upstream pieces. +# You end up with giant runic command lines. Does this matter / +# One consequence of the lack of richness it can need -f in +# fairly sensible situations. # -# refs/ffqrebase-prev/BRANCH BRANCH may be refs/...; if not it means -# refs/ffqrebase-base/BRANCH refs/heads/BRANCH -# zero, one, or both of these may exist +# * There should be a good convention for the version number, +# and unfinalised or not changelog, after new-upstream. # -# git-debrebase without start, if already started, is willing -# to strip pseudomerges provided that they overwrite exactly -# the previous HEAD -# xxxx is this right ? what matters is have we pushed -# I think in fact the right answer is: -# git-debrebase always strips out pseudomerges from its branch -# a pseudomerge is put in at the time we want to push -# at that time, we make a pseudomerge of the remote tracking -# branch (if raw git) or the dgit view (if dgit) -# for raw git git-ffqrebase, do want preciseley to record -# value of remote tracking branch or our branch, on start, so we -# overwrite only things we intend to -# the previous pseudomerge check for tags and remote branches ? - - -========= - -workflow - - git-debrebase blah [implies start] strips pseudomerge(s) - - commit / git-debrebase / etc. +# * Handing of multi-orig dgit new-upstream .dsc imports is known to +# be broken. They may be not recognised, improperly converted, or +# their conversion may be unrecognised. +# +# * We need to develop a plausible model that works for derivatives, +# who probably want to maintain their stack on top of Debian's. +# downstream-rebase-launder-v0 may be a starting point? +# maybe the hypothetical git-ffqrebase is part of it too. + - dgit --damp-run push - hook: call git-debrebase prep-push adds new pm ? passes --overwrite ? - dgit push does not update remote +# undocumented usages: +# +# git-debrebase [] downstream-rebase-launder-v0 # experimental - commit / git-debrebase / etc. strips pm(s) including last one - dgit push - hook: call git-debrebase prep-push adds new pm ? passes --overwrite ? - dgit push DOES update remote +======================================== - commit / git-debrebase / etc. strips last pm, but arranges - that remade pm will incorporate it +Theory for ffq-prev -Aha! + refs/ffq-prev/REF relates to refs/REF When we strip a pm, we need to maybe record it (or something) as the new start point. -We do this if the pm is contained within the output branch. +When we do a thing + + with no recorded ffq-prev -Actually this is not special to PMs. + ffq-prev is our current tip -We need to record a new to-be-overwritten commit - merge-base( our branch tip, relevant remote ) + obviously it is safe to say we will overwrite this + we do check whether there are not-included changes in the remotes + because if the new ffq-prev is not ff from the remotes + the later pushes will fail -If this is not a descendant of the relevant remote, then we are going -to have a problem when we push so issue a warning or fail. + this model tends to keep ad-hoc commits made on our + tip branch before we did rebase start, in the + `interchange view' and also in the rebase stack. + also we can explicitly preserve with + git-debrebase stitch + It is always safe to rewind ffq-prev: all + that does is overwrite _less_ stuff. -How about + in any case putative ffq-prev must be ff from remote. + Otherwise when we push it will not be ff, even though we have + made pseudomerge to overwrite ffq-prev. So if we spot + this, report an error. see above - git-debrebase start or git-debrebase [continue] + with a recorded ffq-prev - with no recorded will-overwrite + we may need to advance ffq-prev, to allow us to generate + future pseudomerges that will be pushable - putative will-overwrite is - one model: - our current tip - obviously it is safe to say we will overwrite this - we do not need to worry about whether this will - overwrite not-included changes in the remote - because either the will-overwrite is not - ff from the remote (in which case later failure, - see below); or the will-overwrite _is_ ff - from the remote ie our tip is later than the - remote and includes all of its changes + advancing ffq-prev is dangerous, since it might + effectively cancel the commits that will-ovewrite is advanced + over. - this model tends to keep ad-hoc commits made on our - tip branch before we did rebase start, in the - `interchange view' and also in the rebase stack. + ??? advance it to merge-base( current remote, current