Re: [PATCH v2] sha1-file: remove OBJECT_INFO_SKIP_CACHED

> To follow up on Junio's hint in his review: callers can inject
> additional cached objects by using pretend_object_file.  Junio
> described how this would make sense as a mechanism for building
> the virtual ancestor object, but we don't do that.  In fact, the
> only caller is fake_working_tree_commit in "git blame", a read-only
> code path. *phew*
> 
> -- >8 --
> Subject: sha1-file: document how to use pretend_object_file
> [...]
> +/*
> + * Add an object file to the in-memory object store, without writing it
> + * to disk.
> + *
> + * Callers are responsible for calling write_object_file to record the
> + * object in persistent storage before writing any other new objects
> + * that reference it.
> + */
>  int pretend_object_file(void *, unsigned long, enum object_type,
>  			struct object_id *oid);
>