Empty commits after GitHub squash merge and rebase

[pgr0ss]

I am seeing empty commits after my common workflow, and I'm wondering if I'm doing something wrong or not quite the jj way.

In short, I am using jj with GitHub, and our GitHub pull requests are squashed before merging, which generates a new git commit. Then, when I rebase my local branch onto main with jj, it leaves an empty commit in the history. It's the same description as what was merged in GitHub, but the contents are empty.

Local example simulation:

Start with a simple linear history:

> jj log
@  vnmvnyzt [email protected] 2025-12-15 14:19:23 35199b37
│  (empty) (no description set)
○  xlvlkont [email protected] 2025-12-15 14:19:23 git_head() f38ff61d
│  three
○  vyuusxmv [email protected] 2025-12-15 14:19:10 9b115407
│  two
○  psuxvqox [email protected] 2025-12-15 14:18:56 06787a5f
│  Initial commit
◆  zzzzzzzz root() 00000000

Then simulate a squash merge to "main" (in this case, psuxvqox):

> jj duplicate -r vy -d p
Duplicated 9b11540788ee as xwpuulou efd4e0ac two

> jj log
@  vnmvnyzt [email protected] 2025-12-15 14:19:23 35199b37
│  (empty) (no description set)
○  xlvlkont [email protected] 2025-12-15 14:19:23 git_head() f38ff61d
│  three
○  vyuusxmv [email protected] 2025-12-15 14:19:10 9b115407
│  two
│ ○  xwpuulou [email protected] 2025-12-15 14:20:13 efd4e0ac
├─╯  two
○  psuxvqox [email protected] 2025-12-15 14:18:56 06787a5f
│  Initial commit
◆  zzzzzzzz root() 00000000

Now, I rebase my local changes on top of "main":

> jj rebase -b xl -d xw
Rebased 3 commits to destination
Working copy  (@) now at: vnmvnyzt 2145c605 (empty) (no description set)
Parent commit (@-)      : xlvlkont 9adb5f1b three

> jj log
@  vnmvnyzt [email protected] 2025-12-15 14:20:34 2145c605
│  (empty) (no description set)
○  xlvlkont [email protected] 2025-12-15 14:20:34 git_head() 9adb5f1b
│  three
○  vyuusxmv [email protected] 2025-12-15 14:20:34 ec5942dc
│  (empty) two
○  xwpuulou [email protected] 2025-12-15 14:20:13 efd4e0ac
│  two
○  psuxvqox [email protected] 2025-12-15 14:18:56 06787a5f
│  Initial commit
◆  zzzzzzzz root() 00000000

Here, you can see the empty commit: (empty) two. The rebase correctly realizes that all of the changes in two are already upstream, but it leaves the empty commit. I then have to go in an manually abandon it.

I know I could target the rebase and manually exclude the two commit. But I will often do the simpler jj rebase -b @ -d main so I don't have to look up the refs.

[martinvonz]

You can pass --skip-emptied to jj rebase to have changes be abandoned if they become empty. There's also a planned jj git sync command (#1039) that will probably take care of that.

[pgr0ss]

Thanks!