Hi Phillip,
On Mon, 6 Aug 2018, Phillip Wood wrote:
> On 06/08/18 10:52, Johannes Schindelin via GitGitGadget wrote:
> >
> > From: Johannes Schindelin <johannes.schindelin@xxxxxx>
> >
> > 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@xxxxxx>
> > ---
> > 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.
Yes, this is very much on purpose. Take this todo list, for example:
pick 123456 this patch
# pick 987654 this was an empty commit
You definitely do not want the `exec` to appear after that commented-out
empty commit.
> > + 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);
That does not really work, as `insert` can point *after* the last line, in
which case `todo_list.items[insert]` is undefined (and in the worst case,
causes a segmentation fault).
> I'm not sure it matters that much though
Well, it does matter to me. After having this in the back of my head, and
after your comment, I think it *is* worth the additional complexity after
all.
Will come up with a new iteration.
Ciao,
Dscho
