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mcp: add 2026-07-28 to the supported protocol versions (#1020)

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This PR adds the protocol version `2026-07-28` to the list of supported
protocol versions and fixes legacy tests hardcoding the legacy protocol
version for those use cases.
This commit is contained in:
Guglielmo Colombo 2026-06-24 12:02:56 +02:00 • committed by GitHub
commit 7f4aa4a0ce
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GPG key ID: B5690EEEBB952194
1 changed files with 355 additions and 218 deletions
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132
mcp/streamable_client_test.go
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@ -160,7 +160,8 @@ var (
Logging: &LoggingCapabilities{},
Tools: &ToolCapabilities{ListChanged: true},
},
ProtocolVersion: latestProtocolVersion,
// Pin negotiated version to 2025-11-25
ProtocolVersion: protocolVersion20251125,
ServerInfo: &Implementation{Name: "testServer", Version: "v1.0.0"},
}
initResp = resp(1, initResult, nil)
@ -193,13 +194,13 @@ func TestStreamableClientTransportLifecycle(t *testing.T) {
},
{"POST", "123", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"GET", "123", "", ""}: {
header: header{
"Content-Type": "text/event-stream",
},
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"DELETE", "123", "", ""}: {},
},
@ -210,7 +211,10 @@ func TestStreamableClientTransportLifecycle(t *testing.T) {
transport := &StreamableClientTransport{Endpoint: httpServer.URL}
client := NewClient(testImpl, nil)
session, err := client.Connect(ctx, transport, nil)
// Pin to 2025-11-25: the fixture's canned initialize response uses
// hardcoded id=1, which only matches when initialize is the first
// request. Under 2026-07-28 the client probes server/discover first.
session, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err != nil {
t.Fatalf("client.Connect() failed: %v", err)
}
@ -244,7 +248,7 @@ func TestStreamableClientRedundantDelete(t *testing.T) {
},
{"POST", "123", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"GET", "123", "", ""}: {
status: http.StatusMethodNotAllowed,
@ -260,7 +264,10 @@ func TestStreamableClientRedundantDelete(t *testing.T) {
transport := &StreamableClientTransport{Endpoint: httpServer.URL}
client := NewClient(testImpl, nil)
session, err := client.Connect(ctx, transport, nil)
// Pin to 2025-11-25: the fixture's canned initialize response uses
// hardcoded id=1, which only matches when initialize is the first
// request. Under 2026-07-28 the client probes server/discover first.
session, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err != nil {
t.Fatalf("client.Connect() failed: %v", err)
}
@ -307,14 +314,14 @@ func TestStreamableClientGETHandling(t *testing.T) {
},
{"POST", "123", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"GET", "123", "", ""}: {
header: header{
"Content-Type": test.contentType,
},
status: test.status,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"DELETE", "123", "", ""}: {optional: true},
},
@ -324,7 +331,9 @@ func TestStreamableClientGETHandling(t *testing.T) {
transport := &StreamableClientTransport{Endpoint: httpServer.URL}
client := NewClient(testImpl, nil)
session, err := client.Connect(ctx, transport, nil)
session, err := client.Connect(ctx, transport, &ClientSessionOptions{
protocolVersion: protocolVersion20251125,
})
if err == nil {
defer session.Close()
}
@ -376,14 +385,14 @@ func TestStreamableClientStrictness(t *testing.T) {
},
{"POST", "123", notificationInitialized, ""}: {
status: test.initializedStatus,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"GET", "123", "", ""}: {
header: header{
"Content-Type": "text/event-stream",
},
status: test.getStatus,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"POST", "123", methodListTools, ""}: {
header: header{
@ -401,7 +410,11 @@ func TestStreamableClientStrictness(t *testing.T) {
transport := &StreamableClientTransport{Endpoint: httpServer.URL, strict: test.strict}
client := NewClient(testImpl, nil)
session, err := client.Connect(ctx, transport, nil)
// Pin to 2025-11-25: the fixture's canned initialize response
// uses hardcoded id=1, which only matches when initialize is
// the first request. Under 2026-07-28 the client probes
// server/discover first.
session, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if (err != nil) != test.wantConnectError {
t.Errorf("client.Connect() returned error %v; want error: %t", err, test.wantConnectError)
}
@ -441,7 +454,7 @@ func TestStreamableClientUnresumableRequest(t *testing.T) {
transport := &StreamableClientTransport{Endpoint: httpServer.URL}
client := NewClient(testImpl, nil)
cs, err := client.Connect(ctx, transport, nil)
cs, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err == nil {
cs.Close()
t.Fatalf("Connect succeeded unexpectedly")
@ -515,7 +528,7 @@ func TestStreamableClientResumption_Cancelled(t *testing.T) {
},
{"POST", "123", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"GET", "123", "", ""}: {
header: header{
@ -558,7 +571,11 @@ data: { "jsonrpc": "2.0", "method": "notifications/message", "params": { "level"
transport := &StreamableClientTransport{Endpoint: httpServer.URL}
client := NewClient(testImpl, nil)
cs, err := client.Connect(ctx, transport, nil)
// Pin to 2025-11-25: the fixture's canned initialize response
// uses hardcoded id=1, which only matches when initialize is
// the first request. Under 2026-07-28 the client probes
// server/discover first.
cs, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err != nil {
t.Fatal(err)
}
@ -658,7 +675,7 @@ func TestStreamableClientTransientErrors(t *testing.T) {
},
{"POST", "123", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"GET", "123", "", ""}: {
status: http.StatusMethodNotAllowed,
@ -686,7 +703,11 @@ func TestStreamableClientTransientErrors(t *testing.T) {
transport := &StreamableClientTransport{Endpoint: httpServer.URL}
client := NewClient(testImpl, nil)
session, err := client.Connect(ctx, transport, nil)
// Pin to 2025-11-25: the fixture's canned initialize response
// uses hardcoded id=1, which only matches when initialize is
// the first request. Under 2026-07-28 the client probes
// server/discover first.
session, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err != nil {
t.Fatalf("Connect failed: %v", err)
}
@ -747,7 +768,7 @@ func TestStreamableClientRetryWithoutProgress(t *testing.T) {
},
{"POST", "test-session", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"GET", "test-session", "", ""}: {
// Disable standalone SSE stream to simplify the test.
@ -789,7 +810,10 @@ data: {"jsonrpc":"2.0","method":"notifications/message","params":{"level":"info"
MaxRetries: maxRetries,
}
client := NewClient(testImpl, nil)
session, err := client.Connect(ctx, transport, nil)
// Pin to 2025-11-25: the fixture's canned initialize response uses
// hardcoded id=1, which only matches when initialize is the first
// request. Under 2026-07-28 the client probes server/discover first.
session, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err != nil {
t.Fatalf("Connect failed: %v", err)
}
@ -850,13 +874,13 @@ func TestStreamableClientDisableStandaloneSSE(t *testing.T) {
},
{"POST", "123", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
getRequestKey: {
header: header{
"Content-Type": "text/event-stream",
},
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
optional: !test.expectGETRequest,
},
{"DELETE", "123", "", ""}: {
@ -873,7 +897,11 @@ func TestStreamableClientDisableStandaloneSSE(t *testing.T) {
DisableStandaloneSSE: test.disableStandaloneSSE,
}
client := NewClient(testImpl, nil)
session, err := client.Connect(ctx, transport, nil)
// Pin to 2025-11-25: the fixture's canned initialize response
// uses hardcoded id=1, which only matches when initialize is
// the first request. Under 2026-07-28 the client probes
// server/discover first.
session, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err != nil {
t.Fatalf("client.Connect() failed: %v", err)
}
@ -967,7 +995,7 @@ func TestStreamableClientOAuth_AuthorizationHeader(t *testing.T) {
},
{"POST", "123", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"GET", "123", "", ""}: {
header: header{
@ -991,7 +1019,10 @@ func TestStreamableClientOAuth_AuthorizationHeader(t *testing.T) {
OAuthHandler: oauthHandler,
}
client := NewClient(testImpl, nil)
session, err := client.Connect(ctx, transport, nil)
// Pin to 2025-11-25: the fixture's canned initialize response uses
// hardcoded id=1, which only matches when initialize is the first
// request. Under 2026-07-28 the client probes server/discover first.
session, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err != nil {
t.Fatalf("client.Connect() failed: %v", err)
}
@ -1253,13 +1284,6 @@ var discoverResult = &DiscoverResult{
func TestStreamableClientConnect_DiscoverSuccess(t *testing.T) {
ctx := context.Background()
// Temporarily enable 2026-07-28 support in the SDK for this test
oldSupported := supportedProtocolVersions
supportedProtocolVersions = append([]string{protocolVersion20260728}, supportedProtocolVersions...)
