feat: add the required tag option and UnmarshalerContext

Assisted-by: GLM 5.3 Flash

interpres.go

@@ -241,7 +241,9 @@ func UnmarshalContext(ctx context.Context, data []byte, v any) error {
 	if err != nil {
 		return err
 	}
-	return newDecoder().decode(tree, v)
+	dec := newDecoder()
+	dec.ctx = ctx
+	return dec.decode(tree, v)
 }
 
 // A Decoder decodes a TOML document into a Go value with configurable
@@ -315,6 +317,7 @@ func (d *Decoder) DecodeContext(ctx context.Context, data []byte, v any) error {
 	}
 	dec := newDecoder()
 	dec.disallowUnknown = d.disallowUnknown
+	dec.ctx = ctx
 	return dec.decode(tree, v)
 }
 
@@ -336,7 +339,8 @@ type Marshaler interface {
 // argument is whatever the parser produced for that key: one of string,
 // bool, int64, float64, OffsetDateTime, LocalDateTime, LocalDate, LocalTime,
 // []any, or map[string]any. A tree built by hand may carry a plain time.Time
-// where the parser would put an OffsetDateTime.
+// where the parser would put an OffsetDateTime, and a Decoder configured with
+// UseNumber a Number.
 //
 // UnmarshalTOML may parse, inspect, or transform the value however it likes,
 // then store the result by mutating its receiver through the standard
@@ -355,6 +359,15 @@ type Unmarshaler interface {
 	UnmarshalTOML(data any) error
 }
 
+// UnmarshalerContext is Unmarshaler with the decode's context handed in. A
+// type that implements both interfaces gets UnmarshalTOMLContext, so a long
+// custom decode can abort on cancellation instead of running to completion.
+// The context a non-cancellable entry point carries is context.Background,
+// never nil.
+type UnmarshalerContext interface {
+	UnmarshalTOMLContext(ctx context.Context, data any) error
+}
+
 // Marshal returns the TOML encoding of v. The output is valid TOML 1.1.
 //
 // Marshal traverses v using reflection and applies the following rules: