encoding/xml: improve package based on the suggestions from metalinter

Existing code in encoding/xml packages contains code which breaks
various linter rules (comments, constant and variable naming, variable
shadowing, etc).

Fixes #21578

Change-Id: Id4bd9a9be6d5728ce88fb6efe33030ef943c078c
Reviewed-on: https://go-review.googlesource.com/58210
Reviewed-by: Sam Whited <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Run-TryBot: Sam Whited <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>

Author: pazderak

src/encoding/xml/atom_test.go

@@ -12,20 +12,20 @@ var atomValue = &Feed{
 	Link:    []Link{{Href: "http://example.org/"}},
 	Updated: ParseTime("2003-12-13T18:30:02Z"),
 	Author:  Person{Name: "John Doe"},
-	Id:      "urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6",
+	ID:      "urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6",
 
 	Entry: []Entry{
 		{
 			Title:   "Atom-Powered Robots Run Amok",
 			Link:    []Link{{Href: "http://example.org/2003/12/13/atom03"}},
-			Id:      "urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a",
+			ID:      "urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a",
 			Updated: ParseTime("2003-12-13T18:30:02Z"),
 			Summary: NewText("Some text."),
 		},
 	},
 }
 
-var atomXml = `` +
+var atomXML = `` +
 	`<feed xmlns="http://www.w3.org/2005/Atom" updated="2003-12-13T18:30:02Z">` +
 	`<title>Example Feed</title>` +
 	`<id>urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6</id>` +

src/encoding/xml/marshal.go

@@ -16,10 +16,11 @@ import (
 )
 
 const (
-	// A generic XML header suitable for use with the output of Marshal.
+	// Header is a generic XML header suitable for use with the output of Marshal.
 	// This is not automatically added to any output of this package,
 	// it is provided as a convenience.
-	Header = `<?xml version="1.0" encoding="UTF-8"?>` + "\n"
+	Header             = `<?xml version="1.0" encoding="UTF-8"?>` + "\n"
+	xmlNamespacePrefix = "xml"
 )
 
 // Marshal returns the XML encoding of v.
@@ -320,7 +321,7 @@ func (p *printer) createAttrPrefix(url string) string {
 	// (The "http://www.w3.org/2000/xmlns/" name space is also predefined as "xmlns",
 	// but users should not be trying to use that one directly - that's our job.)
 	if url == xmlURL {
-		return "xml"
+		return xmlNamespacePrefix
 	}
 
 	// Need to define a new name space.
@@ -1011,7 +1012,7 @@ func (s *parentStack) push(parents []string) error {
 	return nil
 }
 
-// A MarshalXMLError is returned when Marshal encounters a type
+// UnsupportedTypeError is returned when Marshal encounters a type
 // that cannot be converted into XML.
 type UnsupportedTypeError struct {
 	Type reflect.Type

src/encoding/xml/marshal_test.go

@@ -646,7 +646,7 @@ var marshalTests = []struct {
 	{Value: &Universe{Visible: 9.3e13}, ExpectXML: `<universe>9.3e+13</universe>`},
 	{Value: &Particle{HasMass: true}, ExpectXML: `<particle>true</particle>`},
 	{Value: &Departure{When: ParseTime("2013-01-09T00:15:00-09:00")}, ExpectXML: `<departure>2013-01-09T00:15:00-09:00</departure>`},
-	{Value: atomValue, ExpectXML: atomXml},
+	{Value: atomValue, ExpectXML: atomXML},
 	{
 		Value: &Ship{
 			Name:  "Heart of Gold",
@@ -1910,7 +1910,7 @@ func BenchmarkMarshal(b *testing.B) {
 
 func BenchmarkUnmarshal(b *testing.B) {
 	b.ReportAllocs()
-	xml := []byte(atomXml)
+	xml := []byte(atomXML)
 	b.RunParallel(func(pb *testing.PB) {
 		for pb.Next() {
 			Unmarshal(xml, &Feed{})

src/encoding/xml/read.go

@@ -192,19 +192,19 @@ func receiverType(val interface{}) string {
 
 // unmarshalInterface unmarshals a single XML element into val.
 // start is the opening tag of the element.
-func (p *Decoder) unmarshalInterface(val Unmarshaler, start *StartElement) error {
+func (d *Decoder) unmarshalInterface(val Unmarshaler, start *StartElement) error {
 	// Record that decoder must stop at end tag corresponding to start.
-	p.pushEOF()
+	d.pushEOF()
 
