Re: [PATCH/RFC/GSoC 05/17] rebase-options: implement rebase_options_load() and rebase_options_save()

>>
>> How is this specific to the state file? All it does is create the
>> leading directory
>> if it doesn't exist? (So I'd expect file_exists(concat(dir, file)) to
>> have the same
>> result without actually creating the directory if it doesn't exist as
>> a side effect?
>
> I don't quite understand, AFAIK mkpath() does not create any
> directories as a side-effect. And yes, I just wanted a short way to
> say file_exists(concat(dir, file)) or file_exists(mkpath("%s/%s", dir,
> file)) without cluttering up the code.

>
>> If the dir doesn't exist it can be created in rebase_options_load explicitly?
>
> I don't intend to create any directories if they do not exist.
>
>>> +
>>> +static int read_state_file(struct strbuf *sb, const char *dir, const char *file)
>>> +{
>>> +       const char *path = mkpath("%s/%s", dir, file);
>>> +       strbuf_reset(sb);
>>> +       if (strbuf_read_file(sb, path, 0) >= 0)
>>> +               return sb->len;
>>> +       else
>>> +               return error(_("could not read '%s'"), path);
>>> +}
>>> +
>>> +int rebase_options_load(struct rebase_options *opts, const char *dir)
>>> +{
>>> +       struct strbuf sb = STRBUF_INIT;
>>> +       const char *filename;
>>> +
>>> +       /* opts->orig_refname */
>>> +       if (read_state_file(&sb, dir, "head-name") < 0)
>>> +               return -1;
>>> +       strbuf_trim(&sb);
>>> +       if (starts_with(sb.buf, "refs/heads/"))
>>> +               opts->orig_refname = strbuf_detach(&sb, NULL);
>>> +       else if (!strcmp(sb.buf, "detached HEAD"))
>>> +               opts->orig_refname = NULL;
>>> +       else
>>> +               return error(_("could not parse %s"), mkpath("%s/%s", dir, "head-name"));
>>> +
>>> +       /* opts->onto */
>>> +       if (read_state_file(&sb, dir, "onto") < 0)
>>> +               return -1;
>>> +       strbuf_trim(&sb);
>>> +       if (get_oid_hex(sb.buf, &opts->onto) < 0)
>>> +               return error(_("could not parse %s"), mkpath("%s/%s", dir, "onto"));
>>> +
>>> +       /*
>>> +        * We always write to orig-head, but interactive rebase used to write
>>> +        * to head. Fall back to reading from head to cover for the case that
>>> +        * the user upgraded git with an ongoing interactive rebase.
>>> +        */
>>> +       filename = state_file_exists(dir, "orig-head") ? "orig-head" : "head";
>>> +       if (read_state_file(&sb, dir, filename) < 0)
>>> +               return -1;
>>
>> So from here on we always use "orig-head" instead of "head" for
>> interactive rebase.
>> Would people ever rely on the (internal) file name and have e.g.
>> scripts which operate
>> on the "head" file ?
>
> This backwards-compatibility code is just a straight port from the
> code in git-rebase.sh.
>
> The usage of orig-head has been around since 2011 with 84df456
> (rebase: extract code for writing basic state, 2011-02-06), so I guess
> if people had issues with it, it would have been reported.