all: modernize code (#868)

Use `go fix ./...` to modernize the code.

auth/extauth/enterprise_handler_test.go

@@ -36,7 +36,7 @@ func TestNewEnterpriseHandler_Validation(t *testing.T) {
 				AccessToken: "mock_access_token",
 				TokenType:   "Bearer",
 			}
-			return token.WithExtra(map[string]interface{}{"id_token": "mock_id_token"}), nil
+			return token.WithExtra(map[string]any{"id_token": "mock_id_token"}), nil
 		},
 	}
 
@@ -194,7 +194,7 @@ func TestNewEnterpriseHandler_Validation(t *testing.T) {
 						AccessToken: "mock_access_token",
 						TokenType:   "Bearer",
 					}
-					return token.WithExtra(map[string]interface{}{"id_token": "mock_id_token"}), nil
+					return token.WithExtra(map[string]any{"id_token": "mock_id_token"}), nil
 				},
 			},
 			wantError: "",
@@ -254,7 +254,7 @@ func TestEnterpriseHandler_Authorize_E2E(t *testing.T) {
 				AccessToken: "mock_access_token",
 				TokenType:   "Bearer",
 			}
-			return token.WithExtra(map[string]interface{}{"id_token": "mock_id_token_from_user_login"}), nil
+			return token.WithExtra(map[string]any{"id_token": "mock_id_token_from_user_login"}), nil
 		},
 	})
 	if err != nil {
@@ -305,7 +305,7 @@ func setupIdPServer(t *testing.T) *httptest.Server {
 	// OAuth/OIDC metadata endpoint - uses closure to get server URL
 	mux.HandleFunc("/.well-known/oauth-authorization-server", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
-		json.NewEncoder(w).Encode(map[string]interface{}{
+		json.NewEncoder(w).Encode(map[string]any{
 			"issuer":                           server.URL,
 			"token_endpoint":                   server.URL + "/token",
 			"authorization_endpoint":           server.URL + "/authorize",
@@ -350,7 +350,7 @@ func setupIdPServer(t *testing.T) *httptest.Server {
 
 		// Return ID-JAG (Identity Assertion JWT Authorization Grant)
 		w.Header().Set("Content-Type", "application/json")
-		json.NewEncoder(w).Encode(map[string]interface{}{
+		json.NewEncoder(w).Encode(map[string]any{
 			"access_token":      "id-jag-token-from-idp",
 			"issued_token_type": oauthex.TokenTypeIDJAG,
 			"token_type":        "N_A",
@@ -375,7 +375,7 @@ func setupMCPAuthServer(t *testing.T) *httptest.Server {
 	// OAuth metadata endpoint - uses closure to get server URL
 	mux.HandleFunc("/.well-known/oauth-authorization-server", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
-		json.NewEncoder(w).Encode(map[string]interface{}{
+		json.NewEncoder(w).Encode(map[string]any{
 			"issuer":                           server.URL,
 			"token_endpoint":                   server.URL + "/token",
 			"code_challenge_methods_supported": []string{"S256"},
@@ -412,7 +412,7 @@ func setupMCPAuthServer(t *testing.T) *httptest.Server {
 
 		// Return access token
 		w.Header().Set("Content-Type", "application/json")
-		json.NewEncoder(w).Encode(map[string]interface{}{
+		json.NewEncoder(w).Encode(map[string]any{
 			"access_token": "mcp_access_token_from_jwt_bearer",
 			"token_type":   "Bearer",
 			"expires_in":   3600,
@@ -480,7 +480,7 @@ func TestEnterpriseHandler_TokenSource_BeforeAuthorization(t *testing.T) {
 				AccessToken: "mock_access_token",
 				TokenType:   "Bearer",
 			}
-			return token.WithExtra(map[string]interface{}{"id_token": "mock_id_token"}), nil
+			return token.WithExtra(map[string]any{"id_token": "mock_id_token"}), nil
 		},
 	})
 	if err != nil {

