SeaQL/sea-orm · error

Failed to get json

Error message

Failed to get json

What it means

ProxyRow decodes Postgres JSON/JSONB columns into serde_json::Value and .expect("Failed to get json") panics on sqlx decode failure. Since the target is Option<serde_json::Value>, NULL is handled; the panic means the value's wire type isn't json/jsonb as sqlx sees it, or the value contains something serde_json cannot represent (e.g. NaN/Infinity produced by non-standard serializers).

Source

Thrown at src/driver/sqlx_postgres.rs:656

                        }
                        #[cfg(feature = "postgres-array")]
                        "OID[]" => Value::Array(
                            sea_query::ArrayType::BigInt,
                            row.try_get::<Option<Vec<i64>>, _>(c.ordinal())
                                .expect("Failed to get oid array")
                                .map(|vals| {
                                    Box::new(
                                        vals.into_iter()
                                            .map(|val| Value::BigInt(Some(val)))
                                            .collect(),
                                    )
                                }),
                        ),

                        #[cfg(feature = "with-json")]
                        "JSON" | "JSONB" => Value::Json(
                            row.try_get::<Option<serde_json::Value>, _>(c.ordinal())
                                .expect("Failed to get json")
                                .map(Box::new),
                        ),
                        #[cfg(all(
                            feature = "with-json",
                            any(feature = "json-array", feature = "postgres-array")
                        ))]
                        "JSON[]" | "JSONB[]" => Value::Array(
                            sea_query::ArrayType::Json,
                            row.try_get::<Option<Vec<serde_json::Value>>, _>(c.ordinal())
                                .expect("Failed to get json array")
                                .map(|vals| {
                                    Box::new(
                                        vals.into_iter()
                                            .map(|val| Value::Json(Some(Box::new(val))))
                                            .collect(),
                                    )
                                }),
                        ),

View on GitHub (pinned to e29bcd1b41)

Solutions

1. Check the column's real type (udt_name should be json or _/jsonb) and fix the schema with ALTER TABLE ... ALTER COLUMN ... TYPE jsonb USING col::jsonb.
2. Cast in the query: SELECT my_col::jsonb AS my_col.
3. Ensure the with-json feature (and compatible serde_json version) is enabled on both sea-orm and the sqlx dependency.
4. In driver code, replace .expect with error propagation (DbErr::TryIntoError) to surface which ordinal failed.

Example fix

// before
.expect("Failed to get json")
// after
.map_err(|e| DbErr::TryIntoError { value_type: "json".into(), source: e.into() })?

let udt: (String,) = sqlx::query_as(
    "SELECT udt_name FROM information_schema.columns WHERE table_name=$1 AND column_name=$2",
)
.bind("my_table").bind("payload").fetch_one(&pool).await?;
assert!(matches!(udt.0.as_str(), "json" | "jsonb"), "not a json column: {}", udt.0);

fn is_json_type(udt_name: &str) -> bool { matches!(udt_name, "json" | "jsonb") }

When it happens

Trigger: Selecting a column named "JSON"/"JSONB" by type when the server actually returns a different wire format (e.g. a domain over jsonb in an older Postgres wire type, or a text column that the driver misclassifies), or with the with-json feature enabled while the value exceeds sqlx's decoding limits.

Common situations: Columns created via an ORM migration that ended up as text instead of jsonb; reading a view whose output type differs from the base table; Postgres extensions returning json-compatible types under a different OID.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Failed to get uuid
• Failed to get uuid array
• Failed to get oid
• Failed to get oid array
• Failed to get json array

AI-assisted analysis of SeaQL/sea-orm@e29bcd1b41 (2026-09-10). Data as JSON: /api/errors/ef993d9ea5b70ab4. Report an issue: GitHub.