-	p.unmarshalDepth++
-	err := val.UnmarshalXML(p, *start)
-	p.unmarshalDepth--
+	d.unmarshalDepth++
+	err := val.UnmarshalXML(d, *start)
+	d.unmarshalDepth--
 	if err != nil {
-		p.popEOF()
+		d.popEOF()
 		return err
 	}
 
-	if !p.popEOF() {
+	if !d.popEOF() {
 		return fmt.Errorf("xml: %s.UnmarshalXML did not consume entire <%s> element", receiverType(val), start.Name.Local)
 	}
 
@@ -214,11 +214,11 @@ func (p *Decoder) unmarshalInterface(val Unmarshaler, start *StartElement) error
 // unmarshalTextInterface unmarshals a single XML element into val.
 // The chardata contained in the element (but not its children)
 // is passed to the text unmarshaler.
-func (p *Decoder) unmarshalTextInterface(val encoding.TextUnmarshaler) error {
+func (d *Decoder) unmarshalTextInterface(val encoding.TextUnmarshaler) error {
 	var buf []byte
 	depth := 1
 	for depth > 0 {
-		t, err := p.Token()
+		t, err := d.Token()
 		if err != nil {
 			return err
 		}
@@ -237,7 +237,7 @@ func (p *Decoder) unmarshalTextInterface(val encoding.TextUnmarshaler) error {
 }
 
 // unmarshalAttr unmarshals a single XML attribute into val.
-func (p *Decoder) unmarshalAttr(val reflect.Value, attr Attr) error {
+func (d *Decoder) unmarshalAttr(val reflect.Value, attr Attr) error {
 	if val.Kind() == reflect.Ptr {
 		if val.IsNil() {
 			val.Set(reflect.New(val.Type().Elem()))
@@ -276,7 +276,7 @@ func (p *Decoder) unmarshalAttr(val reflect.Value, attr Attr) error {
 		val.Set(reflect.Append(val, reflect.Zero(val.Type().Elem())))
 
 		// Recur to read element into slice.
-		if err := p.unmarshalAttr(val.Index(n), attr); err != nil {
+		if err := d.unmarshalAttr(val.Index(n), attr); err != nil {
 			val.SetLen(n)
 			return err
 		}
@@ -299,11 +299,11 @@ var (
 )
 
 // Unmarshal a single XML element into val.
-func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
+func (d *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 	// Find start element if we need it.
 	if start == nil {
 		for {
-			tok, err := p.Token()
+			tok, err := d.Token()
 			if err != nil {
 				return err
 			}
@@ -333,24 +333,24 @@ func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 	if val.CanInterface() && val.Type().Implements(unmarshalerType) {
 		// This is an unmarshaler with a non-pointer receiver,
 		// so it's likely to be incorrect, but we do what we're told.
-		return p.unmarshalInterface(val.Interface().(Unmarshaler), start)
+		return d.unmarshalInterface(val.Interface().(Unmarshaler), start)
 	}
 
 	if val.CanAddr() {
 		pv := val.Addr()
 		if pv.CanInterface() && pv.Type().Implements(unmarshalerType) {
-			return p.unmarshalInterface(pv.Interface().(Unmarshaler), start)
+			return d.unmarshalInterface(pv.Interface().(Unmarshaler), start)
 		}
 	}
 
 	if val.CanInterface() && val.Type().Implements(textUnmarshalerType) {
-		return p.unmarshalTextInterface(val.Interface().(encoding.TextUnmarshaler))
+		return d.unmarshalTextInterface(val.Interface().(encoding.TextUnmarshaler))
 	}
 
 	if val.CanAddr() {
 		pv := val.Addr()
 		if pv.CanInterface() && pv.Type().Implements(textUnmarshalerType) {
-			return p.unmarshalTextInterface(pv.Interface().(encoding.TextUnmarshaler))
+			return d.unmarshalTextInterface(pv.Interface().(encoding.TextUnmarshaler))
 		}
 	}
 
