Guard using options to avoid a crash bug

Author: evanphx

v5/patch.go

@@ -142,13 +142,21 @@ func (n *partialDoc) TrustMarshalJSON(buf *bytes.Buffer) error {
 if err := buf.WriteByte('{'); err != nil {
 return err
 }
+escaped := true
+
+// n.opts should always be set, but in case we missed a case,
+// guard.
+if n.opts != nil {
+escaped = n.opts.EscapeHTML
+}
+
 for i, k := range n.keys {
 if i > 0 {
 if err := buf.WriteByte(','); err != nil {
 return err
 }
 }
-key, err := json.MarshalEscaped(k, n.opts.EscapeHTML)
+key, err := json.MarshalEscaped(k, escaped)
 if err != nil {
 return err
 }
@@ -158,7 +166,7 @@ func (n *partialDoc) TrustMarshalJSON(buf *bytes.Buffer) error {
 if err := buf.WriteByte(':'); err != nil {
 return err
 }
-value, err := json.MarshalEscaped(n.obj[k], n.opts.EscapeHTML)
+value, err := json.MarshalEscaped(n.obj[k], escaped)
 if err != nil {
 return err
 }