On Fri, Sep 13, 2019 at 08:06:01PM -0700, Junio C Hamano wrote: > Jeff King <peff@xxxxxxxx> writes: > > > On Fri, Sep 13, 2019 at 03:29:00PM -0700, Junio C Hamano wrote: > > > >> This comment has nothing to do with the change, but the way the > >> patch is presented is quite hard to follow, in that the preimage or > >> the common context lines do not help understand what the new code is > >> doing at all ;-) > >> > >> I'll come back to the remainder of the patch later. Thanks. > > > > I applaud Christian's effort to tease it out into separate patches. > > Ah, no question about it. I have a suspicion that 10/10 alone may > still be a bit too large a ball of wax, but with all the earlier > preparatory steps are bite-sized and trivial to see how they are > correct. > > The "way the patch is presented" comment was not at all about what > Christian did, but was about what the diff machinery computed when > comparing the 9th step Christian created and the final step. In its > attempt to find and align common context lines, it ended up finding > blank lines and almost nothing else in the earlier part of the > patch, not just making it harder to read the new helper function > (i.e. the best way to read record_reused_object(), for example, is > to look only at '+' and ' ' lines, because the '-' lines are > irrelevant), it also made it hard to see what got discarded. Hmm, I see the early parts of this graduated to 'next'. I'm not sure everything there is completely correct, though. E.g. I'm not sure of the reasoning in df75281e78 (ewah/bitmap: always allocate 2 more words, 2019-09-13). I think the "block+1" there is actually because "block" might be "0". Prior to 2820ed171a (ewah/bitmap: introduce bitmap_word_alloc(), 2019-09-13) from the same series, that could never be the case because we know that we always start with at least 32 allocated words. But after that we _could_ start with an empty word array, and allocating "block * 2" would not make forward progress. And then the "2 more words" thing is used as justification in the next patch, 04a32d357f (pack-bitmap: don't rely on bitmap_git->reuse_objects, 2019-09-13). I won't say that there isn't some subtle dependency there, but I certainly don't remember any logic like that at all. ;) So I think it might bear a little more scrutiny. I'm sorry for being so slow on giving it a more careful review. I was traveling for work, then playing catch-up, and am now going on vacation. So it might be a little while yet. -Peff
