all: deprecate NoContext

There is no good reason why we suggest NoContext rather than
context.Background(). When the oauth2 library first came around, the
community was not familiar with the x/net/context package. For
documentation reasons, we decided to add NoContext to the oauth2
package. It was not a good idea even back then. And given that context
package is fairly popular, there is no good reason why we are
depending on this.

Updating all the references of NoContext with context.Background
and documenting it as deprecated.

Change-Id: I18e390f1351023a29b567777a3f963dd550cf657
Reviewed-on: https://go-review.googlesource.com/27690
Reviewed-by: Chris Broadfoot <cbro@golang.org>

clientcredentials/clientcredentials_test.go

@@ -5,12 +5,11 @@
 package clientcredentials
 
 import (
+	"context"
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
 	"testing"
-
-	"golang.org/x/oauth2"
 )
 
 func newConf(url string) *Config {
@@ -57,7 +56,7 @@ func TestTokenRequest(t *testing.T) {
 	}))
 	defer ts.Close()
 	conf := newConf(ts.URL)
-	tok, err := conf.Token(oauth2.NoContext)
+	tok, err := conf.Token(context.Background())
 	if err != nil {
 		t.Error(err)
 	}
@@ -91,6 +90,6 @@ func TestTokenRefreshRequest(t *testing.T) {
 	}))
 	defer ts.Close()
 	conf := newConf(ts.URL)
-	c := conf.Client(oauth2.NoContext)
+	c := conf.Client(context.Background())
 	c.Get(ts.URL + "/somethingelse")
 }

example_test.go

@@ -5,6 +5,7 @@
 package oauth2_test
 
 import (
+	"context"
 	"fmt"
 	"log"
 
@@ -12,6 +13,7 @@ import (
 )
 
 func ExampleConfig() {
+	ctx := context.Background()
 	conf := &oauth2.Config{
 		ClientID:     "YOUR_CLIENT_ID",
 		ClientSecret: "YOUR_CLIENT_SECRET",
@@ -35,11 +37,11 @@ func ExampleConfig() {
 	if _, err := fmt.Scan(&code); err != nil {
 		log.Fatal(err)
 	}
-	tok, err := conf.Exchange(oauth2.NoContext, code)
+	tok, err := conf.Exchange(ctx, code)
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	client := conf.Client(oauth2.NoContext, tok)
+	client := conf.Client(ctx, tok)
 	client.Get("...")
 }

jwt/example_test.go

@@ -5,11 +5,13 @@
 package jwt_test
 
 import (
-	"golang.org/x/oauth2"
+	"context"
+
 	"golang.org/x/oauth2/jwt"
 )
 
 func ExampleJWTConfig() {
+	ctx := context.Background()
 	conf := &jwt.Config{
 		Email: "xxx@developer.com",
 		// The contents of your RSA private key or your PEM file
@@ -26,6 +28,6 @@ func ExampleJWTConfig() {
 	}
 	// Initiate an http.Client, the following GET request will be
 	// authorized and authenticated on the behalf of user@example.com.
-	client := conf.Client(oauth2.NoContext)
+	client := conf.Client(ctx)
 	client.Get("...")
 }

jwt/jwt_test.go

@@ -5,11 +5,10 @@
 package jwt
 
 import (
+	"context"
 	"net/http"
 	"net/http/httptest"
 	"testing"
-
-	"golang.org/x/oauth2"
 )
 
 var dummyPrivateKey = []byte(`-----BEGIN RSA PRIVATE KEY-----
@@ -57,7 +56,7 @@ func TestJWTFetch_JSONResponse(t *testing.T) {
 		PrivateKey: dummyPrivateKey,
 		TokenURL:   ts.URL,
 	}
-	tok, err := conf.TokenSource(oauth2.NoContext).Token()
+	tok, err := conf.TokenSource(context.Background()).Token()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -91,7 +90,7 @@ func TestJWTFetch_BadResponse(t *testing.T) {
 		PrivateKey: dummyPrivateKey,
 		TokenURL:   ts.URL,
 	}
-	tok, err := conf.TokenSource(oauth2.NoContext).Token()
+	tok, err := conf.TokenSource(context.Background()).Token()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -124,7 +123,7 @@ func TestJWTFetch_BadResponseType(t *testing.T) {
 		PrivateKey: dummyPrivateKey,
 		TokenURL:   ts.URL,
 	}
-	tok, err := conf.TokenSource(oauth2.NoContext).Token()
+	tok, err := conf.TokenSource(context.Background()).Token()
 	if err == nil {
 		t.Error("got a token; expected error")
 		if tok.AccessToken != "" {

oauth2.go

@@ -21,6 +21,8 @@ import (
 
 // NoContext is the default context you should supply if not using
 // your own context.Context (see https://golang.org/x/net/context).
+//
+// Deprecated: Use context.Background() or context.TODO() instead.
 var NoContext = context.TODO()
 