@@ -376,7 +376,7 @@ func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 		// TODO: For now, simply ignore the field. In the near
 		//       future we may choose to unmarshal the start
 		//       element on it, if not nil.
-		return p.Skip()
+		return d.Skip()
 
 	case reflect.Slice:
 		typ := v.Type()
@@ -392,7 +392,7 @@ func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 		v.Set(reflect.Append(val, reflect.Zero(v.Type().Elem())))
 
 		// Recur to read element into slice.
-		if err := p.unmarshal(v.Index(n), start); err != nil {
+		if err := d.unmarshal(v.Index(n), start); err != nil {
 			v.SetLen(n)
 			return err
 		}
@@ -445,7 +445,7 @@ func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 				case fAttr:
 					strv := finfo.value(sv)
 					if a.Name.Local == finfo.name && (finfo.xmlns == "" || finfo.xmlns == a.Name.Space) {
-						if err := p.unmarshalAttr(strv, a); err != nil {
+						if err := d.unmarshalAttr(strv, a); err != nil {
 							return err
 						}
 						handled = true
@@ -460,7 +460,7 @@ func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 			if !handled && any >= 0 {
 				finfo := &tinfo.fields[any]
 				strv := finfo.value(sv)
-				if err := p.unmarshalAttr(strv, a); err != nil {
+				if err := d.unmarshalAttr(strv, a); err != nil {
 					return err
 				}
 			}
@@ -488,11 +488,11 @@ func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 			case fInnerXml:
 				if !saveXML.IsValid() {
 					saveXML = finfo.value(sv)
-					if p.saved == nil {
+					if d.saved == nil {
 						saveXMLIndex = 0
-						p.saved = new(bytes.Buffer)
+						d.saved = new(bytes.Buffer)
 					} else {
-						saveXMLIndex = p.savedOffset()
+						saveXMLIndex = d.savedOffset()
 					}
 				}
 			}
@@ -505,38 +505,38 @@ Loop:
 	for {
 		var savedOffset int
 		if saveXML.IsValid() {
-			savedOffset = p.savedOffset()
+			savedOffset = d.savedOffset()
 		}
-		tok, err := p.Token()
+		tok, err := d.Token()
 		if err != nil {
 			return err
 		}
 		switch t := tok.(type) {
 		case StartElement:
 			consumed := false
 			if sv.IsValid() {
-				consumed, err = p.unmarshalPath(tinfo, sv, nil, &t)
+				consumed, err = d.unmarshalPath(tinfo, sv, nil, &t)
 				if err != nil {
 					return err
 				}
 				if !consumed && saveAny.IsValid() {
 					consumed = true
-					if err := p.unmarshal(saveAny, &t); err != nil {
+					if err := d.unmarshal(saveAny, &t); err != nil {
 						return err
 					}
 				}
 			}
 			if !consumed {
-				if err := p.Skip(); err != nil {
+				if err := d.Skip(); err != nil {
 					return err
 				}
 			}
 
