libgo: update to Go1.17rc2

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/341629

3 files changed, 72 insertions, 8 deletions

diff --git a/libgo/go/encoding/xml/typeinfo.go b/libgo/go/encoding/xml/typeinfo.go
index f30fe58590b..162724ef1a5 100644
--- a/libgo/go/encoding/xml/typeinfo.go
+++ b/libgo/go/encoding/xml/typeinfo.go
@@ -60,7 +60,7 @@ func getTypeInfo(typ reflect.Type) (*typeInfo, error) {
 		n := typ.NumField()
 		for i := 0; i < n; i++ {
 			f := typ.Field(i)
-			if (f.PkgPath != "" && !f.Anonymous) || f.Tag.Get("xml") == "-" {
+			if (!f.IsExported() && !f.Anonymous) || f.Tag.Get("xml") == "-" {
 				continue // Private field
 			}
 
diff --git a/libgo/go/encoding/xml/xml.go b/libgo/go/encoding/xml/xml.go
index 6f9594d7ba7..c14954df155 100644
--- a/libgo/go/encoding/xml/xml.go
+++ b/libgo/go/encoding/xml/xml.go
@@ -261,7 +261,7 @@ func NewTokenDecoder(t TokenReader) *Decoder {
 // call to Token. To acquire a copy of the bytes, call CopyToken
 // or the token's Copy method.
 //
-// Token expands self-closing elements such as <br/>
+// Token expands self-closing elements such as <br>
 // into separate start and end elements returned by successive calls.
 //
 // Token guarantees that the StartElement and EndElement
@@ -768,6 +768,12 @@ func (d *Decoder) rawToken() (Token, error) {
 					}
 					b0, b1 = b1, b
 				}
+
+				// Replace the comment with a space in the returned Directive
+				// body, so that markup parts that were separated by the comment
+				// (like a "<" and a "!") don't get joined when re-encoding the
+				// Directive, taking new semantic meaning.
+				d.buf.WriteByte(' ')
 			}
 		}
 		return Directive(d.buf.Bytes()), nil
@@ -1156,8 +1162,9 @@ func (d *Decoder) nsname() (name Name, ok bool) {
 	if !ok {
 		return
 	}
-	i := strings.Index(s, ":")
-	if i < 0 {
+	if strings.Count(s, ":") > 1 {
+		name.Local = s
+	} else if i := strings.Index(s, ":"); i < 1 || i > len(s)-2 {
 		name.Local = s
 	} else {
 		name.Space = s[0:i]
diff --git a/libgo/go/encoding/xml/xml_test.go b/libgo/go/encoding/xml/xml_test.go
index 5672ebb375f..19152dbdb68 100644
--- a/libgo/go/encoding/xml/xml_test.go
+++ b/libgo/go/encoding/xml/xml_test.go
@@ -802,11 +802,11 @@ var directivesWithCommentsInput = `
 
 var directivesWithCommentsTokens = []Token{
 	CharData("\n"),
-	Directive(`DOCTYPE [<!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#">]`),
+	Directive(`DOCTYPE [ <!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#">]`),
 	CharData("\n"),
-	Directive(`DOCTYPE [<!ENTITY go "Golang">]`),
+	Directive(`DOCTYPE [<!ENTITY go "Golang"> ]`),
 	CharData("\n"),
-	Directive(`DOCTYPE <!-> <!>    [<!ENTITY go "Golang">]`),
+	Directive(`DOCTYPE <!-> <!>       [<!ENTITY go "Golang"> ]`),
 	CharData("\n"),
 }
 
@@ -940,7 +940,7 @@ func (m mapper) Token() (Token, error) {
 }
 
 func TestNewTokenDecoderIdempotent(t *testing.T) {
-	d := NewDecoder(strings.NewReader(`<br/>`))
+	d := NewDecoder(strings.NewReader(`<br>`))
 	d2 := NewTokenDecoder(d)
 	if d != d2 {
 		t.Error("NewTokenDecoder did not detect underlying Decoder")
@@ -1003,3 +1003,60 @@ func TestTokenUnmarshaler(t *testing.T) {
 	d := NewTokenDecoder(tokReader{})
 	d.Decode(&Failure{})
 }
+
+func testRoundTrip(t *testing.T, input string) {
+	d := NewDecoder(strings.NewReader(input))
+	var tokens []Token
+	var buf bytes.Buffer
+	e := NewEncoder(&buf)
+	for {
+		tok, err := d.Token()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatalf("invalid input: %v", err)
+		}
+		if err := e.EncodeToken(tok); err != nil {
+			t.Fatalf("failed to re-encode input: %v", err)
+		}
+		tokens = append(tokens, CopyToken(tok))
+	}
+	if err := e.Flush(); err != nil {
+		t.Fatal(err)
+	}
+
+	d = NewDecoder(&buf)
+	for {
+		tok, err := d.Token()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatalf("failed to decode output: %v", err)
+		}
+		if len(tokens) == 0 {
+			t.Fatalf("unexpected token: %#v", tok)
+		}
+		a, b := tokens[0], tok
+		if !reflect.DeepEqual(a, b) {
+			t.Fatalf("token mismatch: %#v vs %#v", a, b)
+		}
+		tokens = tokens[1:]
+	}
+	if len(tokens) > 0 {
+		t.Fatalf("lost tokens: %#v", tokens)
+	}
+}
+
+func TestRoundTrip(t *testing.T) {
+	tests := map[string]string{
+		"leading colon":          `<::Test ::foo="bar"><:::Hello></:::Hello><Hello></Hello></::Test>`,
+		"trailing colon":         `<foo abc:="x"></foo>`,
+		"double colon":           `<x:y:foo></x:y:foo>`,
+		"comments in directives": `<!ENTITY x<!<!-- c1 [ " -->--x --> > <e></e> <!DOCTYPE xxx [ x<!-- c2 " -->--x ]>`,
+	}
+	for name, input := range tests {
+		t.Run(name, func(t *testing.T) { testRoundTrip(t, input) })
+	}
+}