Re: [PATCH 2/3] log-tree: make name_decoration hash static

> In the previous commit, we made add_name_decoration global
> so that adders would not have to access the hash directly.
> We now make the hash itself static so that callers _have_ to
> add through our function, making sure that all additions go
> through a single point.  To do this, we have to add one more
> accessor function: a way to lookup entries in the hash.
>
> Since the only caller doesn't actually look at the returned
> value, but rather only asks whether there is a decoration or
> not, we could provide only a boolean "has_name_decoration".
> That would allow us to make "struct name_decoration" local
> to log-tree, as well.
>
> However, it's unlikely to cause any maintainability harm
> making the actual data public, and this interface is more
> flexible if we need to look at decorations from other parts
> of the code in the future.