Return AccessToken by value (Azure#17836)

* Return AccessToken by value

Returning by pointer is cruft from an early design and not necessary.

* remove NewAuthenticationPolicy methods

sdk/azcore/CHANGELOG.md

@@ -17,6 +17,7 @@
 * Renamed `runtime.PageProcessor` to `runtime.PagingHandler`
 * The `arm/runtime.ProviderRepsonse` and `arm/runtime.Provider` types are no longer exported.
 * Renamed `NewRequestIdPolicy()` to `NewRequestIDPolicy()`
+* `TokenCredential.GetToken` now returns `AccessToken` by value.
 
 ### Bugs Fixed
 * When per-try timeouts are enabled, only cancel the context after the body has been read and closed.

sdk/azcore/arm/runtime/pipeline_test.go

@@ -179,15 +179,15 @@ func TestPipelineAudience(t *testing.T) {
 			t.Fatal("unexpected audience " + audience)
 		}
 		getTokenCalled := false
-		cred := mockCredential{getTokenImpl: func(ctx context.Context, options policy.TokenRequestOptions) (*azcore.AccessToken, error) {
+		cred := mockCredential{getTokenImpl: func(ctx context.Context, options policy.TokenRequestOptions) (azcore.AccessToken, error) {
 			getTokenCalled = true
 			if n := len(options.Scopes); n != 1 {
 				t.Fatalf("expected 1 scope, got %d", n)
 			}
 			if options.Scopes[0] != audience+"/.default" {
 				t.Fatalf(`unexpected scope "%s"`, options.Scopes[0])
 			}
-			return &azcore.AccessToken{Token: "...", ExpiresOn: time.Now().Add(time.Hour)}, nil
+			return azcore.AccessToken{Token: "...", ExpiresOn: time.Now().Add(time.Hour)}, nil
 		}}
 		req, err := azruntime.NewRequest(context.Background(), http.MethodGet, srv.URL())
 		if err != nil {

sdk/azcore/arm/runtime/policy_bearer_token.go

@@ -24,20 +24,20 @@ type acquiringResourceState struct {
 
 // acquire acquires or updates the resource; only one
 // thread/goroutine at a time ever calls this function
-func acquire(state acquiringResourceState) (newResource *azcore.AccessToken, newExpiration time.Time, err error) {
+func acquire(state acquiringResourceState) (newResource azcore.AccessToken, newExpiration time.Time, err error) {
 	tk, err := state.p.cred.GetToken(state.ctx, azpolicy.TokenRequestOptions{Scopes: state.p.options.Scopes})
 	if err != nil {
-		return nil, time.Time{}, err
+		return azcore.AccessToken{}, time.Time{}, err
 	}
 	return tk, tk.ExpiresOn, nil
 }
 
 // BearerTokenPolicy authorizes requests with bearer tokens acquired from a TokenCredential.
 type BearerTokenPolicy struct {
 	// mainResource is the resource to be retreived using the tenant specified in the credential
-	mainResource *shared.ExpiringResource[*azcore.AccessToken, acquiringResourceState]
+	mainResource *shared.ExpiringResource[azcore.AccessToken, acquiringResourceState]
 	// auxResources are additional resources that are required for cross-tenant applications
-	auxResources map[string]*shared.ExpiringResource[*azcore.AccessToken, acquiringResourceState]
+	auxResources map[string]*shared.ExpiringResource[azcore.AccessToken, acquiringResourceState]
 	// the following fields are read-only
 	cred    azcore.TokenCredential
 	options armpolicy.BearerTokenOptions

sdk/azcore/arm/runtime/policy_bearer_token_test.go

@@ -16,7 +16,6 @@ import (
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/arm"
 	armpolicy "github.com/Azure/azure-sdk-for-go/sdk/azcore/arm/policy"
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/internal/shared"
-	"github.com/Azure/azure-sdk-for-go/sdk/azcore/policy"
 	azpolicy "github.com/Azure/azure-sdk-for-go/sdk/azcore/policy"
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/runtime"
 	"github.com/Azure/azure-sdk-for-go/sdk/internal/mock"
@@ -30,18 +29,14 @@ const (
 )
 
 type mockCredential struct {
-	getTokenImpl func(ctx context.Context, options policy.TokenRequestOptions) (*azcore.AccessToken, error)
+	getTokenImpl func(ctx context.Context, options azpolicy.TokenRequestOptions) (azcore.AccessToken, error)
 }
 
-func (mc mockCredential) GetToken(ctx context.Context, options policy.TokenRequestOptions) (*azcore.AccessToken, error) {
+func (mc mockCredential) GetToken(ctx context.Context, options azpolicy.TokenRequestOptions) (azcore.AccessToken, error) {
 	if mc.getTokenImpl != nil {
 		return mc.getTokenImpl(ctx, options)
 	}
-	return &azcore.AccessToken{Token: "***", ExpiresOn: time.Now().Add(time.Hour)}, nil
-}
-
-func (mc mockCredential) NewAuthenticationPolicy() azpolicy.Policy {
-	return mc
+	return azcore.AccessToken{Token: "***", ExpiresOn: time.Now().Add(time.Hour)}, nil
 }
 
 func (mc mockCredential) Do(req *azpolicy.Request) (*http.Response, error) {
@@ -98,8 +93,8 @@ func TestBearerPolicy_CredentialFailGetToken(t *testing.T) {
 	defer close()
 	expectedErr := errors.New("oops")
 	failCredential := mockCredential{}
-	failCredential.getTokenImpl = func(ctx context.Context, options policy.TokenRequestOptions) (*azcore.AccessToken, error) {
-		return nil, expectedErr
+	failCredential.getTokenImpl = func(ctx context.Context, options azpolicy.TokenRequestOptions) (azcore.AccessToken, error) {
+		return azcore.AccessToken{}, expectedErr
 	}
 	b := NewBearerTokenPolicy(failCredential, nil)
 	pipeline := newTestPipeline(&azpolicy.ClientOptions{

