Add "drop commit-object-name subject" command as another way to
skip replaying of a commit in "rebase -i", and then punish those
who do not use it (and instead just remove the lines) by throwing
a warning.

* gr/rebase-i-drop-warn:
  git rebase -i: add static check for commands and SHA-1
  git rebase -i: warn about removed commits
  git-rebase -i: add command "drop" to remove a commit

"git rebase -i"'s list of todo is made configurable.

* mr/rebase-i-customize-insn-sheet:
  git-rebase--interactive.sh: add config option for custom instruction format

Abandoning an already applied change in "git rebase -i" with
"--continue" left CHERRY_PICK_HEAD and confused later steps.

* js/rebase-i-clean-up-upon-continue-to-skip:
  rebase -i: do not leave a CHERRY_PICK_HEAD file behind
  t3404: demonstrate CHERRY_PICK_HEAD bug

Check before the start of the rebasing if the commands exists, and for
the commands expecting a SHA-1, check if the SHA-1 is present and
corresponds to a commit. In case of error, print the error, stop git
rebase and prompt the user to fix with 'git rebase --edit-todo' or to
abort.

This allows to avoid doing half of a rebase before finding an error
and giving back what's left of the todo list to the user and prompt
him to fix when it might be too late for him to do so (he might have
to abort and restart the rebase).

Signed-off-by: Galan Rémi <remi.galan-alfonso@ensimag.grenoble-inp.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Check if commits were removed (i.e. a line was deleted) and print
warnings or stop git rebase depending on the value of the
configuration variable rebase.missingCommitsCheck.

This patch gives the user the possibility to avoid silent loss of
information (losing a commit through deleting the line in this case)
if he wants.

Add the configuration variable rebase.missingCommitsCheck.
    - When unset or set to "ignore", no checking is done.
    - When set to "warn", the commits are checked, warnings are
      displayed but git rebase still proceeds.
    - When set to "error", the commits are checked, warnings are
      displayed and the rebase is stopped.
      (The user can then use 'git rebase --edit-todo' and
      'git rebase --continue', or 'git rebase --abort')

rebase.missingCommitsCheck defaults to "ignore".

Signed-off-by: Galan Rémi <remi.galan-alfonso@ensimag.grenoble-inp.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Instead of removing a line to remove the commit, you can use the
command "drop" (just like "pick" or "edit"). It has the same effect as
deleting the line (removing the commit) except that you keep a visual
trace of your actions, allowing a better control and reducing the
possibility of removing a commit by mistake.

Signed-off-by: Galan Rémi <remi.galan-alfonso@ensimag.grenoble-inp.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

When skipping commits whose changes were already applied via `git rebase
--continue`, we need to clean up said file explicitly.

The same is not true for `git rebase --skip` because that will execute
`git reset --hard` as part of the "skip" handling in git-rebase.sh, even
before git-rebase--interactive.sh is called.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

A config option 'rebase.instructionFormat' can override the
default 'oneline' format of the rebase instruction list.

Since the list is parsed using the left, right or boundary mark plus
the sha1, they are prepended to the instruction format.

Signed-off-by: Michael Rappazzo <rappazzo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

"git rebase -i" fired post-rewrite hook when it shouldn't (namely,
when it was told to stop sequencing with 'exec' insn).

* mm/rebase-i-post-rewrite-exec:
  t5407: use <<- to align the expected output
  rebase -i: fix post-rewrite hook with failed exec command
  rebase -i: demonstrate incorrect behavior of post-rewrite

Usually, when 'git rebase' stops before completing the rebase, it is to
give the user an opportunity to edit a commit (e.g. with the 'edit'
command). In such cases, 'git rebase' leaves the sha1 of the commit being
rewritten in "$state_dir"/stopped-sha, and subsequent 'git rebase
--continue' will call the post-rewrite hook with this sha1 as <old-sha1>
argument to the post-rewrite hook.

The case of 'git rebase' stopping because of a failed 'exec' command is
different: it gives the opportunity to the user to examine or fix the
failure, but does not stop saying "here's a commit to edit, use
--continue when you're done". So, there's no reason to call the
post-rewrite hook for 'exec' commands. If the user did rewrite the
commit, it would be with 'git commit --amend' which already called the
post-rewrite hook.

Fix the behavior to leave no stopped-sha file in case of failed exec
command, and teach 'git rebase --continue' to skip record_in_rewritten if
no stopped-sha file is found.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>