jackc/pgx · error

invalid array, expected

Error message

invalid array, expected '{' got %v

What it means

After consuming the optional '[dims]=' prefix (or immediately for a plain literal), parseUntypedTextArray requires the array body to open with '{'. A value that is not a text array at all (e.g. a scalar or a bracket-only string) fails here.

Solutions

1. Ensure the value being scanned is a PostgreSQL array text literal like '{1,2,3}'
2. Wrap scalar values in braces before treating them as arrays
3. Check that the column type and the Go scan target actually match (array vs scalar)

When it happens

Trigger: Thrown at pgtype/array.go:170 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of jackc/pgx@ec1a0befd2 (2026-08-04). Data as JSON: /api/errors/7a524d833113af14. Report an issue: GitHub.

Appendix: source

Thrown at pgtype/array.go:170

			if err != nil {
				return nil, fmt.Errorf("invalid array: %w", err)
			}

			if r != ']' {
				return nil, fmt.Errorf("invalid array, expected ']' got %v", r)
			}

			explicitDimensions = append(explicitDimensions, ArrayDimension{LowerBound: lower, Length: upper - lower + 1})
		}

		r, _, err = buf.ReadRune()
		if err != nil {
			return nil, fmt.Errorf("invalid array: %w", err)
		}
	}

	if r != '{' {
		return nil, fmt.Errorf("invalid array, expected '{' got %v", r)
	}

	implicitDimensions := []ArrayDimension{{LowerBound: 1, Length: 0}}

	// Consume all initial opening brackets. This provides number of dimensions.
	for {
		r, _, err = buf.ReadRune()
		if err != nil {
			return nil, fmt.Errorf("invalid array: %w", err)
		}

		if r == '{' {
			implicitDimensions[len(implicitDimensions)-1].Length = 1
			implicitDimensions = append(implicitDimensions, ArrayDimension{LowerBound: 1})
		} else {
			buf.UnreadRune()
			break
		}

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