auth/extauth/oidc_login_test.go

@@ -327,7 +327,7 @@ func createMockOIDCServer(t *testing.T) *httptest.Server {
 		// Handle OIDC discovery
 		if r.URL.Path == "/.well-known/openid-configuration" {
 			w.Header().Set("Content-Type", "application/json")
-			json.NewEncoder(w).Encode(map[string]interface{}{
+			json.NewEncoder(w).Encode(map[string]any{
 				"issuer":                           serverURL,
 				"authorization_endpoint":           serverURL + "/authorize",
 				"token_endpoint":                   serverURL + "/token",
@@ -351,7 +351,7 @@ func createMockOIDCServerWithToken(t *testing.T) *httptest.Server {
 		// Handle OIDC discovery
 		if r.URL.Path == "/.well-known/openid-configuration" {
 			w.Header().Set("Content-Type", "application/json")
-			json.NewEncoder(w).Encode(map[string]interface{}{
+			json.NewEncoder(w).Encode(map[string]any{
 				"issuer":                           serverURL,
 				"authorization_endpoint":           serverURL + "/authorize",
 				"token_endpoint":                   serverURL + "/token",
@@ -376,7 +376,7 @@ func createMockOIDCServerWithToken(t *testing.T) *httptest.Server {
 			// Create mock ID token (JWT)
 			now := time.Now().Unix()
 			idToken := fmt.Sprintf("eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.%s.mock-signature",
-				base64EncodeClaims(map[string]interface{}{
+				base64EncodeClaims(map[string]any{
 					"iss":   serverURL,
 					"sub":   "test-user",
 					"aud":   "test-client",
@@ -386,7 +386,7 @@ func createMockOIDCServerWithToken(t *testing.T) *httptest.Server {
 				}))
 			// Return token response
 			w.Header().Set("Content-Type", "application/json")
-			json.NewEncoder(w).Encode(map[string]interface{}{
+			json.NewEncoder(w).Encode(map[string]any{
 				"access_token":  "mock-access-token",
 				"token_type":    "Bearer",
 				"expires_in":    3600,
@@ -402,7 +402,7 @@ func createMockOIDCServerWithToken(t *testing.T) *httptest.Server {
 }
 
 // base64EncodeClaims encodes JWT claims for testing.
-func base64EncodeClaims(claims map[string]interface{}) string {
+func base64EncodeClaims(claims map[string]any) string {
 	claimsJSON, _ := json.Marshal(claims)
 	return base64.RawURLEncoding.EncodeToString(claimsJSON)
 }

examples/client/loadtest/main.go

@@ -69,9 +69,7 @@ func main() {
 	// Run the test.
 	var wg sync.WaitGroup
 	for range *workers {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
+		wg.Go(func() {
 			client := mcp.NewClient(&mcp.Implementation{Name: "mcp-client", Version: "v1.0.0"}, nil)
 			cs, err := client.Connect(parentCtx, &mcp.StreamableClientTransport{Endpoint: args[0]}, nil)
 			if err != nil {
@@ -108,7 +106,7 @@ func main() {
 					}
 				}
 			}
-		}()
+		})
 	}
 	wg.Wait()
 	stop() // restore the interrupt signal

examples/server/distributed/main.go

@@ -89,16 +89,14 @@ func parent() {
 		cmd.Env = append(os.Environ(), fmt.Sprintf("%s=%s", childPortVar, port))
 		cmd.Stderr = os.Stderr
 
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
+		wg.Go(func() {
 			log.Printf("starting child %d at %s", i, childURL)
 			if err := cmd.Run(); err != nil && ctx.Err() == nil {
 				log.Printf("child %d failed: %v", i, err)
 			} else {
 				log.Printf("child %d exited gracefully", i)
 			}
-		}()
+		})
 	}
 
 	// Start a reverse proxy that round-robin's requests to each backend.
@@ -116,13 +114,11 @@ func parent() {
 		},
 	}
 
