Re: [PATCH 2/2] rust: alloc: add `Vec::dec_len`

[Alice Ryhl <aliceryhl@google.com>]

On Mon, Mar 17, 2025 at 11:47:50AM +0000, Alice Ryhl wrote:
> On Mon, Mar 17, 2025 at 07:34:44AM -0400, Tamir Duberstein wrote:
> > On Mon, Mar 17, 2025 at 6:04 AM Benno Lossin <benno.lossin@proton.me> wrote:
> > >
> > > On Sun Mar 16, 2025 at 11:32 PM CET, Tamir Duberstein wrote:
> > > > Add `Vec::dec_len` that reduces the length of the receiver. This method
> > > > is intended to be used from methods that remove elements from `Vec` such
> > > > as `truncate`, `pop`, `remove`, and others. This method is intentionally
> > > > not `pub`.
> > >
> > > I think it should be `pub`. Otherwise we're loosing functionality
> > > compared to now. If one decides to give the raw pointer to some C API
> > > that takes ownership of the pointer, then I want them to be able to call
> > > `dec_len` manually.
> > 
> > This is premature. It is trivial to make this function pub when the need arises.
> 
> Normally I'd agree with Benno, but in this case I think having it
> private is preferable. The function is safe, so it's too easy for
> end-users to confuse it with truncate.

Thinking more about this ... I think we should have `set_len` and
`inc_len` instead. That way, both methods are unsafe so people will not
accidentally use `set_len` when they meant to use `truncate`.

Alice