Method concat

src/repr/src/relation.rs:1152–1179

Concatenates a `RelationDesc` onto the end of this `RelationDesc`. # Panics Panics if either `self` or `other` have columns that were added at a [`RelationVersion`] other than [`RelationVersion::root`] or if any columns were dropped. TODO(parkmycar): Move this method to [`RelationDescBuilder`].

(mut self, other: Self)

    ///
    /// TODO(parkmycar): Move this method to [`RelationDescBuilder`].
    pub fn concat(mut self, other: Self) -> Self {
        let self_len = self.typ.column_types.len();

        for (typ, (_col_idx, meta)) in other.typ.column_types.into_iter().zip_eq(other.metadata) {
            assert_eq!(meta.added, RelationVersion::root());
            assert_none!(meta.dropped);

            let new_idx = self.typ.columns().len();
            let new_meta = ColumnMetadata {
                name: meta.name,
                typ_idx: new_idx,
                added: RelationVersion::root(),
                dropped: None,
            };

            self.typ.column_types.push(typ);
            let prev = self.metadata.insert(ColumnIndex(new_idx), new_meta);

            assert_eq!(self.metadata.len(), self.typ.columns().len());
            assert_none!(prev);
        }

        for k in other.typ.keys {
            let k = k.into_iter().map(|idx| idx + self_len).collect();
            self = self.with_key(k);
        }
        self
    }

    /// Adds a new key for the relation.
    pub fn with_key(mut self, indices: Vec<usize>) -> Self {