-	wg.Add(1)
-	go func() {
-		defer wg.Done()
+	wg.Go(func() {
 		if err := server.ListenAndServe(); err != nil && ctx.Err() == nil {
 			log.Printf("Server failed: %v", err)
 		}
-	}()
+	})
 
 	log.Printf("Serving at %s (CTRL-C to cancel)", *httpAddr)
 

internal/oauthtest/fake_authorization_server.go

@@ -282,7 +282,7 @@ func (s *FakeAuthorizationServer) handleToken(w http.ResponseWriter, r *http.Req
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]interface{}{
+	json.NewEncoder(w).Encode(map[string]any{
 		"access_token": "test_access_token",
 		"token_type":   "Bearer",
 		"expires_in":   3600,

mcp/cmd_test.go

@@ -200,8 +200,7 @@ func TestStdioContextCancellation(t *testing.T) {
 func TestCmdTransport(t *testing.T) {
 	requireExec(t)
 
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := t.Context()
 
 	cmd := createServerCommand(t, "default")
 
@@ -287,8 +286,7 @@ func TestCommandTransportTerminateDuration(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			ctx, cancel := context.WithCancel(context.Background())
-			defer cancel()
+			ctx := t.Context()
 
 			// Use a command that won't exit when stdin is closed
 			cmd := exec.Command("sleep", "20")

mcp/content_nil_test.go

@@ -22,8 +22,8 @@ func TestContentUnmarshalNil(t *testing.T) {
 	tests := []struct {
 		name    string
 		json    string
-		content interface{}
-		want    interface{}
+		content any
+		want    any
 	}{
 		{
 			name:    "CallToolResult nil Content",
@@ -83,7 +83,7 @@ func TestContentUnmarshalNilWithDifferentTypes(t *testing.T) {
 	tests := []struct {
 		name        string
 		json        string
-		content     interface{}
+		content     any
 		expectError bool
 	}{
 		{
@@ -145,7 +145,7 @@ func TestContentUnmarshalNilWithEmptyContent(t *testing.T) {
 	tests := []struct {
 		name        string
 		json        string
-		content     interface{}
+		content     any
 		expectError bool
 	}{
 		{
@@ -186,7 +186,7 @@ func TestContentUnmarshalNilWithInvalidContent(t *testing.T) {
 	tests := []struct {
 		name        string
 		json        string
-		content     interface{}
+		content     any
 		expectError bool
 	}{
 		{

mcp/mcp_test.go

@@ -676,13 +676,11 @@ func TestServerClosing(t *testing.T) {
 
 	ctx := context.Background()
 	var wg sync.WaitGroup
-	wg.Add(1)
-	go func() {
+	wg.Go(func() {
 		if err := cs.Wait(); err != nil {
 			t.Errorf("server connection failed: %v", err)
 		}
-		wg.Done()
-	}()
+	})
 	if _, err := cs.CallTool(ctx, &CallToolParams{
 		Name:      "greet",
 		Arguments: map[string]any{"Name": "user"},

mcp/schema_cache_test.go

@@ -194,7 +194,7 @@ func TestAddToolWithSharedCache(t *testing.T) {
 	}
 
 	// Simulate stateless server pattern: new server per request, shared cache.
-	for i := 0; i < 3; i++ {
+	for range 3 {
 		s := NewServer(&Implementation{Name: "test", Version: "1.0"}, &ServerOptions{
 			SchemaCache: cache,
 		})

mcp/streamable_bench_test.go

@@ -5,7 +5,6 @@
 package mcp_test
 
 import (
-	"context"
 	"flag"
 	"log"
 	"net/http"
@@ -51,8 +50,7 @@ func BenchmarkStreamableServing(b *testing.B) {
 	httpServer := httptest.NewServer(handler)
 	defer httpServer.Close()
 
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := b.Context()
 	session, err := mcp.NewClient(testImpl, nil).Connect(ctx, &mcp.StreamableClientTransport{Endpoint: httpServer.URL}, nil)
 	if err != nil {
 		b.Fatal(err)
@@ -84,8 +82,7 @@ func BenchmarkStreamableServing_BadSessions(b *testing.B) {
 	httpServer := httptest.NewServer(handler)
 	defer httpServer.Close()
 
