From: Phillip Wood Date: Tue, 07 Apr 2020 15:54:35 GMT Subject: Re: Feature request: rebase -i inside of rebase -i Message-ID: <7babcfdb-5b01-ca6d-2709-4fae582c50e1@gmail.com> In-Reply-To: <60cd00c2-7aba-3d74-11fa-d4443f6cd83e@iee.email> Hi Philip On 01/04/2020 17:43, Philip Oakley wrote: > Hi Phillip, > > On 31/03/2020 14:36, Phillip Wood wrote: >> Hi Philip, George and Johannes >> >> I really like the idea of being able to extend or rewind an existing >> rebase to reedit commits. >> >> On 31/03/2020 11:57, Philip Oakley wrote: >>> Hi george, >>> >>> On 31/03/2020 01:00, George Spelvin wrote: >>>> Thinking about Philip Oakley's suggestion, it dawned on me that >>>> we can *already* do a nested rebase manually, and having a less >>>> manual alias for the procedure would be reasonable. >>>> >>>> Suppose the last four commits are O-A-B-C, and whether they were >>>> created >>>> by this rebase or existed before is irrelevant. >>>> >>>> If I want to rebase --nested -i O, then I --edit-todo and >>> >>> Maybe `--rework` as a possible alternate option name, if the concept of >>> it being truly nested process does not work out? >> >> or `--rewind` ? > > A possibility, though it feels a bit narrow in suggesting the capabilities >> >>>> prepend the following four lines: >>>> reset O >>>> pick A >>>> pick B >>>> pick C >>>> >>>> If a nested rebase command does just that, I think it would cover my >>>> use case.  If it adds a comment saying "nested rebase ends here", >>>> it's easy to cancel the nested rebase if there was a mistake. >>>> >>>> A slightly fancier thing a nestrd rebase could do is see if any of the >>>> newly created picks are also used in merges that were already in the >>>> todo >>>> list.  In that case, follow the pick by a label command and update the >>>> later merge to refer to the label. >> >> If we're going to support rewinding a rebase that creates merges then >> this is a prerequisite otherwise it wont work properly. It will also >> need to update any existing labels that refer to a commits that get >> rewritten when rewinding. > > I would agree that the `label` instruction would need expanding to allow > arbitrary refs (e.g. specific oids and other branches) to be labelled > rather than just a presumed 'HEAD' ref. I did notice the man page > doesn't actually define the format of the extra instructions (there was > fun with awkward chars in label names on Windows). > > I'm of the opinion that we don't re-label/rename the previous labels - > they are what they are, but we do offer the ability to provide new > labels. Hence the extension to the label format to allow the labelling > of arbitrary refs, not just HEAD, along with showing existing progress, > so folks can _see_ the new oids etc. I'm not sure I understand how this would work. Say in the example below I decide I want to rework abc while editing fgh and run 'git rebase --rework abc^'. If we don't update the labels automatically how do I ensure that the merge will pick up the reworked abc as it's parent. #pick abc #label topic #reset cde edit fgh merge topic >> >> When cancelling the nested rebase we need to take care to restore any >> labels to their previous value if they have been updated by the nested >> rebase. We also need to restore the list or rewritten commits so that >> we don't report that we've rewritten the commits from the nested >> rebase that we're aborting. These two requirements unfortunately make >> it difficult to implement the nested rebase just by updating the todo >> list. > > I'm against the original conceptual idea of 'nesting' (or rewinding). > What's done is done, it's in the object store, as is all the old > original work, so we have a wider foundation to build from.  Clearly we > are not in a clean work-state, with the half complete jobs, so it's more > of a recovery activity than clean coding (from the user perspective). I don't like the idea of nesting either but I think it would be useful to be able to get back to a known state when the changes I make with 'rebase --rework' turn out to be a bad idea so I don't throw away all the work that I did before running 'rebase --rework'. I've been using a script that rewinds and I've got myself into situations where a speculative change made while rewinding turned out to be a bad idea and I want to get back to the state before the last rewind. When working on a patch series I can rewind multiple times before completing the rebase as I jump back and forth modifying and rewording each patch. Best Wishes Phillip >> It needs to save the current labels (and reference the commits >> somewhere so they don't get gc'd) and the rewritten-list. `git rebase >> --abort` (or whatever we end up using to abort the nested part of the >> rebase) needs to restore the labels and rewritten-list. I think it >> should probably restore the todo list as well - if the original part >> of the todo list gets edited during the nested rebase should we drop >> those changes to the list or keep them when the nested rebase is aborted? > > If we haven't aborted, then we just have the actual sequence of work, > with some of the commits, ultimately, being left as unconnected stubs > (once their temporary tips have gone upon completion of the rebase - > could they be explicitly dropped?).  On completion, those abandoned > commits could be explicitly marked as having been removed in the various > book-keeping lists and logs (if it was useful and helpful). I think this > is a different conceptual view of the work of the rebase - resolve process. >> >> Best Wishes >> >> Phillip > -- > Philip >