all: clean up Go 1.24 specific code. (#850)

Author: maciej-kisiel

docs/protocol.md

@@ -411,8 +411,7 @@ user's responsibility to wrap that function around all handlers in their server.
 - _Secure session IDs_. This SDK generates cryptographically secure session IDs by default.
 If you create your own with 
 [`ServerOptions.GetSessionID`](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk/mcp#ServerOptions.GetSessionID), it is your responsibility to ensure they are secure.
-If you are using Go 1.24 or above,
-we recommend using [`crypto/rand.Text`](https://pkg.go.dev/crypto/rand#Text) 
+We recommend using [`crypto/rand.Text`](https://pkg.go.dev/crypto/rand#Text).
 
 - _Binding session IDs to user information_. The SDK supports this mitigation through
 [`TokenInfo.UserID`](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk/auth#TokenInfo.UserID).

internal/docs/protocol.src.md

@@ -336,8 +336,7 @@ user's responsibility to wrap that function around all handlers in their server.
 - _Secure session IDs_. This SDK generates cryptographically secure session IDs by default.
 If you create your own with 
 [`ServerOptions.GetSessionID`](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk/mcp#ServerOptions.GetSessionID), it is your responsibility to ensure they are secure.
-If you are using Go 1.24 or above,
-we recommend using [`crypto/rand.Text`](https://pkg.go.dev/crypto/rand#Text) 
+We recommend using [`crypto/rand.Text`](https://pkg.go.dev/crypto/rand#Text).
 
 - _Binding session IDs to user information_. The SDK supports this mitigation through
 [`TokenInfo.UserID`](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk/auth#TokenInfo.UserID).

mcp/capabilities_go125_test.go mcp/capabilities_test.gomcp/capabilities_go125_test.go renamed to mcp/capabilities_test.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.25
-
 package mcp
 
 import (

mcp/cmd_go125_test.go

@@ -14,6 +14,7 @@ import (
 	"runtime"
 	"syscall"
 	"testing"
+	"testing/synctest"
 	"time"
 
 	"github.com/google/go-cmp/cmp"
@@ -76,47 +77,44 @@ func runCancelContextServer() {
 	}
 }
 
-// TODO: remove this test when Go 1.24 support is dropped (use go1.25 synctest version).
 func TestServerRunContextCancel(t *testing.T) {
-	server := mcp.NewServer(&mcp.Implementation{Name: "greeter", Version: "v0.0.1"}, nil)
-	mcp.AddTool(server, &mcp.Tool{Name: "greet", Description: "say hi"}, SayHi)
-
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	serverTransport, clientTransport := mcp.NewInMemoryTransports()
-
-	// run the server and capture the exit error
-	onServerExit := make(chan error)
-	go func() {
-		onServerExit <- server.Run(ctx, serverTransport)
-	}()
+	synctest.Test(t, func(t *testing.T) {
+		server := mcp.NewServer(&mcp.Implementation{Name: "greeter", Version: "v0.0.1"}, nil)
+		mcp.AddTool(server, &mcp.Tool{Name: "greet", Description: "say hi"}, SayHi)
+
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+
+		serverTransport, clientTransport := mcp.NewInMemoryTransports()
+
+		// run the server and capture the exit error
+		onServerExit := make(chan error)
+		go func() {
+			onServerExit <- server.Run(ctx, serverTransport)
+		}()
+
+		// send a ping to the server to ensure it's running
+		client := mcp.NewClient(&mcp.Implementation{Name: "client", Version: "v0.0.1"}, nil)
+		session, err := client.Connect(ctx, clientTransport, nil)
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(func() { session.Close() })
 
-	// send a ping to the server to ensure it's running
-	client := mcp.NewClient(&mcp.Implementation{Name: "client", Version: "v0.0.1"}, nil)
-	session, err := client.Connect(ctx, clientTransport, nil)
-	if err != nil {
-		t.Fatal(err)
-	}
-	t.Cleanup(func() { session.Close() })
+		if err := session.Ping(context.Background(), nil); err != nil {
+			t.Fatal(err)
+		}
 
-	if err := session.Ping(context.Background(), nil); err != nil {
-		t.Fatal(err)
-	}
+		// cancel the context to stop the server
+		cancel()
 
-	// cancel the context to stop the server
-	cancel()
+		// wait for the server to exit
 
-	// wait for the server to exit
-	// TODO: use synctest when available
-	select {
-	case <-time.After(5 * time.Second):
-		t.Fatal("server did not exit after context cancellation")
-	case err := <-onServerExit:
+		err = <-onServerExit
 		if !errors.Is(err, context.Canceled) {
 			t.Fatalf("server did not exit after context cancellation, got error: %v", err)
 		}
-	}
+	})
 }
 
 func TestServerInterrupt(t *testing.T) {

mcp/cmd_test.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
 
-//go:build (go1.24 && goexperiment.synctest) || go1.25
-
 package mcp
 
 import (
@@ -89,12 +87,9 @@ func TestServerConformance(t *testing.T) {
 			// By comparison, gopls has a complicated framework based on progress
 			// reporting and careful accounting to detect when all 'expected' work
 			// on the server is complete.
-			runSyncTest(t, func(t *testing.T) { runServerTest(t, test) })
-
-			// TODO: in 1.25, use the following instead:
-			// synctest.Test(t, func(t *testing.T) {
-			// 	runServerTest(t, test)
-			// })
+			synctest.Test(t, func(t *testing.T) {
+				runServerTest(t, test)
+			})
 		})
 	}
 }