tip ) + if possible (see above), - ie to current remote, subject + to the condition that that is an ancestor of current tip - other model: - merge-base( current remote, current tip ) + currently this is not implemented - it is safe to overwrite current tip, by the - argument above + better maybe to detect divergence ? but it is rather late + by then! - it is always safe to rewind will-overwrite: all - that does is overwrite _less_ stuff +We check we are ff from remotes before recording new ffq-prev - this is the earliest overwrite we can make that - will be pushable to the remote +======================================== - in practical terms this can only be ff from the - current remote if it is equal to the current remote; - so what we are actually checking below is that our tip - is ff from the remote. This ought to be true before - the first of our rebases. +how to handle divergence and merges (if not detected soon enough) - this model tends to rewind and rebase ad-hoc commits - made on our tip branch before we did rebase start, - this is better +same problem + if merge, look at branches before merge + generate new combined branch + pseudomerge to overwrite merge - in any case putative will-overwrite must be ff from remote. - Otherwise when we push it will not be ff, even though we have - made pseudomerge to overwrite will-overwrite. So if we spot - this, report an error. +current avaiable strategies: - with a recorded will-overwrite + maybe launder foreign branch - we may need to advance will-overwrite, to allow us to generate - future pseudomerges that will be pushable + if foreign branch is nmuish, can rebase it onto ours - advancing will-overwrite is dangerous, since it might - effectively cancel the commits that will-ovewrite is advanced - over. + could merge breakwaters (use analyse to find them) + merge breakwaters (assuming same upstream) + manually construct new patch queue by inspection of + the other two patch queues - we advance it to merge-base( current remote, current tip ) - if possible (see above), - ie to current remote, subject - to the condition that that is an ancestor of current tip + instead of manually constructing patch queue, could use + gbp pq export and git merge the patch queues + (ie work with interdiffs) -In each case we can strip pseudomerges freely, as needed. We do not -want to record what pseudomerges we strip, because whether we need to -keep them depends (only) on whether they have been pushed. + if upstreams are different and one is ahead + simply treat that as "ours" and + do the work to import changes from the other -Is that actually true ? What if the user actually _wanted_ to keep -the pseudomerge despite not having pushed it ? + if upstreams have diverged, can + resolve somehow to make new upstream + do new-upstream on each branch separately + now reduced to previously "solved" problem -In that case we need to advance will-overwrite past it. We could -provide an explicit command to do this: it would advance -will-overwrite to the current tip (see rules above, which show that -this is OK). Or maybe to the last pseudomerge on the current tip, -so that the overall result will be series of pseudomerges. + in future, auto patch queue merge algorithm + determine next patch to apply + there are three versions o..O, l..L, r..R + we have already constructed m (previous patch or merged breakwater) + try using vector calculus in the implied cube and compute + multiple ways to check consistency ? ======================================== -import from gbp - - inputs: - current HEAD (patches-unapplied), - this is going to be the base of the old breakwater - nominated upstream - - checks: - HEAD: = upstream: - upstream..HEAD: is empty (overrideable) - upstremm:debian is empty (overrideable) - - procedure: - construct - run gbp pq import to generate pq branch - new breakwater is - old HEAD - commit to remove d/patches - breakwater pseudomerge with upstream - "rebase" of pq branch, each commit with d/patches stripped - -what about dgit view branch ? -ideally, would make pseudomerge over dgit view -would need to check that dgit view is actually dgit view of - ond of our ancestors -failing that first push will need --overwrite +For downstreams of Debian, sketch of git-ffqrebase + +# git-ffqrebase start [BASE] +# # records previous HEAD so it can be overwritten +# # records base for future git-ffqrebase +# git-ffqrebase set-base BASE +# git-ffqrebase +# git-ffqrebase finish +# git-ffqrebase status [BRANCH]