fix(encoding/gxml): XML special character encoding error (#3740)

encoding/gxml/gxml.go

@@ -49,6 +49,27 @@ func DecodeWithoutRoot(content []byte) (map[string]interface{}, error) {
 	return m, nil
 }
 
+// XMLEscapeChars forces escaping invalid characters in attribute and element values.
+// NOTE: this is brute force with NO interrogation of '&' being escaped already; if it is
+// then '&' will be re-escaped as '&'.
+//
+/*
+	The values are:
+	"   "
+	'   '
+	<   &lt;
+	>   &gt;
+	&   &amp;
+*/
+//
+// Note: if XMLEscapeCharsDecoder(true) has been called - or the default, 'false,' value
+// has been toggled to 'true' - then XMLEscapeChars(true) is ignored.  If XMLEscapeChars(true)
+// has already been called before XMLEscapeCharsDecoder(true), XMLEscapeChars(false) is called
+// to turn escape encoding on mv.Xml, etc., to prevent double escaping ampersands, '&'.
+func XMLEscapeChars(b ...bool) {
+	mxj.XMLEscapeChars(b...)
+}
+
 // Encode encodes map `m` to an XML format content as bytes.
 // The optional parameter `rootTag` is used to specify the XML root tag.
 func Encode(m map[string]interface{}, rootTag ...string) ([]byte, error) {

encoding/gxml/gxml_z_unit_test.go

@@ -206,3 +206,28 @@ func TestErrCase(t *testing.T) {
 		}
 	})
 }
+
+func Test_Issue3716(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		var (
+			xml = `<Person><Bio>I am a software developer &amp; I love coding.</Bio><Email>john.doe@example.com</Email><Name>&lt;&gt;&amp;&apos;&quot;AAA</Name></Person>`
+			m   = map[string]interface{}{
+				"Person": map[string]interface{}{
+					"Name":  "<>&'\"AAA",
+					"Email": "john.doe@example.com",
+					"Bio":   "I am a software developer & I love coding.",
+				},
+			}
+		)
+		gxml.XMLEscapeChars(true)
+		defer gxml.XMLEscapeChars(false)
+
+		xb, err := gxml.Encode(m)
+		t.AssertNil(err)
+		t.Assert(string(xb), xml)
+
+		dm, err := gxml.Decode(xb)
+		t.AssertNil(err)
+		t.Assert(dm, m)
+	})
+}