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

[Alban Gruin <alban.gruin@gmail.com>]

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.  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;
    …
    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.

-- Alban