round-trip serialization fails

[doug-q]

As evidenced in #948 our serialization is not currently round-tripping as one would expect. There seem to be two flavours of failure:

``` ---- hugr::views::tests::mermaid_string::case_2_cfg stdout ---- thread 'hugr::views::tests::mermaid_string::case_2_cfg' panicked at hugr/src/hugr/serialize.rs:327:34: called `Result::unwrap()` on an `Err` value: Error("Cannot connect an edge without port offset to node Node(1) with operation type DataflowBlock(DataflowBlock { inputs: TypeRow { types: [Type(Extension(CustomType { extension: IdentList(\"prelude\"), id: \"usize\", args: [], bound: Eq }), Eq)] }, other_outputs: TypeRow { types: [] }, sum_rows: [TypeRow { types: [Type(Extension(CustomType { extension: IdentList(\"prelude\"), id: \"usize\", args: [], bound: Eq }), Eq)] }, TypeRow { types: [Type(Extension(CustomType { extension: IdentList(\"prelude\"), id: \"usize\", args: [], bound: Eq }), Eq)] }], extension_delta: ExtensionSet({}) }).", line: 0, column: 0) ```

and

``` ---- ops::constant::test::test_sum stdout ---- thread 'ops::constant::test::test_sum' panicked at hugr/src/hugr/serialize.rs:353:13: assertion `left == right` failed left: Const(Sum { tag: 0, values: [Extension { e: ExtensionConst(CustomTestValue(CustomType { extension: IdentList("prelude"), id: "usize", args: [], bound: Eq })) }, Extension { e: ExtensionConst(CustomSerialized { typ: Type(Extension(CustomType { extension: IdentList("arithmetic.float.types"), id: "float64", args: [], bound: Copyable }), Copyable), value: Number(5.1), extensions: ExtensionSet({IdentList("arithmetic.float.types")}) }) }], sum_type: General { rows: [TypeRow { types: [Type(Extension(CustomType { extension: IdentList("prelude"), id: "usize", args: [], bound: Eq }), Eq), Type(Extension(CustomType { extension: IdentList("arithmetic.float.types"), id: "float64", args: [], bound: Copyable }), Copyable)] }, TypeRow { types: [] }] } }) right: Const(Sum { tag: 0, values: [Extension { e: ExtensionConst(CustomTestValue(CustomType { extension: IdentList("prelude"), id: "usize", args: [], bound: Eq })) }, Extension { e: ExtensionConst(CustomSerialized { typ: Type(Extension(CustomType { extension: IdentList("arithmetic.float.types"), id: "float64", args: [], bound: Copyable }), Copyable), value: Number(5.1), extensions: ExtensionSet({IdentList("arithmetic.float.types")}) }) }], sum_type: General { rows: [TypeRow { types: [Type(Extension(CustomType { extension: IdentList("prelude"), id: "usize", args: [], bound: Eq }), Eq), Type(Extension(CustomType { extension: IdentList("arithmetic.float.types"), id: "float64", args: [], bound: Copyable }), Copyable)] }, TypeRow { types: [] }] } }) ```

I have confirmed that these failures are present back to v0.1

[doug-q]

The second failure class is caused by missing equals_const for CustomTestValue, I've pushed a fix to #948

[doug-q]

The first failure is caused by not accounting properly for ControlFlow edges. See OpType::other_port and consider a DataflowBlock with a number of out edges != 1

[aborgna-q]

I've pushed a fix to #947

I think you meant #948

[doug-q]

Fixed by #1005 #968