Hi Alex,
On Mon, Apr 27, 2020 at 5:30 AM Berg, Alexander <alexander.berg@xxxxxxxx> wrote:
>
> Dear *,
>
> AFAIS there are (at least) two bugs in git-rebase at the moment.
> Those findings below occured on a simple branch, without an upstream.
>
> If you wish to rebase history and drop all empty commits, e.g.
> git rebase --root --empty drop
> those empty commits are still in place after the operation comletes.
> With git v2.14.xx this operation ("--drop-empty") drops those empty
> commits as expected.
> Is there a new option to be used here or something?
> Or is it just broken?
>From the documentation:
--empty={drop,keep,ask}::
How to handle commits that are not empty to start and are not
clean cherry-picks of any upstream commit, but which become
empty after rebasing (because they contain a subset of already
upstream changes).
With 2.26.2, to drop commits that _start_ empty, you'd use an
interactive rebase and remove the 'pick' lines associated with those
commits. In 2.27, we'll mark such commits with an "# empty" trailer,
and will also provide the --no-keep-empty flag to just automatically
drop them. (See
https://lore.kernel.org/git/3a5bedc68d696f19ab8eb40d1af8abd42172219f.1586573068.git.gitgitgadget@xxxxxxxxx/,
or check out the 'next' branch of git.git if you'd like to try it
sooner.)
> As I've experimented with some new options for the above command,
> it seems that user input checking isn't done properly for "--fork-point".
> I've tried
> git rebase --root --empty drop --fork-point --rebase-merges
> (yes, --fork-point usage is wrong here) and got
> Segmentation fault (core dumped)
>
> A colleague of mine looked into this:
> $ gdb /bin/git
> (gdb) set args rebase --root --empty drop --fork-point --rebase-merges
> (gdb) run
> Starting program: /bin/git rebase --root --empty drop --fork-point --rebase-merges
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib64/libthread_db.so.1".
>
> Program received signal SIGSEGV, Segmentation fault.
> is_per_worktree_ref (refname=0x0) at refs.c:725
> 725 starts_with(refname, "refs/bisect/") ||
> Missing separate debuginfos, use: debuginfo-install glibc-2.17-292.el7.x86_64 pcre-8.32-17.el7.x86_64 zlib-1.2.7-18.el7.x86_64
> (gdb) bt
> #0 is_per_worktree_ref (refname=0x0) at refs.c:725
> #1 ref_type (refname=refname@entry=0x0) at refs.c:760
> #2 0x00000000005739c9 in files_reflog_path (refs=0x90ce30, sb=0x7fffffffc5e0, refname=0x0) at refs/files-backend.c:176
> #3 0x000000000057402a in files_for_each_reflog_ent (ref_store=<optimized out>, refname=0x0, fn=0x4d4d20 <collect_one_reflog_ent>, cb_data=0x7fffffffc640)
> at refs/files-backend.c:2060
> #4 0x00000000004d4f4b in get_fork_point (refname=0x0, commit=0x91cff0) at commit.c:933
> #5 0x0000000000475e69 in cmd_rebase (argc=0, argv=0x7fffffffdd20, prefix=<optimized out>) at builtin/rebase.c:2082
> #6 0x0000000000406cd0 in run_builtin (argv=0x7fffffffdd20, argc=6, p=0x8b3f40 <commands+2016>) at git.c:444
> #7 handle_builtin (argc=6, argv=argv@entry=0x7fffffffdd20) at git.c:674
> #8 0x0000000000407bee in run_argv (argv=0x7fffffffda80, argcp=0x7fffffffda8c) at git.c:741
> #9 cmd_main (argc=6, argc@entry=7, argv=0x7fffffffdd20, argv@entry=0x7fffffffdd18) at git.c:872
> #10 0x0000000000406910 in main (argc=7, argv=0x7fffffffdd18) at common-main.c:52
> (gdb) list
> 720
> 721 static int is_per_worktree_ref(const char *refname)
> 722 {
> 723 return !strcmp(refname, "HEAD") ||
> 724 starts_with(refname, "refs/worktree/") ||
> 725 starts_with(refname, "refs/bisect/") ||
> 726 starts_with(refname, "refs/rewritten/");
> 727 }
> 728
> 729 static int is_pseudoref_syntax(const char *refname)
> (gdb)
>
>
> With kind regards,
> Alex
Thanks for the report; when the tests finish at
https://github.com/git/git/pull/771, I'll submit the patch to the
list.
Elijah
