encoding/xml: add docs and tests for bool whitespace

Whitespace is ignored in bool values and attrs, but there are no tests
capturing this behavior.

Change-Id: I7a7249de4886f510869e91de937e69b83c3254c8
Reviewed-on: https://go-review.googlesource.com/73890
Reviewed-by: Sam Whited <sam@samwhited.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Sam Whited <sam@samwhited.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/encoding/xml/read.go

@@ -107,7 +107,8 @@ import (
 // to the newly created value.
 //
 // Unmarshal maps an XML element or attribute value to a bool by
-// setting it to the boolean value represented by the string.
+// setting it to the boolean value represented by the string. Whitespace
+// is trimmed and ignored.
 //
 // Unmarshal maps an XML element or attribute value to an integer or
 // floating-point field by setting the field to the result of

src/encoding/xml/read_test.go

@@ -908,3 +908,60 @@ func TestUnmarshalEmptyValues(t *testing.T) {
 		t.Fatalf("populated: Unmarshal:\nhave:  %#+v\nwant: %#+v", v, want)
 	}
 }
+
+type WhitespaceValuesParent struct {
+	BFalse bool
+	BTrue  bool
+}
+
+const whitespaceValuesXML = `
+<WhitespaceValuesParent>
+    <BFalse>   false   </BFalse>
+    <BTrue>   true   </BTrue>
+</WhitespaceValuesParent>
+`
+
+// golang.org/issues/22146
+func TestUnmarshalWhitespaceValues(t *testing.T) {
+	v := WhitespaceValuesParent{}
+	if err := Unmarshal([]byte(whitespaceValuesXML), &v); err != nil {
+		t.Fatalf("whitespace values: Unmarshal failed: got %v", err)
+	}
+
+	want := WhitespaceValuesParent{
+		BFalse: false,
+		BTrue:  true,
+	}
+	if v != want {
+		t.Fatalf("whitespace values: Unmarshal:\nhave: %#+v\nwant: %#+v", v, want)
+	}
+}
+
+type WhitespaceAttrsParent struct {
+	BFalse bool `xml:",attr"`
+	BTrue  bool `xml:",attr"`
+}
+
+const whitespaceAttrsXML = `
+<WhitespaceAttrsParent
+    BFalse="  false  "
+    BTrue="  true  "
+>
+</WhitespaceAttrsParent>
+`
+
+// golang.org/issues/22146
+func TestUnmarshalWhitespaceAttrs(t *testing.T) {
+	v := WhitespaceAttrsParent{}
+	if err := Unmarshal([]byte(whitespaceAttrsXML), &v); err != nil {
+		t.Fatalf("whitespace attrs: Unmarshal failed: got %v", err)
+	}
+
+	want := WhitespaceAttrsParent{
+		BFalse: false,
+		BTrue:  true,
+	}
+	if v != want {
+		t.Fatalf("whitespace attrs: Unmarshal:\nhave: %#+v\nwant: %#+v", v, want)
+	}
+}