Re: [PATCH v2 09/18] unpack-trees: add a new update_sparsity() function

> > +     for (i = 0; i < o->src_index->cache_nr; i++) {
> > +             struct cache_entry *ce = o->src_index->cache[i];
> > +
> > +             if (apply_sparse_checkout(o->src_index, ce, o))
> > +                     ret = UPDATE_SPARSITY_WARNINGS;
> > +
> > +             if (!ce_skip_worktree(ce))
> > +                     empty_worktree = 0;
> > +
>
> nit: extra whitespace-only line

> > +     }
> > +
> > +     /*
> > +      * Sparse checkout is meant to narrow down checkout area
> > +      * but it does not make sense to narrow down to empty working
> > +      * tree. This is usually a mistake in sparse checkout rules.
> > +      * Do not allow users to do that.
> > +      */
> > +     if (o->src_index->cache_nr && empty_worktree) {
> > +             unpack_failed(o, "Sparse checkout leaves no entry on working directory");
> > +             ret = UPDATE_SPARSITY_INDEX_UPDATE_FAILURES;
> > +             goto done;
> > +     }
> > +
> > +skip_sparse_checkout:
> > +     if (check_updates(o, o->src_index))
> > +             ret = UPDATE_SPARSITY_WORKTREE_UPDATE_FAILURES;
> > +
> > +done:
> > +     display_error_msgs(o);
> > +     o->show_all_errors = old_show_all_errors;
> > +     if (free_pattern_list)
> > +             clear_pattern_list(&pl);
> > +     trace_performance_leave("update_sparsity");
> > +     return ret;
> > +}
> > +
> >  /* Here come the merge functions */
> >
> >  static int reject_merge(const struct cache_entry *ce,
> > diff --git a/unpack-trees.h b/unpack-trees.h
> > index d3516267f36..2c5d54cae9f 100644
> > --- a/unpack-trees.h
> > +++ b/unpack-trees.h
> > @@ -28,6 +28,13 @@ enum unpack_trees_error_types {
> >       NB_UNPACK_TREES_ERROR_TYPES
> >  };
> >
> > +enum update_sparsity_result {
> > +     UPDATE_SPARSITY_SUCCESS = 0,
> > +     UPDATE_SPARSITY_WARNINGS = 1,
> > +     UPDATE_SPARSITY_INDEX_UPDATE_FAILURES = -1,
> > +     UPDATE_SPARSITY_WORKTREE_UPDATE_FAILURES = -2
> > +};
> > +
>
> Is there a reason this isn't located just before
> update_sparsity()?

> >  /*
> >   * Sets the list of user-friendly error messages to be used by the
> >   * command "cmd" (either merge or checkout), and show_all_errors to 1.
> > @@ -88,6 +95,8 @@ struct unpack_trees_options {
> >  int unpack_trees(unsigned n, struct tree_desc *t,
> >                struct unpack_trees_options *options);
> >
> > +int update_sparsity(struct unpack_trees_options *options);
> > +
>
> This appears to not use the enum as it should.