Repository: launchbadge/sqlx
File: sqlx-postgres/src/bind_iter.rs (Rust)

Code before:
            .and_then(Encode::produces)
            .unwrap_or_else(T::type_info);

        buf.extend(&1_i32.to_be_bytes()); // number of dimensions
        buf.extend(&0_i32.to_be_bytes()); // flags

        match type_info.0 {
            PgType::DeclareWithName(name) => buf.patch_type_by_name(&name),
            PgType::DeclareArrayOf(array) => buf.patch_array_type(array),

            ty => {
                buf.extend(&ty.oid().0.to_be_bytes());
            }
        }

        let len_start = buf.len();
        buf.extend(0_i32.to_be_bytes()); // len (unknown so far)
        buf.extend(1_i32.to_be_bytes()); // lower bound

        match first {
            Some(first) => buf.encode(first)?,
            None => return Ok(IsNull::No),
        }

        let mut count = 1_i32;
        const MAX: usize = i32::MAX as usize;

        for value in (&mut iter).take(MAX) {
            buf.encode(value)?;
            count += 1;
        }

        const OVERFLOW: usize = MAX + 1;
        if iter.next().is_some() {
            return Err(format!("encoded iterator is too large for Postgres: {OVERFLOW}").into());
        }

        // set the length now that we know what it is.
        buf[len_start..(len_start + 4)].copy_from_slice(count.to_be_bytes().as_slice());

        Ok(IsNull::No)
    }
}

impl<'q, T, I> Encode<'q, Postgres> for PgBindIter<I>
where
    T: Type<Postgres> + Encode<'q, Postgres>,
    // Clone is required for the encode_by_ref call since we can't iterate with a shared reference
    I: Iterator<Item = T> + Clone,
{
    fn encode_by_ref(

Review comment (suggestion):
This looks like an oversight. We've already written 1 item at this point.

```suggestion
        const MAX: usize = i32::MAX as usize - 1;
```

Code after:
///     .execute(&mut conn)
///     .await?;
///
/// # Ok(())
/// # }
/// ```
pub trait PgBindIterExt: Iterator + Sized {
    fn bind_iter(self) -> PgBindIter<Self>;
}

impl<I: Iterator + Sized> PgBindIterExt for I {
    fn bind_iter(self) -> PgBindIter<I> {
        PgBindIter(Cell::new(Some(self)))
    }
}

impl<I> Type<Postgres> for PgBindIter<I>
where
    I: Iterator,
    <I as Iterator>::Item: Type<Postgres> + PgHasArrayType,
{
    fn type_info() -> <Postgres as Database>::TypeInfo {
        <I as Iterator>::Item::array_type_info()
    }
    fn compatible(ty: &PgTypeInfo) -> bool {
        <I as Iterator>::Item::array_compatible(ty)
    }
}

impl<'q, I> PgBindIter<I>
where
    I: Iterator,
    <I as Iterator>::Item: Type<Postgres> + Encode<'q, Postgres>,
{
    fn encode_inner(
        // need ownership to iterate
        mut iter: I,
        buf: &mut PgArgumentBuffer,
    ) -> Result<IsNull, BoxDynError> {
        let lower_size_hint = iter.size_hint().0;
        let first = iter.next();
        let type_info = first
            .as_ref()
            .and_then(Encode::produces)
            .unwrap_or_else(<I as Iterator>::Item::type_info);

        buf.extend(&1_i32.to_be_bytes()); // number of dimensions
        buf.extend(&0_i32.to_be_bytes()); // flags

        match type_info.0 {
            PgType::DeclareWithName(name) => buf.patch_type_by_name(&name),