X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=dgit.git;a=blobdiff_plain;f=NOTES.git-debrebase;h=7b9a9b19f39c4b7b3928991ae932d0c3fe0586c9;hp=ac6b88b247947ab9b1b0910149e44746b2f2545f;hb=67db3561da79c090d84228d06adb11546881bba8;hpb=3b8767bcfc8fd709e0f70d876617e69de809e787 diff --git a/NOTES.git-debrebase b/NOTES.git-debrebase index ac6b88b2..7b9a9b19 100644 --- a/NOTES.git-debrebase +++ b/NOTES.git-debrebase @@ -1,65 +1,13 @@ +TODO + reference docs + git-debrebase(1) command line + tutorial + dgit-maint-debrebase(7) + someone should set branch..mergeOptions to include --ff-only ? -# -# 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] -# -# 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 -# -# 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 ? - - -========= - -special commit tags -overall format - [git-debrebase[ COMMIT-TYPE [ ARGS...]]: PROSE, MORE PROSE] - -[git-debrebase: split mixed commit, debian part] -[git-debrebase: split mixed commit, upstream-part] -[git-debrebase: convert dgit import, debian changes] -[git-debrebase breakwater: convert dgit import, upstream changes] - -[git-debrebase upstream-combine . PIECE[ PIECE...]: new upstream] -[git-debrebase breakwater: new upstream NEW-UPSTREAM-VERSION, merge] -[git-debrebase: new upstream NEW-UPSTREAM-VERSION, changelog] - -[git-debrebase: gbp2debrebase, drop patches] -[git-debrebase breakwater: declare upstream] - -m{^\[git-debrebase (?:\w*-)?upstream combine \.((?: $extra_orig_namepart_re)+)\]} - -Every breakwater commit must be a merge. In principle, this is not -necessary. After all, we are relying on the - [git-debrebase breakwater: ...] -commit message annotation in "declare" breakwater merges (which -do not have any upstream changes), to distinguish those breakwater -merges from ordinary pseudomerges (which we might just try to strip). - -However, the user is going to be doing git-rebase a lot. We really -don't want them to rewrite a breakwater base commit. git-rebase -trips up on merges, so that is a useful safety catch. - - -========= + clean up remains of README + + arrange for dgit to automatically stitch on push workflow @@ -68,186 +16,152 @@ workflow commit / git-debrebase / etc. dgit --damp-run push - hook: call git-debrebase prep-push adds new pm ? passes --overwrite ? - dgit push does not update remote + hook: call git-debrebase prep-push dgit push does not update remote + or something, must add patches at least - commit / git-debrebase / etc. strips pm(s) including last one + commit / git-debrebase / etc. strips patches dgit push - hook: call git-debrebase prep-push adds new pm ? passes --overwrite ? - dgit push DOES update remote + hook: call git-debrebase prep-push dgit push DOES update remote commit / git-debrebase / etc. strips last pm, but arranges that remade pm will incorporate it -Aha! +======================================== -When we strip a pm, we need to maybe record it (or something) as the -new start point. +Theory for ffq-prev -We do this if the pm is contained within the output branch. + refs/ffq-prev/REF relates to refs/REF -Actually this is not special to PMs. +When we strip a pm, we need to maybe record it (or something) as the +new start point. -We need to record a new to-be-overwritten commit - merge-base( our branch tip, relevant remote ) +When we do a thing -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. + with no recorded ffq-prev + ffq-prev is our current tip + 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 -How about + 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. - git-debrebase start or git-debrebase [continue] + also we can explicitly preserve with + git-debrebase stitch - with no recorded will-overwrite + It is always safe to rewind ffq-prev: all + that does is overwrite _less_ stuff. - 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 + 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 - 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. + with a recorded ffq-prev - other model: - merge-base( current remote, current tip ) + we may need to advance ffq-prev, to allow us to generate + future pseudomerges that will be pushable - it is safe to overwrite current tip, by the - argument above + advancing ffq-prev is dangerous, since it might + effectively cancel the commits that will-ovewrite is advanced + over. - it is always safe to rewind will-overwrite: all - that does is overwrite _less_ stuff + ??? 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 - this is the earliest overwrite we can make that - will be pushable to the remote + currently this is not implemented - 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. + better maybe to detect divergence ? but it is rather late + by then! - this model tends to rewind and rebase ad-hoc commits - made on our tip branch before we did rebase start, - this is better +We check we are ff from remotes before recording new ffq-prev - 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. + ---------- now follows much the same info in different words ---------- - with a recorded will-overwrite +Re git-debrebase [--noop-ok] stitch - we may need to advance will-overwrite, to allow us to generate - future pseudomerges that will be pushable + we will teach dgit to do + git-debrebase stitch + or some such ? - advancing will-overwrite is dangerous, since it might - effectively cancel the commits that will-ovewrite is advanced - over. +following parts are not implemented and maybe aren't the +best subcommand names etc. - 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 +3. git-debrebase push -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. + like git push only does stitch first + ??? command line parsing! -Is that actually true ? What if the user actually _wanted_ to keep -the pseudomerge despite not having pushed it ? +4. git-debrebase release -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. + stiches, finalises changelog, signs tags, pushes everything + for the future, when there is some automatic builder ======================================== -So, pm handling specifics: - -strategy is to avoid making needless pseudomerges -pseudomerges that exist will be preserved -(by being included in will-overwrite) +import from gbp -This is good because the presence of a pseudomerge means we know we -want to keep it; and that allows explicit control over history detail -level. +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 +that is what is currently implemented -It does mean we must avoid making the pseudomerges unnecessarily. -They should be made just before (ideally, part of) dgit push. +======================================== -1. git-debrebase [-i etc.] +how to handle divergence and merges (if not detected soon enough) - should: - check for will-overwrite - if is already a will-overwrite, fine, do no more - if not: +same problem + if merge, look at branches before merge + generate new combined branch + pseudomerge to overwrite merge - check our origin branch exists and we are ff from it - if not fail +current avaiable strategies: - check our other might-be-pushed to branches - check we are ff from them - if not fail + maybe launder foreign branch - set will-overwrite to something which is ff from - all above branches + if foreign branch is nmuish, can rebase it onto ours - we use our tip, as discussed above - (optionally, can use some other commit which is ff - from all of the above, eg one of them) + 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 -2. git-debrebase stitch + instead of manually constructing patch queue, could use + gbp pq export and git merge the patch queues + (ie work with interdiffs) - makes pseudomerge with will-overwrite - deletes will-overwrite + if upstreams are different and one is ahead + simply treat that as "ours" and + do the work to import changes from the other -3. git-debrebase push + if upstreams have diverged, can + resolve somehow to make new upstream + do new-upstream on each branch separately + now reduced to previously "solved" problem - like git push only does stitch first - ??? command line parsing! + 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 - -[ all this is done now: - 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 -] +For downstreams of Debian, sketch of git-ffqrebase -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 - -should this be called import or gbp2debrebase as it is now ? -gbp uses "import" oddly but I'm tempted to use it normally here. +# 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]