feat(spanner): PGNumeric implements Scanner and Valuer (#13722)

olavloite · web-flow · commit 85bc9dbfb75d · 2026-01-27T07:39:05.000+01:00
Implement the Scanner and Valuer interfaces for PGNumeric so this type
is easier to use with the database/sql driver.
diff --git a/spanner/row_test.go b/spanner/row_test.go
@@ -2837,3 +2837,11 @@ func TestSelectAll(t *testing.T) {
 func stringPointer(s string) *string {
 	return &s
 }
+
+func float32Pointer(f float32) *float32 {
+	return &f
+}
+
+func float64Pointer(f float64) *float64 {
+	return &f
+}
diff --git a/spanner/value.go b/spanner/value.go
@@ -1051,6 +1051,80 @@ func (n *PGNumeric) UnmarshalJSON(payload []byte) error {
 	return nil
 }
 
+// Value implements the driver.Valuer interface.
+func (n PGNumeric) Value() (driver.Value, error) {
+	if n.IsNull() {
+		return nil, nil
+	}
+	return n.Numeric, nil
+}
+
+// Scan implements the sql.Scanner interface.
+func (n *PGNumeric) Scan(value interface{}) error {
+	if value == nil {
+		n.Numeric, n.Valid = "", false
+		return nil
+	}
+	n.Valid = true
+	switch p := value.(type) {
+	default:
+		return spannerErrorf(codes.InvalidArgument, "invalid type for PGNumeric: %v", p)
+	case *big.Rat:
+		if p == nil {
+			n.Numeric, n.Valid = "", false
+		} else {
+			n.Numeric = NumericString(p)
+		}
+	case big.Rat:
+		n.Numeric = NumericString(&p)
+	case *NullNumeric:
+		if p == nil {
+			n.Numeric, n.Valid = "", false
+		} else {
+			if p.Valid {
+				n.Numeric = p.String()
+			} else {
+				n.Numeric = ""
+			}
+			n.Valid = p.Valid
+		}
+	case NullNumeric:
+		if p.Valid {
+			n.Numeric = p.String()
+		} else {
+			n.Numeric = ""
+		}
+		n.Valid = p.Valid
+	case string:
+		n.Numeric = p
+		n.Valid = true
+	case *string:
+		if p == nil {
+			n.Numeric, n.Valid = "", false
+		} else {
+			n.Numeric = *p
+			n.Valid = true
+		}
+	case float32:
+		n.Numeric = strconv.FormatFloat(float64(p), 'f', 9, 32)
+	case *float32:
+		if p == nil {
+			n.Numeric, n.Valid = "", false
+		} else {
+			n.Numeric = strconv.FormatFloat(float64(*p), 'f', 9, 32)
+		}
+	case float64:
+		n.Numeric = strconv.FormatFloat(p, 'f', 9, 64)
+	case *float64:
+		if p == nil {
+			n.Numeric, n.Valid = "", false
+		} else {
+			n.Numeric = strconv.FormatFloat(*p, 'f', 9, 64)
+		}
+	}
+	return nil
+}
+
 // GormDataType is used by gorm to determine the default data type for fields with this type.
 func (n PGNumeric) GormDataType() string {
 	return "numeric"
diff --git a/spanner/value_test.go b/spanner/value_test.go
@@ -3562,6 +3562,45 @@ func TestScanNullNumeric(t *testing.T) {
 	}
 }
 
+func TestScanPGNumeric(t *testing.T) {
+	for _, test := range []struct {
+		name  string
+		input any
+		want  PGNumeric
+	}{
+		{name: "string", input: "3.14", want: PGNumeric{Numeric: "3.14", Valid: true}},
+		{name: "stringptr", input: stringPointer("3.14"), want: PGNumeric{Numeric: "3.14", Valid: true}},
+		{name: "nil", input: nil, want: PGNumeric{}},
+		{name: "nilstringptr", input: (*string)(nil), want: PGNumeric{}},
+		{name: "float32", input: float32(3.14), want: PGNumeric{Numeric: "3.140000105", Valid: true}},
+		{name: "float32ptr", input: float32Pointer(float32(3.14)), want: PGNumeric{Numeric: "3.140000105", Valid: true}},
+		{name: "float64", input: 3.14, want: PGNumeric{Numeric: "3.140000000", Valid: true}},
+		{name: "float64ptr", input: float64Pointer(3.14), want: PGNumeric{Numeric: "3.140000000", Valid: true}},
+		{name: "NullNumeric", input: NullNumeric{Numeric: *bigRatFromString("3.14"), Valid: true}, want: PGNumeric{Numeric: "3.140000000", Valid: true}},
+		{name: "NullNumericPtr", input: &NullNumeric{Numeric: *bigRatFromString("3.14"), Valid: true}, want: PGNumeric{Numeric: "3.140000000", Valid: true}},
+		{name: "NullNumericWithNullValue", input: NullNumeric{}, want: PGNumeric{}},
+		{name: "NullNumericPtrWithNullValue", input: &NullNumeric{}, want: PGNumeric{}},
+		{name: "bigrat", input: *bigRatFromString("6.626"), want: PGNumeric{Numeric: "6.626000000", Valid: true}},
+		{name: "bigratptr", input: bigRatFromString("9.99"), want: PGNumeric{Numeric: "9.990000000", Valid: true}},
+		{name: "nilbigratptr", input: (*big.Rat)(nil), want: PGNumeric{}},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			n := PGNumeric{Numeric: "should be overwritten", Valid: true}
+			if err := n.Scan(test.input); err != nil {
+				t.Fatal(err)
+			}
+			if g, w := n, test.want; !reflect.DeepEqual(g, w) {
+				t.Fatalf("value mismatch\n Got: %v\nWant: %v", g, w)
+			}
+		})
+	}
+}
+
+func bigRatFromString(s string) *big.Rat {
+	r, _ := (&big.Rat{}).SetString(s)
+	return r
+}
+
 func TestInterval(t *testing.T) {
 	tests := []struct {
 		name     string
