feat(graphql): add JS-safe uint64 marshal helpers

Adds MarshalUint64, UnmarshalUint64, and Uint64Marshaler for gqlgen-
compatible uint64 string scalars without a gqlgen dependency.

Co-authored-by: Cursor <cursoragent@cursor.com>

CHANGELOG.md

@@ -17,6 +17,7 @@
 - `WithTxValue` for transactional functions that return a value.
 - `QueryCount`, `BuildQueryCountFn`, and `CountResult` for pagination counts.
 - `BinaryKSUID.BinExpr`, `ExprStringKSUIDs`, and flexible `Parse*Any` KSUID parsers.
+- `MarshalUint64` and `UnmarshalUint64` for JS-safe GraphQL uint64 scalars.
 - Context-aware variants for all query and mutation helpers.
 - `Delete`, `DeleteAffected`, `WithTx`, `ContainsCol`, and `CurrentDialect()`.
 - Package documentation (`doc.go`), expanded README, and subpackage docs for `dbxm` / `dbxp`.

README.md

@@ -49,6 +49,7 @@ For Postgres, use `dbx.DialectPostgres` and blank-import `dbxp` instead of `dbxm
 | Partial update | `ApplyPtr`, `ApplyComplexPtr`, `ApplyInterfacePtr`, `ApplyVal` |
 | Pointers | `Ptr`, `Val`, `NowPtr`, `TrimPtr`, `TrimPtrToNil`, `IsZero` |
 | Types | `StringKSUID`, `BinaryKSUID`, `JSONB` |
+| GraphQL | `MarshalUint64`, `UnmarshalUint64` |
 
 ## KSUID type selection
 

doc.go

@@ -33,6 +33,11 @@
 //
 // [JSONB] provides map-based JSON column scanning for Postgres JSONB and MySQL JSON.
 //
+// # GraphQL scalars
+//
+// [MarshalUint64] and [UnmarshalUint64] provide JS-safe uint64 serialization for
+// gqlgen without importing gqlgen directly.
+//
 // # Pointer and string utilities
 //
 // [Ptr], [Val], [TrimPtr], [StringToFilter], and related helpers for nullable

gql_uint64.go

@@ -0,0 +1,55 @@
+package dbx
+
+import (
+	"fmt"
+	"io"
+	"strconv"
+)
+
+// Uint64Marshaler wraps a uint64 for GraphQL JSON output as a string scalar.
+type Uint64Marshaler uint64
+
+// MarshalGQL writes the uint64 as a JSON string for gqlgen compatibility.
+func (u Uint64Marshaler) MarshalGQL(w io.Writer) {
+	fmt.Fprintf(w, "\"%d\"", uint64(u))
+}
+
+// MarshalUint64 marshals a uint64 as a JSON string to avoid JavaScript
+// precision loss for integers larger than 2^53-1.
+func MarshalUint64(i uint64) Uint64Marshaler {
+	return Uint64Marshaler(i)
+}
+
+// UnmarshalUint64 unmarshals a uint64 from a JSON string or number.
+func UnmarshalUint64(v any) (uint64, error) {
+	switch value := v.(type) {
+	case string:
+		if value == "" {
+			return 0, nil
+		}
+		n, err := strconv.ParseUint(value, 10, 64)
+		if err != nil {
+			return 0, fmt.Errorf("invalid uint64 string: %w", err)
+		}
+		return n, nil
+	case int:
+		if value < 0 {
+			return 0, fmt.Errorf("invalid negative uint64: %d", value)
+		}
+		return uint64(value), nil
+	case int64:
+		if value < 0 {
+			return 0, fmt.Errorf("invalid negative uint64: %d", value)
+		}
+		return uint64(value), nil
+	case float64:
+		if value < 0 || value != float64(uint64(value)) {
+			return 0, fmt.Errorf("invalid uint64 number: %v", value)
+		}
+		return uint64(value), nil
+	case uint64:
+		return value, nil
+	default:
+		return 0, fmt.Errorf("invalid uint64 type: %T", v)
+	}
+}

gql_uint64_test.go

@@ -0,0 +1,49 @@
+package dbx
+
+import (
+	"bytes"
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMarshalUint64(t *testing.T) {
+	var buf bytes.Buffer
+	MarshalUint64(9007199254740993).MarshalGQL(&buf)
+	assert.Equal(t, `"9007199254740993"`, buf.String())
+}
+
+func TestUnmarshalUint64_String(t *testing.T) {
+	n, err := UnmarshalUint64("42")
+	require.NoError(t, err)
+	assert.Equal(t, uint64(42), n)
+}
+
+func TestUnmarshalUint64_Number(t *testing.T) {
+	n, err := UnmarshalUint64(float64(42))
+	require.NoError(t, err)
+	assert.Equal(t, uint64(42), n)
+}
+
+func TestUnmarshalUint64_RoundTripJSON(t *testing.T) {
+	const original uint64 = 9007199254740993
+	var buf bytes.Buffer
+	MarshalUint64(original).MarshalGQL(&buf)
+
+	var wire string
+	require.NoError(t, json.Unmarshal(buf.Bytes(), &wire))
+
+	got, err := UnmarshalUint64(wire)
+	require.NoError(t, err)
+	assert.Equal(t, original, got)
+}
+
+func TestUnmarshalUint64_Invalid(t *testing.T) {
+	_, err := UnmarshalUint64(true)
+	assert.Error(t, err)
+
+	_, err = UnmarshalUint64(float64(-1))
+	assert.Error(t, err)
+}