 		case EndElement:
 			if saveXML.IsValid() {
-				saveXMLData = p.saved.Bytes()[saveXMLIndex:savedOffset]
+				saveXMLData = d.saved.Bytes()[saveXMLIndex:savedOffset]
 				if saveXMLIndex == 0 {
-					p.saved = nil
+					d.saved = nil
 				}
 			}
 			break Loop
@@ -666,7 +666,7 @@ func copyValue(dst reflect.Value, src []byte) (err error) {
 // The consumed result tells whether XML elements have been consumed
 // from the Decoder until start's matching end element, or if it's
 // still untouched because start is uninteresting for sv's fields.
-func (p *Decoder) unmarshalPath(tinfo *typeInfo, sv reflect.Value, parents []string, start *StartElement) (consumed bool, err error) {
+func (d *Decoder) unmarshalPath(tinfo *typeInfo, sv reflect.Value, parents []string, start *StartElement) (consumed bool, err error) {
 	recurse := false
 Loop:
 	for i := range tinfo.fields {
@@ -681,7 +681,7 @@ Loop:
 		}
 		if len(finfo.parents) == len(parents) && finfo.name == start.Name.Local {
 			// It's a perfect match, unmarshal the field.
-			return true, p.unmarshal(finfo.value(sv), start)
+			return true, d.unmarshal(finfo.value(sv), start)
 		}
 		if len(finfo.parents) > len(parents) && finfo.parents[len(parents)] == start.Name.Local {
 			// It's a prefix for the field. Break and recurse
@@ -704,18 +704,18 @@ Loop:
 	// prefix. Recurse and attempt to match these.
 	for {
 		var tok Token
-		tok, err = p.Token()
+		tok, err = d.Token()
 		if err != nil {
 			return true, err
 		}
 		switch t := tok.(type) {
 		case StartElement:
-			consumed2, err := p.unmarshalPath(tinfo, sv, parents, &t)
+			consumed2, err := d.unmarshalPath(tinfo, sv, parents, &t)
 			if err != nil {
 				return true, err
 			}
 			if !consumed2 {
-				if err := p.Skip(); err != nil {
+				if err := d.Skip(); err != nil {
 					return true, err
 				}
 			}

src/encoding/xml/read_test.go

@@ -83,7 +83,7 @@ not being used from outside intra_region_diff.py.
 type Feed struct {
 	XMLName Name      `xml:"http://www.w3.org/2005/Atom feed"`
 	Title   string    `xml:"title"`
-	Id      string    `xml:"id"`
+	ID      string    `xml:"id"`
 	Link    []Link    `xml:"link"`
 	Updated time.Time `xml:"updated,attr"`
 	Author  Person    `xml:"author"`
@@ -92,7 +92,7 @@ type Feed struct {
 
 type Entry struct {
 	Title   string    `xml:"title"`
-	Id      string    `xml:"id"`
+	ID      string    `xml:"id"`
 	Link    []Link    `xml:"link"`
 	Updated time.Time `xml:"updated"`
 	Author  Person    `xml:"author"`
@@ -123,7 +123,7 @@ var atomFeed = Feed{
 		{Rel: "alternate", Href: "http://codereview.appspot.com/"},
 		{Rel: "self", Href: "http://codereview.appspot.com/rss/mine/rsc"},
 	},
-	Id:      "http://codereview.appspot.com/",
+	ID:      "http://codereview.appspot.com/",
 	Updated: ParseTime("2009-10-04T01:35:58+00:00"),
 	Author: Person{
 		Name:     "rietveld<>",
@@ -140,7 +140,7 @@ var atomFeed = Feed{
 				Name:     "email-address-removed",
 				InnerXML: "<name>email-address-removed</name>",
 			},
-			Id: "urn:md5:134d9179c41f806be79b3a5f7877d19a",
+			ID: "urn:md5:134d9179c41f806be79b3a5f7877d19a",
 			Summary: Text{
 				Type: "html",
 				Body: `
@@ -187,7 +187,7 @@ the top of feeds.py marked NOTE(rsc).
 				Name:     "email-address-removed",
 				InnerXML: "<name>email-address-removed</name>",
 			},
-			Id: "urn:md5:0a2a4f19bb815101f0ba2904aed7c35a",
+			ID: "urn:md5:0a2a4f19bb815101f0ba2904aed7c35a",
 			Summary: Text{
 				Type: "html",
 				Body: `