[AVRO-3901] [Rust] Better serde union support

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.11.3
• Fix Version/s: 1.12.0, 1.11.4
• Component/s: rust
• Labels: pull-request-available
• Assignee: Martin Tzvetanov Grigorov
• Reporter: Simon Gittins
• Created: 12/Nov/23 22:23
• Updated: 15/Nov/23 13:58
• Resolved: 14/Nov/23 13:42

Description

(Full code examples in unit tests of attached PR).

Want to be able to serde to/from an enum containing structs for a union schema containing record(s):

{
  "name": "C",
  "type": "record",
  "fields": [
...
    {"name": "field_union", "type": ["A", "B"]},
...
  ]
}

With code like:

struct A {...}
struct B {...}

#[serde(untagged)]
enum UnionAB { A(A), B(B)}

struct C {
  ...
  field_union: UnionAB,
  ...
}

Likewise, want to be able to serde where the schema includes null:

{
  "name": "E",
  "type": "record",
  "fields": [
    ...
    {"name": "field_union", "type": ["A", "null", "B"]},
    ...
  ]
}

#[serde(untagged)]
enum UnionANoneB {
    A(A),
    None,
    B(B),
}

Issue Links

• links to: GitHub Pull Request #2583