ag/sequencer-reduce-rewriting-todo, was Re: What's cooking in git.git (Dec 2018, #02; Fri, 28)

> * ag/sequencer-reduce-rewriting-todo (2018-11-12) 16 commits
>  . rebase--interactive: move transform_todo_file() to rebase--interactive.c
>  . sequencer: fix a call to error() in transform_todo_file()
>  . sequencer: use edit_todo_list() in complete_action()
>  . rebase-interactive: rewrite edit_todo_list() to handle the initial edit
>  . rebase-interactive: append_todo_help() changes
>  . rebase-interactive: use todo_list_write_to_file() in edit_todo_list()
>  . sequencer: refactor skip_unnecessary_picks() to work on a todo_list
>  . sequencer: change complete_action() to use the refactored functions
>  . sequencer: make sequencer_make_script() write its script to a strbuf
>  . sequencer: refactor rearrange_squash() to work on a todo_list
>  . sequencer: refactor sequencer_add_exec_commands() to work on a todo_list
>  . sequencer: refactor check_todo_list() to work on a todo_list
>  . sequencer: introduce todo_list_write_to_file()
>  . sequencer: refactor transform_todos() to work on a todo_list
>  . sequencer: make the todo_list structure public
>  . sequencer: changes in parse_insn_buffer()
> 
>  The scripted version of "git rebase -i" wrote and rewrote the todo
>  list many times during a single step of its operation, and the
>  recent C-rewrite made a faithful conversion of the logic to C.  The
>  implementation has been updated to carry necessary information
>  around in-core to avoid rewriting the same file over and over
>  unnecessarily.
> 
>  With too many topics in-flight that touch sequencer and rebaser,
>  this need to wait giving precedence to other topics that fix bugs.
> 
>