Re: [PATCH v6 14/16] rebase-interactive: rewrite edit_todo_list() to handle the initial edit

[Phillip Wood <phillip.wood@talktalk.net>]

Hi Alban

On 06/02/2019 21:11, Alban Gruin wrote:
> Hi Phillip,
> 
> I’ve just reread this message and have a couple of additionnal comments.
> 
> Le 01/02/2019 à 12:03, Phillip Wood a écrit :
>> Hi Alban
>>
>> This looks good apart from some missing error handling.
>>
>> On 29/01/2019 15:01, Alban Gruin wrote:
>>> edit_todo_list() is changed to work on a todo_list, and to handle the
>>> initial edition of the todo list (ie. making a backup of the todo
>>> list).
>>>
>>> It does not check for dropped commits yet, as todo_list_check() does not
>>> take the commits that have already been processed by the rebase (ie. the
>>> todo list is edited in the middle of a rebase session).
>>>
>>> Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
>>> ---
>>>   builtin/rebase--interactive.c | 24 +++++++++++++++++-
>>>   rebase-interactive.c          | 48 ++++++++++++++++++-----------------
>>>   rebase-interactive.h          |  4 ++-
>>>   sequencer.c                   |  3 +--
>>>   sequencer.h                   |  1 +
>>>   5 files changed, 53 insertions(+), 27 deletions(-)
>>>
>>> diff --git a/builtin/rebase--interactive.c
>>> b/builtin/rebase--interactive.c
>>> index 2dbf8fc08b..645ac587f7 100644
>>> --- a/builtin/rebase--interactive.c
>>> +++ b/builtin/rebase--interactive.c
>>> @@ -13,6 +13,28 @@ static GIT_PATH_FUNC(path_state_dir, "rebase-merge/")
>>>   static GIT_PATH_FUNC(path_squash_onto, "rebase-merge/squash-onto")
>>>   static GIT_PATH_FUNC(path_interactive, "rebase-merge/interactive")
>>>   +static int edit_todo_file(unsigned flags)
>>> +{
>>> +    const char *todo_file = rebase_path_todo();
>>> +    struct todo_list todo_list = TODO_LIST_INIT,
>>> +        new_todo = TODO_LIST_INIT;
>>> +
>>> +    if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
>>> +        return error_errno(_("could not read '%s'."), todo_file);
>>> +
>>> +    strbuf_stripspace(&todo_list.buf, 1);
>>> +    if (!edit_todo_list(the_repository, &todo_list,
>>> +                &new_todo, NULL, NULL, flags) &&
>>> +        todo_list_write_to_file(the_repository, &new_todo, todo_file,
>>> NULL, NULL,
>>> +                    -1, flags & ~(TODO_LIST_SHORTEN_IDS)) < 0)
>>> +        return error_errno(_("could not write '%s'"), todo_file);
>>
>> If edit_todo_list() fails then the function returns 0. I think you need
>> to do
>>
>> if (edit_todo_list() || todo_list_write_file())
>>     return error...
>>
>> todo_list_write_file() forwards the return value of write_message()
>> which is 0/-1 so there is no need for the '< 0'
>>
> 
> With your proposed condition, if edit_todo_list() fails, the error
> "could not write '%s'" will be shown, if I’m not mistaken.

Yes, you're right but as edit_todo_list() will have already printed an
error I decided it didn't matter too much, but it would be better to
avoid it as you suggest.

> But in my
> version, if edit_todo_list() fails, the return value is 0.  Perhaps I
> should write something like this instead:
> 
>     int res = 0;
>     …
>     res = edit_todo_list();
>     if (!res && todo_list_write_to_file())
>         return error;

If you did
	ret = error...;
instead then we always free the todo lists before exiting the function.

>     …
>     return res;
>>> +
>>> +    todo_list_release(&todo_list);
>>> +    todo_list_release(&new_todo);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>>   static int get_revision_ranges(const char *upstream, const char *onto,
>>>                      const char **head_hash,
>>>                      char **revisions, char **shortrevisions)
>>> @@ -242,7 +264,7 @@ int cmd_rebase__interactive(int argc, const char
>>> **argv, const char *prefix)
>>>           break;
>>>       }
>>>       case EDIT_TODO:
>>> -        ret = edit_todo_list(the_repository, flags);
>>> +        ret = edit_todo_file(flags);
>>>           break;
>>>       case SHOW_CURRENT_PATCH: {
>>>           struct child_process cmd = CHILD_PROCESS_INIT;
>>> diff --git a/rebase-interactive.c b/rebase-interactive.c
>>> index 807f8370db..3301efbe52 100644
>>> --- a/rebase-interactive.c
>>> +++ b/rebase-interactive.c
>>> @@ -87,35 +87,37 @@ void append_todo_help(unsigned keep_empty, int
>>> command_count,
>>>       }
>>>   }
>>>   -int edit_todo_list(struct repository *r, unsigned flags)
>>> +int edit_todo_list(struct repository *r, struct todo_list *todo_list,
>>> +           struct todo_list *new_todo, const char *shortrevisions,
>>> +           const char *shortonto, unsigned flags)
>>>   {
>>>       const char *todo_file = rebase_path_todo();
>>> -    struct todo_list todo_list = TODO_LIST_INIT;
>>> -    int res = 0;
>>> -
>>> -    if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
>>> -        return error_errno(_("could not read '%s'."), todo_file);
>>> -
>>> -    strbuf_stripspace(&todo_list.buf, 1);
>>> -    todo_list_parse_insn_buffer(r, todo_list.buf.buf, &todo_list);
>>> -    if (todo_list_write_to_file(r, &todo_list, todo_file, NULL, NULL,
>>> -1,
>>> -                    flags | TODO_LIST_SHORTEN_IDS |
>>> TODO_LIST_APPEND_TODO_HELP)) {
>>> -        todo_list_release(&todo_list);
>>> -        return -1;
>>> +    unsigned initial = shortrevisions && shortonto;
>>> +
>>> +    if (initial) {
>>> +        todo_list_write_to_file(r, todo_list, todo_file,
>>> shortrevisions, shortonto,
>>> +                    -1, flags | TODO_LIST_SHORTEN_IDS |
>>> TODO_LIST_APPEND_TODO_HELP);
>>
>> This has lost the error handling when we cannot write the file
>>
>>> +
>>> +        if (copy_file(rebase_path_todo_backup(), todo_file, 0666))
>>> +            return error(_("could not copy '%s' to '%s'."), todo_file,
>>> +                     rebase_path_todo_backup());
>>> +    } else {
>>> +        todo_list_parse_insn_buffer(r, todo_list->buf.buf, todo_list);
>>> +        todo_list_write_to_file(r, todo_list, todo_file, NULL, NULL, -1,
>>> +                    flags | TODO_LIST_SHORTEN_IDS |
>>> TODO_LIST_APPEND_TODO_HELP);
>>
>> error handling again
>>
> 
> I agree for todo_list_write_to_file(), but todo_list_parse_insn_buffer()
> already shows an error, and here it should not return -- we want to edit
> the todo list to remove an error, but git would fail because the todo
> list has an error.

Ah yes, that is what the original was doing


Best Wishes

Phillip

> 
> -- Alban
>