If I insert an `Option<sqlx::types::Json<Struct>>` sqlx writes the text `null` in DB instead of mark that field as `NULL`

[frederikhors]

I thought the problem was me and my code and so I tried to reproduce the problem with your code in examples.

I only made minor changes by adding an Option<> to simulate my real problem.

- async fn add_person(pool: &PgPool, person: Person) -> anyhow::Result<i64> {
+ async fn add_person(pool: &PgPool, person: Option<Person>) -> anyhow::Result<i64> {

and in migrations:

- person JSONB NOT NULL
+ person JSONB

If I run it it is saved in the DB:

and instead I expect this:

Where am I doing wrong?

Minimal Reproduction

https://github.com/frederikhors/iss-sqlx-option-null

Info

• SQLx version: "0.7.4"
• SQLx features enabled: "macros", "postgres", "runtime-tokio", "chrono", "uuid"
• Database server and version: Postgres 16
• Operating system: Windows
• rustc --version: rustc 1.79.0 (129f3b996 2024-06-10)

I think we can also close these issues after this one (maybe):

1. https://github.com/launchbadge/sqlx/issues/2438

2. https://github.com/launchbadge/sqlx/issues/2849

[frederikhors]

My fault: https://users.rust-lang.org/t/if-i-insert-an-option-sqlx-json-struct-sqlx-writes-the-text-null-in-db-instead-of-mark-that-field-as-null/113078/2