 // RegisterBrokenAuthHeaderProvider registers an OAuth2 server

oauth2_test.go

@@ -97,7 +97,7 @@ func TestExchangeRequest(t *testing.T) {
 	}))
 	defer ts.Close()
 	conf := newConf(ts.URL)
-	tok, err := conf.Exchange(NoContext, "exchange-code")
+	tok, err := conf.Exchange(context.Background(), "exchange-code")
 	if err != nil {
 		t.Error(err)
 	}
@@ -141,7 +141,7 @@ func TestExchangeRequest_JSONResponse(t *testing.T) {
 	}))
 	defer ts.Close()
 	conf := newConf(ts.URL)
-	tok, err := conf.Exchange(NoContext, "exchange-code")
+	tok, err := conf.Exchange(context.Background(), "exchange-code")
 	if err != nil {
 		t.Error(err)
 	}
@@ -236,7 +236,7 @@ func testExchangeRequest_JSONResponse_expiry(t *testing.T, exp string, expect er
 	defer ts.Close()
 	conf := newConf(ts.URL)
 	t1 := time.Now().Add(day)
-	tok, err := conf.Exchange(NoContext, "exchange-code")
+	tok, err := conf.Exchange(context.Background(), "exchange-code")
 	t2 := time.Now().Add(day)
 	// Do a fmt.Sprint comparison so either side can be
 	// nil. fmt.Sprint just stringifies them to "<nil>", and no
@@ -269,7 +269,7 @@ func TestExchangeRequest_BadResponse(t *testing.T) {
 	}))
 	defer ts.Close()
 	conf := newConf(ts.URL)
-	tok, err := conf.Exchange(NoContext, "code")
+	tok, err := conf.Exchange(context.Background(), "code")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -285,7 +285,7 @@ func TestExchangeRequest_BadResponseType(t *testing.T) {
 	}))
 	defer ts.Close()
 	conf := newConf(ts.URL)
-	_, err := conf.Exchange(NoContext, "exchange-code")
+	_, err := conf.Exchange(context.Background(), "exchange-code")
 	if err == nil {
 		t.Error("expected error from invalid access_token type")
 	}
@@ -344,7 +344,7 @@ func TestPasswordCredentialsTokenRequest(t *testing.T) {
 	}))
 	defer ts.Close()
 	conf := newConf(ts.URL)
-	tok, err := conf.PasswordCredentialsToken(NoContext, "user1", "password1")
+	tok, err := conf.PasswordCredentialsToken(context.Background(), "user1", "password1")
 	if err != nil {
 		t.Error(err)
 	}
@@ -380,7 +380,7 @@ func TestTokenRefreshRequest(t *testing.T) {
 	}))
 	defer ts.Close()
 	conf := newConf(ts.URL)
-	c := conf.Client(NoContext, &Token{RefreshToken: "REFRESH_TOKEN"})
+	c := conf.Client(context.Background(), &Token{RefreshToken: "REFRESH_TOKEN"})
 	c.Get(ts.URL + "/somethingelse")
 }
 
@@ -403,7 +403,7 @@ func TestFetchWithNoRefreshToken(t *testing.T) {
 	}))
 	defer ts.Close()
 	conf := newConf(ts.URL)
-	c := conf.Client(NoContext, nil)
+	c := conf.Client(context.Background(), nil)
 	_, err := c.Get(ts.URL + "/somethingelse")
 	if err == nil {
 		t.Errorf("Fetch should return an error if no refresh token is set")
@@ -420,7 +420,7 @@ func TestRefreshToken_RefreshTokenReplacement(t *testing.T) {
 	conf := newConf(ts.URL)
 	tkr := tokenRefresher{
 		conf:         conf,
-		ctx:          NoContext,
+		ctx:          context.Background(),
 		refreshToken: "OLD REFRESH TOKEN",
 	}
 	tk, err := tkr.Token()
@@ -446,7 +446,7 @@ func TestConfigClientWithToken(t *testing.T) {
 	defer ts.Close()
 	conf := newConf(ts.URL)
 
-	c := conf.Client(NoContext, tok)
+	c := conf.Client(context.Background(), tok)
 	req, err := http.NewRequest("GET", ts.URL, nil)
 	if err != nil {
 		t.Error(err)