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := b.Context()
 
 	if *streamableHeap != "" {
 		writeHeap := func(file string) {

mcp/streamable_test.go

@@ -108,9 +108,7 @@ func TestStreamableTransports(t *testing.T) {
 				}
 				// Now, spin off a goroutine that runs after the sampling request, to
 				// check behavior when the client request has completed.
-				sampleWG.Add(1)
-				go func() {
-					defer sampleWG.Done()
+				sampleWG.Go(func() {
 					<-sampleDone
 					// Test that sampling requests in the tool context fail outside of
 					// tool handling, but succeed on the background context.
@@ -120,7 +118,7 @@ func TestStreamableTransports(t *testing.T) {
 					} {
 						testSample(test)
 					}
-				}()
+				})
 				return &CallToolResult{}, nil, nil
 			})
 
@@ -268,9 +266,7 @@ func TestStreamableConcurrentHandling(t *testing.T) {
 	client := NewClient(testImpl, nil)
 	var wg sync.WaitGroup
 	for range 100 {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
+		wg.Go(func() {
 			clientSession, err := client.Connect(ctx, &StreamableClientTransport{Endpoint: httpServer.URL}, nil)
 			if err != nil {
 				t.Errorf("Connect failed: %v", err)
@@ -287,7 +283,7 @@ func TestStreamableConcurrentHandling(t *testing.T) {
 					t.Errorf("got count %d, want %d", got, i)
 				}
 			}
-		}()
+		})
 	}
 	wg.Wait()
 }
@@ -1293,9 +1289,7 @@ func testStreamableHandler(t *testing.T, handler http.Handler, requests []stream
 		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 
 		var wg sync.WaitGroup
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
+		wg.Go(func() {
 
 			for m := range out {
 				if req, ok := m.(*jsonrpc.Request); ok && req.IsCall() {
@@ -1315,7 +1309,7 @@ func testStreamableHandler(t *testing.T, handler http.Handler, requests []stream
 					cancel()
 				}
 			}
-		}()
+		})
 
 		gotSessionID, gotStatusCode, gotBody, err := request.do(ctx, httpServer.URL, sessionID.Load().(string), out)
 
@@ -1353,11 +1347,9 @@ func testStreamableHandler(t *testing.T, handler http.Handler, requests []stream
 	var wg sync.WaitGroup
 	for i, request := range requests {
 		if request.async || request.onRequest > 0 {
-			wg.Add(1)
-			go func() {
-				defer wg.Done()
+			wg.Go(func() {
 				doStep(t, i, request)
-			}()
+			})
 		} else {
 			doStep(t, i, request)
 		}
@@ -2071,18 +2063,15 @@ func TestStreamableSessionTimeout(t *testing.T) {
 	// Spin up two goroutines, each making a request every 10ms. These requests
 	// should keep the server from timing out.
 	var wg sync.WaitGroup
-	wg.Add(2)
 	for range 2 {
-		go func() {
-			defer wg.Done()
-
+		wg.Go(func() {
 			for range 20 {
 				if _, err := session.ListTools(ctx, nil); err != nil {
 					t.Errorf("ListTools failed: %v", err)
 				}
 				time.Sleep(10 * time.Millisecond)
 			}
-		}()
+		})
 	}
 
 	wg.Wait()
@@ -2154,8 +2143,7 @@ data: keepalive
 	}
 
 	// Create a minimal streamableClientConn for testing
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := t.Context()
 
 	incoming := make(chan jsonrpc.Message, 10)
 	done := make(chan struct{})

oauthex/token_exchange_test.go

@@ -97,7 +97,7 @@ func TestExchangeToken(t *testing.T) {
 		}
 
 		// Return successful token exchange response per SEP-990 Section 4.2
-		resp := map[string]interface{}{
+		resp := map[string]any{
 			"issued_token_type": TokenTypeIDJAG,
 			"access_token":      "fake-id-jag-token",
 			"token_type":        "N_A",