Hi Martin, No problem. I was thinking of the peek/pop pattern as well. :) If you don't mind, can you please go ahead and submit a patch for this? Thanks so much.
Isaac -----Original Message----- From: Martin Ågren [mailto:martin.ag...@gmail.com] Sent: Friday, April 20, 2018 1:08 AM To: Junio C Hamano <gits...@pobox.com> Cc: Isaac Chou <isaac.c...@microfocus.com>; Johannes Schindelin <johannes.schinde...@gmx.de>; Jonathan Tan <jonathanta...@google.com>; git@vger.kernel.org Subject: Re: [BUG] Git fast-export with import marks file omits merge commits On 20 April 2018 at 00:48, Junio C Hamano <gits...@pobox.com> wrote: > Isaac Chou <isaac.c...@microfocus.com> writes: > >> I inspected the source code (builtin/fast-export.c) for the >> fast-export issue I encountered, and it looks like the merge commit >> is discarded too early by the call to object_array_pop() after only >> one of the two UNSHOWN parents is processed in the method >> handle_tail(). The poped merge commit still has one UNSHOWN parent, >> therefore it is not processed and is lost in the output. Can someone >> advise me on how to submit a code change or bug report in order to >> get the fix into the code base? > > There indeed are some differences between v2.14 and v2.15 around the > code that returns early when has_unshown_parent() says "yes" [*1*], > but the decision to return early when the function says "yes" hasn't > changed between that timeperiod---it dates back to f2dc849e ("Add 'git > fast-export', the sister of 'git fast-import'", 2007-12-02), i.e. the > very beginning of the program's life. > > I'll CC those who wrote the original and b3e8ca89 ("fast-export: do > not copy from modified file", 2017-09-20) and 71992039 > ("object_array: add and use `object_array_pop()`", 2017-09-23), which > are the only two commits that touch the surrounding area during that > timeperiod, to ask if something jumps at them. > > Thanks. > > > [Footnotes] > > *1* An excerpt from 'git diff v2.14.0 v2.15.0 builtin/fast-export.c' > reads like so: > > diff --git a/builtin/fast-export.c b/builtin/fast-export.c index > d412c0a8f3..2fb60d6d48 100644 > --- a/builtin/fast-export.c > +++ b/builtin/fast-export.c > ... > @@ -630,15 +645,15 @@ static void *anonymize_tag(const void *old, size_t *len) > return strbuf_detach(&out, len); } > > -static void handle_tail(struct object_array *commits, struct rev_info > *revs) > +static void handle_tail(struct object_array *commits, struct rev_info *revs, > + struct string_list *paths_of_changed_objects) > { > struct commit *commit; > while (commits->nr) { > - commit = (struct commit *)commits->objects[commits->nr - > 1].item; > + commit = (struct commit *)object_array_pop(commits); > if (has_unshown_parent(commit)) > return; > - handle_commit(commit, revs); > - commits->nr--; > + handle_commit(commit, revs, paths_of_changed_objects); > } > } Indeed. This looks wrong and the guilty person would be me. If my 71992039 ("object_array: add and use `object_array_pop()`", 2017-09-23) would instead have done something like s/commits->nr--/(void)object_array_pop(commits)/ it would not have screwed up as much. It could also use a peek+pop-pattern. Isaac, are you up for submitting a patch? Just let me know if you encounter any issues. Otherwise, I can submit a patch shortly since I was the one who dropped the ball originally. Thanks for diagnosing this. Martin
