jackc/pgx · error

cannot convert to Line

Error message

cannot convert %v to Line

What it means

Line.Set is the catch-all conversion path for building a pgtype.Line from arbitrary Go values, but no conversions are implemented — every non-supported input falls through to this unconditional error naming the source type. It exists to satisfy the Set interface contract while signaling that Line supports no direct Set conversions.

Solutions

1. Assign the struct fields directly: line.A, line.B, line.C, line.Valid
2. Construct a Line literal (Line{A: 1, B: 2, C: 3, Valid: true}) instead of calling Set
3. Use Scan with the textual representation for string sources

When it happens

Trigger: Thrown at pgtype/line.go:38 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/6282a69f5de62bee. Report an issue: GitHub.

Appendix: source

Thrown at pgtype/line.go:38

type Line struct {
	A, B, C float64
	Valid   bool
}

// ScanLine implements the [LineScanner] interface.
func (line *Line) ScanLine(v Line) error {
	*line = v
	return nil
}

// LineValue implements the [LineValuer] interface.
func (line Line) LineValue() (Line, error) {
	return line, nil
}

func (line *Line) Set(src any) error {
	return fmt.Errorf("cannot convert %v to Line", src)
}

// Scan implements the [database/sql.Scanner] interface.
func (line *Line) Scan(src any) error {
	if src == nil {
		*line = Line{}
		return nil
	}

	if src, ok := src.(string); ok {
		return scanPlanTextAnyToLineScanner{}.Scan([]byte(src), line)
	}

	return fmt.Errorf("cannot scan %T", src)
}

// Value implements the [database/sql/driver.Valuer] interface.
func (line Line) Value() (driver.Value, error) {

View on GitHub (pinned to ec1a0befd2)