[PATCH v4 0/2] rebase -i: extend rebase.missingCommitsCheck

To prevent mistakes when editing a branch, rebase features a knob, rebase.missingCommitsCheck, to warn the user if a commit was dropped. Unfortunately, this check is only effective for the initial edit, which means that if you edit the todo list at a later point of the rebase and drop a commit, no warnings or errors would be issued.

This adds the ability to check if commits were dropped when editing the todo list with `--edit-todo', and when resuming a rebase.

The first patch moves moves check_todo_list_from_file() and `edit_todo_list_advice' from sequencer.c to rebase-interactive.c so the latter can be used by edit_todo_list() and todo_list_check(). The second patch adds the check to `--edit-todo' and `--continue' and tests.

This is based on 393adf7a6f ("sequencer: directly call pick_commits() from complete_action()", 2019-11-24).

The tip of this series is tagged as "edit-todo-drop-v4" at https://github.com/agrn/git.

Changes since v3:

 - Set the fake editor in a subshell in the tests to avoid conflicts with
   pw/post-commit-from-sequencer.

 - Added the `dropped' file to indicate that the todo list is incorrect
   (ie. no invalid commands or dropped commits.)

 - The todo list is copied only if it is correct.

 - sequencer_continue() checks the todo list for dropped commits only
   when `dropped' exists.

 - Added a new test to check that `rebase --continue' does not warn for
   dropped commits after solving a conflict.  This was provided by
   Phillip Wood.

 - check_todo_list_from_file() no longer prints `edit_todo_list_advice'
   if there is dropped commits since todo_list_check() do it now.

Alban Gruin (2):
  sequencer: move check_todo_list_from_file() to rebase-interactive.c
  rebase-interactive: warn if commit is dropped with `rebase
    --edit-todo'

 rebase-interactive.c          |  89 ++++++++++++++++++++++++---
 rebase-interactive.h          |   5 ++
 sequencer.c                   |  51 ++++------------
 sequencer.h                   |   2 +-
 t/t3404-rebase-interactive.sh | 109 ++++++++++++++++++++++++++++++++++
 5 files changed, 206 insertions(+), 50 deletions(-)

Diff-intervalle contre v3: 1: 996045a300 = 1: 996045a300 sequencer: move check_todo_list_from_file() to rebase-interactive.c 2: ba6d27e5b4 < -: ---------- rebase-interactive: warn if commit is dropped with `rebase --edit-todo' -: ---------- > 2: 11b0e1e78c rebase-interactive: warn if commit is dropped with `rebase --edit-todo'