> +--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!