sdk/azcore/arm/runtime/policy_register_rp_test.go

@@ -19,7 +19,6 @@ import (
 	armpolicy "github.com/Azure/azure-sdk-for-go/sdk/azcore/arm/policy"
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/cloud"
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/log"
-	"github.com/Azure/azure-sdk-for-go/sdk/azcore/policy"
 	azpolicy "github.com/Azure/azure-sdk-for-go/sdk/azcore/policy"
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/runtime"
 	"github.com/Azure/azure-sdk-for-go/sdk/internal/mock"
@@ -395,15 +394,15 @@ func TestRPRegistrationPolicyAudience(t *testing.T) {
 		},
 	}
 	getTokenCalled := false
-	cred := mockCredential{getTokenImpl: func(ctx context.Context, options policy.TokenRequestOptions) (*azcore.AccessToken, error) {
+	cred := mockCredential{getTokenImpl: func(ctx context.Context, options azpolicy.TokenRequestOptions) (azcore.AccessToken, error) {
 		getTokenCalled = true
 		if n := len(options.Scopes); n != 1 {
 			t.Fatalf("expected 1 scope, got %d", n)
 		}
 		if options.Scopes[0] != audience+"/.default" {
 			t.Fatalf(`unexpected scope "%s"`, options.Scopes[0])
 		}
-		return &azcore.AccessToken{Token: "...", ExpiresOn: time.Now().Add(time.Hour)}, nil
+		return azcore.AccessToken{Token: "...", ExpiresOn: time.Now().Add(time.Hour)}, nil
 	}}
 	opts := azpolicy.ClientOptions{Cloud: conf, Transport: srv}
 	rp, err := NewRPRegistrationPolicy(cred, &armpolicy.RegistrationOptions{ClientOptions: opts})

sdk/azcore/core.go

@@ -24,7 +24,7 @@ type AccessToken struct {
 // TokenCredential represents a credential capable of providing an OAuth token.
 type TokenCredential interface {
 	// GetToken requests an access token for the specified set of scopes.
-	GetToken(ctx context.Context, options policy.TokenRequestOptions) (*AccessToken, error)
+	GetToken(ctx context.Context, options policy.TokenRequestOptions) (AccessToken, error)
 }
 
 // holds sentinel values used to send nulls

sdk/azcore/runtime/policy_bearer_token.go

@@ -15,7 +15,7 @@ import (
 // BearerTokenPolicy authorizes requests with bearer tokens acquired from a TokenCredential.
 type BearerTokenPolicy struct {
 	// mainResource is the resource to be retreived using the tenant specified in the credential
-	mainResource *shared.ExpiringResource[*azcore.AccessToken, acquiringResourceState]
+	mainResource *shared.ExpiringResource[azcore.AccessToken, acquiringResourceState]
 	// the following fields are read-only
 	cred   azcore.TokenCredential
 	scopes []string
@@ -28,10 +28,10 @@ type acquiringResourceState struct {
 
 // acquire acquires or updates the resource; only one
 // thread/goroutine at a time ever calls this function
-func acquire(state acquiringResourceState) (newResource *azcore.AccessToken, newExpiration time.Time, err error) {
+func acquire(state acquiringResourceState) (newResource azcore.AccessToken, newExpiration time.Time, err error) {
 	tk, err := state.p.cred.GetToken(state.req.Raw().Context(), policy.TokenRequestOptions{Scopes: state.p.scopes})
 	if err != nil {
-		return nil, time.Time{}, err
+		return azcore.AccessToken{}, time.Time{}, err
 	}
 	return tk, tk.ExpiresOn, nil
 }

sdk/azcore/runtime/policy_bearer_token_test.go

@@ -25,18 +25,14 @@ const (
 )
 
 type mockCredential struct {
-	getTokenImpl func(ctx context.Context, options policy.TokenRequestOptions) (*azcore.AccessToken, error)
+	getTokenImpl func(ctx context.Context, options policy.TokenRequestOptions) (azcore.AccessToken, error)
 }
 
-func (mc mockCredential) GetToken(ctx context.Context, options policy.TokenRequestOptions) (*azcore.AccessToken, error) {
+func (mc mockCredential) GetToken(ctx context.Context, options policy.TokenRequestOptions) (azcore.AccessToken, error) {
 	if mc.getTokenImpl != nil {
 		return mc.getTokenImpl(ctx, options)
 	}
-	return &azcore.AccessToken{Token: "***", ExpiresOn: time.Now().Add(time.Hour)}, nil
-}
-
-func (mc mockCredential) NewAuthenticationPolicy() policy.Policy {
-	return mc
+	return azcore.AccessToken{Token: "***", ExpiresOn: time.Now().Add(time.Hour)}, nil
 }
 
 func (mc mockCredential) Do(req *policy.Request) (*http.Response, error) {
@@ -82,8 +78,8 @@ func TestBearerPolicy_CredentialFailGetToken(t *testing.T) {
 	defer close()
 	expectedErr := errors.New("oops")
 	failCredential := mockCredential{}
-	failCredential.getTokenImpl = func(ctx context.Context, options policy.TokenRequestOptions) (*azcore.AccessToken, error) {
-		return nil, expectedErr
+	failCredential.getTokenImpl = func(ctx context.Context, options policy.TokenRequestOptions) (azcore.AccessToken, error) {
+		return azcore.AccessToken{}, expectedErr
 	}
 	b := NewBearerTokenPolicy(failCredential, nil, nil)
 	pipeline := newTestPipeline(&policy.ClientOptions{