use crate::{compound, loose, pack};use git_object::borrowed; /// Returned by [`compound::Db::locate()`]#[derive(thiserror::Error, Debug)]#[allow(missing_docs)]pub enum Error {    #[error("An error occurred while obtaining an object from the loose object store")]    Loose(#[from] loose::db::locate::Error),    #[error("An error occurred while obtaining an object from the packed object store")]    Pack(#[from] pack::data::decode::Error),} impl compound::Db {    /// Find an object as identified by [`id`][borrowed::Id] and store its data in full in the provided `buffer`.    /// This will search the object in all contained object databases.    pub fn locate<'a>(        &self,        id: borrowed::Id<'_>,        buffer: &'a mut Vec<u8>,    ) -> Option<Result<compound::Object<'a>, Error>> {        for alternate in &self.alternates {            // See 8c5bd095539042d7db0e611460803cdbf172beb0 for a commit that adds polonius and makes the proper version compile.            // See https://stackoverflow.com/questions/63906425/nll-limitation-how-to-work-around-cannot-borrow-buf-as-mutable-more-than?noredirect=1#comment113007288_63906425            // More see below! Of course we don't want to do the lookup twice… but have to until this is fixed or we compile nightly.            if alternate.locate(id, buffer).is_some() {                return alternate.locate(id, buffer);            }        }        for pack in &self.packs {            // See 8c5bd095539042d7db0e611460803cdbf172beb0 for a commit that adds polonius and makes the proper version compile.            // See https://stackoverflow.com/questions/63906425/nll-limitation-how-to-work-around-cannot-borrow-buf-as-mutable-more-than?noredirect=1#comment113007288_63906425            // The underlying issue is described here https://github.com/rust-lang/rust/issues/45402,            // Once Polonius becomes a thing AND is not too slow, we must remove this double-lookup to become something like this:            // if let Some(object) = if pack.locate(id, buffer, &mut pack::cache::DecodeEntryNoop) {…}            if pack.locate(id, buffer, &mut pack::cache::Noop).is_some() {                let object = pack.locate(id, buffer, &mut pack::cache::Noop).unwrap();                return Some(object.map(compound::Object::Borrowed).map_err(Into::into));            }        }        self.loose            .locate(id)            .map(|object| object.map(compound::Object::Loose).map_err(Into::into))    }}