Re: [PATCH v3] attr: teach "--attr-source=<tree>" global option to "git"

>>       +--attr-source=<tree-ish>::
>>      -+ Read gitattributes from <tree-ish> instead of the worktree.
>>      ++ Read gitattributes from <tree-ish> instead of the worktree. See
>>      ++ linkgit:gitrevisions[7].
>
> I think it's more sensible to link to gitattributes(5) instead of
> gitrevisions(7)

>
>> +static const char *default_attr_source_tree_object_name;
>> +
>> +void set_git_attr_source(const char *tree_object_name)
>> +{
>> +       default_attr_source_tree_object_name = xstrdup(tree_object_name);
>> +}
>> +
>> +
>
> One empty line is enough here.

>
>> +static void compute_default_attr_source(struct object_id *attr_source)
>> +{
>> +       int from_env = 0;
>> +
>> +       if (!default_attr_source_tree_object_name) {
>> +               default_attr_source_tree_object_name = getenv(GIT_ATTR_SOURCE);
>> +               from_env = 1;
>> +       }
>> +
>> +       if (!default_attr_source_tree_object_name || !is_null_oid(attr_source))
>> +               return;
>> +
>> +       if (repo_get_oid_treeish(the_repository, default_attr_source_tree_object_name, attr_source)) {
>> +               if (from_env)
>> +                       die(_("bad --attr-source object"));
>> +               else
>> +                       die(_("bad GIT_ATTR_SOURCE"));
>
> I think it would be better to have just the following instead of the 4
> lines above:
>
> die(_("invalid tree object from --attr-source flag or GIT_ATTR_SOURCE
> env variable"));
>
> as a bad GIT_ATTR_SOURCE in a subprocess could come from a bad
> --attr-source in the main process.
>
> And this way the from_env variable is not needed.

>
>> +       }
>> +}
>
> The rest looks good to me, thanks!