Re: [PATCH v2 2/2] rebase --exec: make it work with --rebase-merges

> On 06/08/18 10:52, Johannes Schindelin via GitGitGadget wrote:
> > 
> > From: Johannes Schindelin <johannes.schindelin@gmx.de>
> > 
> > The idea of `--exec` is to append an `exec` call after each `pick`.
> > 
> > Since the introduction of fixup!/squash! commits, this idea was extended
> > to apply to "pick, possibly followed by a fixup/squash chain", i.e. an
> > exec would not be inserted between a `pick` and any of its corresponding
> > `fixup` or `squash` lines.
> > 
> > The current implementation uses a dirty trick to achieve that: it
> > assumes that there are only pick/fixup/squash commands, and then
> > *inserts* the `exec` lines before any `pick` but the first, and appends
> > a final one.
> > 
> > With the todo lists generated by `git rebase --rebase-merges`, this
> > simple implementation shows its problems: it produces the exact wrong
> > thing when there are `label`, `reset` and `merge` commands.
> > 
> > Let's change the implementation to do exactly what we want: look for
> > `pick` lines, skip any fixup/squash chains, and then insert the `exec`
> > line. Lather, rinse, repeat.
> > 
> > While at it, also add `exec` lines after `merge` commands, because they
> > are similar in spirit to `pick` commands: they add new commits.
> > 
> > Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> > ---
> >   sequencer.c              | 37 +++++++++++++++++++++++++++----------
> >   t/t3430-rebase-merges.sh |  2 +-
> >   2 files changed, 28 insertions(+), 11 deletions(-)
> > 
> > diff --git a/sequencer.c b/sequencer.c
> > index 31038472f..ed2e694ff 100644
> > --- a/sequencer.c
> > +++ b/sequencer.c
> > @@ -4244,10 +4244,9 @@ int sequencer_add_exec_commands(const char *commands)
> >   {
> >    const char *todo_file = rebase_path_todo();
> >    struct todo_list todo_list = TODO_LIST_INIT;
> > -	struct todo_item *item;
> >    struct strbuf *buf = &todo_list.buf;
> >    size_t offset = 0, commands_len = strlen(commands);
> > -	int i, first;
> > +	int i, insert;
> >   
> >    if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
> >   		return error(_("could not read '%s'."), todo_file);
> > @@ -4257,19 +4256,37 @@ int sequencer_add_exec_commands(const char
> > *commands)
> >    	return error(_("unusable todo list: '%s'"), todo_file);
> >    }
> >   -	first = 1;
> > -	/* insert <commands> before every pick except the first one */
> > -	for (item = todo_list.items, i = 0; i < todo_list.nr; i++, item++) {
> > -		if (item->command == TODO_PICK && !first) {
> > -			strbuf_insert(buf, item->offset_in_buf + offset,
> > -				      commands, commands_len);
> > +	/*
> > +	 * Insert <commands> after every pick. Here, fixup/squash chains
> > +	 * are considered part of the pick, so we insert the commands *after*
> > +	 * those chains if there are any.
> > +	 */
> > +	insert = -1;
> > +	for (i = 0; i < todo_list.nr; i++) {
> > +		enum todo_command command = todo_list.items[i].command;
> > +
> > +		if (insert >= 0) {
> > +			/* skip fixup/squash chains */
> > +			if (command == TODO_COMMENT)
> > +				continue;
> 
> insert is not updated so if the next command is not a fixup the exec
> line will be inserted before the comment.

> > +			else if (is_fixup(command)) {
> > +				insert = i + 1;
> > +				continue;
> > +			}
> > +			strbuf_insert(buf,
> > +				      todo_list.items[insert].offset_in_buf +
> > +				      offset, commands, commands_len);
> >   			offset += commands_len;
> > +			insert = -1;
> >   		}
> > -		first = 0;
> > +
> > +		if (command == TODO_PICK || command == TODO_MERGE)
> > +			insert = i + 1;
> >    }
> >   
> >   	/* append final <commands> */
> > -	strbuf_add(buf, commands, commands_len);
> > +	if (insert >= 0 || !offset)
> > +		strbuf_add(buf, commands, commands_len);
> 
> Having read your other message about this patch I think if you wanted to fix
> the position of the final exec in the case where the todo list ends with a
> comment you could do something like
> 
> 	if (insert >= 0)
> 		strbuf_insert(buf,
> 			      todo_list.items[insert].offset_in_buf +
> 			      offset, commands, commands_len);
> 	else
> 		strbuf_add(buf, commands, commands_len);