os.Error API: don't export os.ErrorString, use os.NewError consistently

This is a core API change.

1) gofix misc src
2) Manual adjustments to the following files under src/pkg:
   gob/decode.go
   rpc/client.go
   os/error.go
   io/io.go
   bufio/bufio.go
   http/request.go
   websocket/client.go
as well as:
   src/cmd/gofix/testdata/*.go.in (reverted)
   test/fixedbugs/bug243.go
3) Implemented gofix patch (oserrorstring.go) and test case (oserrorstring_test.go)

Compiles and runs all tests.

R=r, rsc, gri
CC=golang-dev
https://golang.org/cl/4607052

conn.go

@@ -790,10 +790,10 @@ func (c *Conn) VerifyHostname(host string) os.Error {
 	c.handshakeMutex.Lock()
 	defer c.handshakeMutex.Unlock()
 	if !c.isClient {
-		return os.ErrorString("VerifyHostname called on TLS server connection")
+		return os.NewError("VerifyHostname called on TLS server connection")
 	}
 	if !c.handshakeComplete {
-		return os.ErrorString("TLS handshake has not yet been performed")
+		return os.NewError("TLS handshake has not yet been performed")
 	}
 	return c.peerCertificates[0].VerifyHostname(host)
 }

handshake_client.go

@@ -40,7 +40,7 @@ func (c *Conn) clientHandshake() os.Error {
 	_, err := io.ReadFull(c.config.rand(), hello.random[4:])
 	if err != nil {
 		c.sendAlert(alertInternalError)
-		return os.ErrorString("short read from Rand")
+		return os.NewError("short read from Rand")
 	}
 
 	finishedHash.Write(hello.marshal())
@@ -69,7 +69,7 @@ func (c *Conn) clientHandshake() os.Error {
 
 	if !hello.nextProtoNeg && serverHello.nextProtoNeg {
 		c.sendAlert(alertHandshakeFailure)
-		return os.ErrorString("server advertised unrequested NPN")
+		return os.NewError("server advertised unrequested NPN")
 	}
 
 	suite, suiteId := mutualCipherSuite(c.config.cipherSuites(), serverHello.cipherSuite)
@@ -92,7 +92,7 @@ func (c *Conn) clientHandshake() os.Error {
 		cert, err := x509.ParseCertificate(asn1Data)
 		if err != nil {
 			c.sendAlert(alertBadCertificate)
-			return os.ErrorString("failed to parse certificate from server: " + err.String())
+			return os.NewError("failed to parse certificate from server: " + err.String())
 		}
 		certs[i] = cert
 	}

handshake_server.go

@@ -173,7 +173,7 @@ FindCipherSuite:
 			cert, err := x509.ParseCertificate(asn1Data)
 			if err != nil {
 				c.sendAlert(alertBadCertificate)
-				return os.ErrorString("could not parse client's certificate: " + err.String())
+				return os.NewError("could not parse client's certificate: " + err.String())
 			}
 			certs[i] = cert
 		}
@@ -182,7 +182,7 @@ FindCipherSuite:
 		for i := 1; i < len(certs); i++ {
 			if err := certs[i-1].CheckSignatureFrom(certs[i]); err != nil {
 				c.sendAlert(alertBadCertificate)
-				return os.ErrorString("could not validate certificate signature: " + err.String())
+				return os.NewError("could not validate certificate signature: " + err.String())
 			}
 		}
 
@@ -229,7 +229,7 @@ FindCipherSuite:
 		err = rsa.VerifyPKCS1v15(pub, crypto.MD5SHA1, digest, certVerify.signature)
 		if err != nil {
 			c.sendAlert(alertBadCertificate)
-			return os.ErrorString("could not validate signature of connection nonces: " + err.String())
+			return os.NewError("could not validate signature of connection nonces: " + err.String())
 		}
 
 		finishedHash.Write(certVerify.marshal())

key_agreement.go

@@ -32,11 +32,11 @@ func (ka rsaKeyAgreement) processClientKeyExchange(config *Config, ckx *clientKe
 	}
 
 	if len(ckx.ciphertext) < 2 {
-		return nil, os.ErrorString("bad ClientKeyExchange")
+		return nil, os.NewError("bad ClientKeyExchange")
 	}
 	ciphertextLen := int(ckx.ciphertext[0])<<8 | int(ckx.ciphertext[1])
 	if ciphertextLen != len(ckx.ciphertext)-2 {
-		return nil, os.ErrorString("bad ClientKeyExchange")
+		return nil, os.NewError("bad ClientKeyExchange")
 	}
 	ciphertext := ckx.ciphertext[2:]
 
