jj rebase --after main causes thread panic

[sean-c-johnston]

Description

When using jj rebase with no -r -s or -b argument, I believe the default behaviour is the same as jj rebase -b @ <args>.

It seems that --after is not a valid argument to combine with -b, but the cli does not properly display a friendly error in the "implicit" case.

Steps to Reproduce the Problem

1. Run jj rebase --after <revision> in a jj repository.

Expected Behavior

Displaying the same error as explicitly running jj rebase -b @ --after main:

error: the argument '--branch <BRANCH>' cannot be used with '--insert-after <INSERT_AFTER>'

Actual Behavior

❯ jj rebase --after main

thread 'main' panicked at cli/src/commands/rebase.rs:274:14:
clap should enforce -d when used with -b

Output from running with RUST_BACKTRACE=full:

stack backtrace:
   0:        0x1031d2e74 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h1f3776e0b5c7517d
   1:        0x1031f4b1c - core::fmt::write::heedef092c8c0962e
   2:        0x1031cdff8 - std::io::Write::write_fmt::h7178e8e2ea928914
   3:        0x1031d2ccc - std::sys_common::backtrace::print::h417292deb95532ed
   4:        0x1031d48bc - std::panicking::default_hook::{{closure}}::h0cb68f1228c4613a
   5:        0x1031d45b0 - std::panicking::default_hook::h24535936bc1f51de
   6:        0x1031d5174 - std::panicking::rust_panic_with_hook::h5db4d2345b297bed
   7:        0x1031d4ba4 - std::panicking::begin_panic_handler::{{closure}}::h3fd558f09a0d5492
   8:        0x1031d32fc - std::sys_common::backtrace::__rust_end_short_backtrace::hfc76eebe1ce501b2
   9:        0x1031d4914 - _rust_begin_unwind
  10:        0x103248150 - core::panicking::panic_fmt::hc2b459a5bd3dce66
  11:        0x1031f2744 - core::panicking::panic_display::hf23c98a61b03dc30
  12:        0x103248124 - core::option::expect_failed::hd7f592634f4db1af
  13:        0x102a93268 - jj_cli::commands::rebase::cmd_rebase::h22f4bf097df4c29c
  14:        0x102abedd4 - jj_cli::commands::run_command::h9b85c15c858d0dc4
  15:        0x10291fc14 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hac56075794e9a253
  16:        0x102a29b74 - jj_cli::cli_util::CliRunner::run::h174009057440dd27
  17:        0x10281e404 - jj::main::hedfc4096854b2cbc
  18:        0x10281e384 - std::sys_common::backtrace::__rust_begin_short_backtrace::h8e2c448e74e53942
  19:        0x10281e39c - std::rt::lang_start::{{closure}}::h58b1bf8200ea7633
  20:        0x1031c5dfc - std::rt::lang_start_internal::hecc68fef83c8f44d
  21:        0x10281e448 - _main

Specifications

• Platform: macOS
• Version: jj 0.22.0-1d7aaa6f8d8db233e25fa4a3627506f280a8c2ea

Specifically the openSSH fork by bnjmnt4n

[yuja]

cc @bnjmnt4n

It might be easier to add let Some(..) = .. else { return cli_error(..); } instead of relying on clap.

[bnjmnt4n]

I've created a quick PR #4779 to fix this. In the future, I believe we should be able to remove this restriction anyway and allow -b with --after/--before.