Re: [PATCH 1/2 (fix broken test)] rebase -i: add exec command to launch a shell command

> The typical usage pattern would be to run a test (or simply a compilation
> command) at given points in history.
>
> The shell command is ran (from the worktree root), and the rebase is
> stopped when the command fails, to give the user an opportunity to fix
> the problem before continuing with "git rebase --continue".
>
> This needs a little rework of skip_unnecessary_picks, which wasn't robust
> enough to deal with lines like
>
>   exec >"file    name with many spaces"
>
> in the todolist. The new version extracts command, sha1 and rest from
> each line, but outputs the line itself verbatim to avoid changing the
> whitespace layout.

> diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
> index 9f03ce6..93b181e 100755
> --- a/t/t3404-rebase-interactive.sh
> +++ b/t/t3404-rebase-interactive.sh
> @@ -64,6 +64,67 @@ test_expect_success 'setup' '
>  	done
>  '
>  
> +# "exec" commands are ran with the user shell by default, but this may
> +# be non-POSIX. For example, if SHELL=zsh then ">file" doesn't work
> +# to create a file. Unseting SHELL avoids such non-portable behavior
> +# in tests.
> +SHELL=