SeaQL/sea-orm · error

Failed to get json array

Error message

Failed to get json array

What it means

For JSON[]/JSONB[] columns, ProxyRow calls row.try_get::<Option<Vec<serde_json::Value>>, _> and .expect("Failed to get json array") panics on sqlx decode failure. The value claimed to be a JSON array could not be decoded as Vec<serde_json::Value> — usually it is not actually an array of json on the wire, or an element cannot be represented in serde_json.

Source

Thrown at src/driver/sqlx_postgres.rs:666

                                            .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(),
                                    )
                                }),
                        ),

                        #[cfg(feature = "with-ipnetwork")]
                        "INET" | "CIDR" => Value::IpNetwork(
                            row.try_get::<Option<ipnetwork::IpNetwork>, _>(c.ordinal())
                                .expect("Failed to get ip address"),
                        ),
                        #[cfg(feature = "with-ipnetwork")]
                        "INET[]" | "CIDR[]" => Value::Array(
                            sea_query::ArrayType::IpNetwork,
                            row.try_get::<Option<Vec<ipnetwork::IpNetwork>>, _>(c.ordinal())

View on GitHub (pinned to e29bcd1b41)

Solutions

1. Confirm the column is truly jsonb[] / json[] (udt_name like _jsonb) and normalize with ALTER ... TYPE jsonb[] USING col::jsonb[].
2. Cast in SQL: SELECT my_col::jsonb[] AS my_col.
3. Enable both with-json and the relevant array feature (postgres-array or json-array) in sea-orm features.
4. Replace .expect with mapped DbErr to get actionable diagnostics.

Example fix

// before
.expect("Failed to get json array")
// 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("tags").fetch_one(&pool).await?;
assert!(udt.0 == "_json" || udt.0 == "_jsonb", "not a json array: {}", udt.0);

fn is_json_array(udt_name: &str) -> bool { matches!(udt_name, "_json" | "_jsonb") }

When it happens

Trigger: A query selecting a column whose type name is "JSON[]"/"JSONB[]" but whose value is a scalar json, a 2-D array, or a domain-over-array; requires the json-array or postgres-array feature for the arm to compile.

Common situations: Schema drift where a text[] holds JSON strings; reading from a view or FDW that reports the wrong array element type; feature flags changed (json-array removed) so the column now falls into a different decode path.

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 array
• Failed to get oid array
• Failed to get json
• Failed to get ip address array
• Failed to get mac address array

AI-assisted analysis of SeaQL/sea-orm@e29bcd1b41 (2026-09-10). Data as JSON: /api/errors/5c15f8502580ac63. Report an issue: GitHub.