@@ -54,7 +54,7 @@ func (ka rsaKeyAgreement) processClientKeyExchange(config *Config, ckx *clientKe
 }
 
 func (ka rsaKeyAgreement) processServerKeyExchange(config *Config, clientHello *clientHelloMsg, serverHello *serverHelloMsg, cert *x509.Certificate, skx *serverKeyExchangeMsg) os.Error {
-	return os.ErrorString("unexpected ServerKeyExchange")
+	return os.NewError("unexpected ServerKeyExchange")
 }
 
 func (ka rsaKeyAgreement) generateClientKeyExchange(config *Config, clientHello *clientHelloMsg, cert *x509.Certificate) ([]byte, *clientKeyExchangeMsg, os.Error) {
@@ -146,7 +146,7 @@ Curve:
 	md5sha1 := md5SHA1Hash(clientHello.random, hello.random, serverECDHParams)
 	sig, err := rsa.SignPKCS1v15(config.rand(), config.Certificates[0].PrivateKey, crypto.MD5SHA1, md5sha1)
 	if err != nil {
-		return nil, os.ErrorString("failed to sign ECDHE parameters: " + err.String())
+		return nil, os.NewError("failed to sign ECDHE parameters: " + err.String())
 	}
 
 	skx := new(serverKeyExchangeMsg)
@@ -162,11 +162,11 @@ Curve:
 
 func (ka *ecdheRSAKeyAgreement) processClientKeyExchange(config *Config, ckx *clientKeyExchangeMsg) ([]byte, os.Error) {
 	if len(ckx.ciphertext) == 0 || int(ckx.ciphertext[0]) != len(ckx.ciphertext)-1 {
-		return nil, os.ErrorString("bad ClientKeyExchange")
+		return nil, os.NewError("bad ClientKeyExchange")
 	}
 	x, y := ka.curve.Unmarshal(ckx.ciphertext[1:])
 	if x == nil {
-		return nil, os.ErrorString("bad ClientKeyExchange")
+		return nil, os.NewError("bad ClientKeyExchange")
 	}
 	x, _ = ka.curve.ScalarMult(x, y, ka.privateKey)
 	preMasterSecret := make([]byte, (ka.curve.BitSize+7)>>3)
@@ -176,14 +176,14 @@ func (ka *ecdheRSAKeyAgreement) processClientKeyExchange(config *Config, ckx *cl
 	return preMasterSecret, nil
 }
 
-var errServerKeyExchange = os.ErrorString("invalid ServerKeyExchange")
+var errServerKeyExchange = os.NewError("invalid ServerKeyExchange")
 
 func (ka *ecdheRSAKeyAgreement) processServerKeyExchange(config *Config, clientHello *clientHelloMsg, serverHello *serverHelloMsg, cert *x509.Certificate, skx *serverKeyExchangeMsg) os.Error {
 	if len(skx.key) < 4 {
 		return errServerKeyExchange
 	}
 	if skx.key[0] != 3 { // named curve
-		return os.ErrorString("server selected unsupported curve")
+		return os.NewError("server selected unsupported curve")
 	}
 	curveid := uint16(skx.key[1])<<8 | uint16(skx.key[2])
 
@@ -195,7 +195,7 @@ func (ka *ecdheRSAKeyAgreement) processServerKeyExchange(config *Config, clientH
 	case curveP521:
 		ka.curve = elliptic.P521()
 	default:
-		return os.ErrorString("server selected unsupported curve")
+		return os.NewError("server selected unsupported curve")
 	}
 
 	publicLen := int(skx.key[3])
@@ -224,7 +224,7 @@ func (ka *ecdheRSAKeyAgreement) processServerKeyExchange(config *Config, clientH
 
 func (ka *ecdheRSAKeyAgreement) generateClientKeyExchange(config *Config, clientHello *clientHelloMsg, cert *x509.Certificate) ([]byte, *clientKeyExchangeMsg, os.Error) {
 	if ka.curve == nil {
-		return nil, nil, os.ErrorString("missing ServerKeyExchange message")
+		return nil, nil, os.NewError("missing ServerKeyExchange message")
 	}
 	priv, mx, my, err := ka.curve.GenerateKey(config.rand())
 	if err != nil {

tls.go

@@ -147,19 +147,19 @@ func X509KeyPair(certPEMBlock, keyPEMBlock []byte) (cert Certificate, err os.Err
 	}
 
 	if len(cert.Certificate) == 0 {
-		err = os.ErrorString("crypto/tls: failed to parse certificate PEM data")
+		err = os.NewError("crypto/tls: failed to parse certificate PEM data")
 		return
 	}
 
 	keyDERBlock, _ := pem.Decode(keyPEMBlock)
 	if keyDERBlock == nil {
-		err = os.ErrorString("crypto/tls: failed to parse key PEM data")
+		err = os.NewError("crypto/tls: failed to parse key PEM data")
 		return
 	}
 
 	key, err := x509.ParsePKCS1PrivateKey(keyDERBlock.Bytes)
 	if err != nil {
-		err = os.ErrorString("crypto/tls: failed to parse key: " + err.String())
+		err = os.NewError("crypto/tls: failed to parse key: " + err.String())
 		return
 	}
 
@@ -173,7 +173,7 @@ func X509KeyPair(certPEMBlock, keyPEMBlock []byte) (cert Certificate, err os.Err
 	}
 
 	if x509Cert.PublicKeyAlgorithm != x509.RSA || x509Cert.PublicKey.(*rsa.PublicKey).N.Cmp(key.PublicKey.N) != 0 {
-		err = os.ErrorString("crypto/tls: private key does not match public key")
+		err = os.NewError("crypto/tls: private key does not match public key")
 		return
 	}