t.Cleanup(func() {
supportedProtocolVersions = oldSupported
})
var (
gotDiscoverMu sync.Mutex
gotDiscover *jsonrpc.Request
@ -1378,11 +1402,11 @@ func TestStreamableClientConnect_DiscoverMethodNotFound(t *testing.T) {
},
{"POST", "fallback", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"GET", "fallback", "", ""}: {
header: header{"Content-Type": "text/event-stream"},
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
optional: true,
},
{"DELETE", "fallback", "", ""}: {optional: true},
@ -1394,14 +1418,16 @@ func TestStreamableClientConnect_DiscoverMethodNotFound(t *testing.T) {
transport := &StreamableClientTransport{Endpoint: httpServer.URL}
client := NewClient(testImpl, nil)
session, err := client.Connect(ctx, transport, nil)
session, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err != nil {
t.Fatalf("Connect: %v", err)
}
defer session.Close()
if got := session.InitializeResult().ProtocolVersion; got != latestProtocolVersion {
t.Errorf("InitializeResult.ProtocolVersion = %q, want %q (initialize fallback)", got, latestProtocolVersion)
// The fallback initialize explicitly requests protocolVersion20251125
// (see client.go), so the server negotiates that version.
if got := session.InitializeResult().ProtocolVersion; got != protocolVersion20251125 {
t.Errorf("InitializeResult.ProtocolVersion = %q, want %q (initialize fallback)", got, protocolVersion20251125)
}
}
@ -1443,11 +1469,11 @@ func TestStreamableClientConnect_DiscoverUnsupportedVersion(t *testing.T) {
},
{"POST", "fallback", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"GET", "fallback", "", ""}: {
header: header{"Content-Type": "text/event-stream"},
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
optional: true,
},
{"DELETE", "fallback", "", ""}: {optional: true},
@ -1459,14 +1485,16 @@ func TestStreamableClientConnect_DiscoverUnsupportedVersion(t *testing.T) {
transport := &StreamableClientTransport{Endpoint: httpServer.URL}
client := NewClient(testImpl, nil)
session, err := client.Connect(ctx, transport, nil)
session, err := client.Connect(ctx, transport, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err != nil {
t.Fatalf("Connect: %v", err)
}
defer session.Close()
if got := session.InitializeResult().ProtocolVersion; got != latestProtocolVersion {
t.Errorf("InitializeResult.ProtocolVersion = %q, want %q (initialize fallback)", got, latestProtocolVersion)
// The fallback initialize explicitly requests protocolVersion20251125
// (see client.go), so the server negotiates that version.
if got := session.InitializeResult().ProtocolVersion; got != protocolVersion20251125 {
t.Errorf("InitializeResult.ProtocolVersion = %q, want %q (initialize fallback)", got, protocolVersion20251125)
}
}
@ -1503,7 +1531,7 @@ func TestStreamableClientConnect_DiscoverMethodNotFoundVPre(t *testing.T) {
},
{"POST", "fallback", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"DELETE", "fallback", "", ""}: {optional: true},
},
@ -1523,8 +1551,10 @@ func TestStreamableClientConnect_DiscoverMethodNotFoundVPre(t *testing.T) {
}
defer session.Close()
if got := session.InitializeResult().ProtocolVersion; got != latestProtocolVersion {
t.Errorf("InitializeResult.ProtocolVersion = %q, want %q (initialize fallback)", got, latestProtocolVersion)
// The fallback initialize explicitly requests protocolVersion20251125
// (see client.go), so the server negotiates that version.
if got := session.InitializeResult().ProtocolVersion; got != protocolVersion20251125 {
t.Errorf("InitializeResult.ProtocolVersion = %q, want %q (initialize fallback)", got, protocolVersion20251125)
}
}
@ -1558,7 +1588,7 @@ func TestStreamableClientConnect_DiscoverUnsupportedVersionVPre(t *testing.T) {
},
{"POST", "fallback", notificationInitialized, ""}: {
status: http.StatusAccepted,
wantProtocolVersion: latestProtocolVersion,
wantProtocolVersion: protocolVersion20251125,
},
{"DELETE", "fallback", "", ""}: {optional: true},
},
@ -1578,8 +1608,10 @@ func TestStreamableClientConnect_DiscoverUnsupportedVersionVPre(t *testing.T) {
}
defer session.Close()
if got := session.InitializeResult().ProtocolVersion; got != latestProtocolVersion {
t.Errorf("InitializeResult.ProtocolVersion = %q, want %q (initialize fallback)", got, latestProtocolVersion)
// The fallback initialize explicitly requests protocolVersion20251125
// (see client.go), so the server negotiates that version.
if got := session.InitializeResult().ProtocolVersion; got != protocolVersion20251125 {
t.Errorf("InitializeResult.ProtocolVersion = %q, want %q (initialize fallback)", got, protocolVersion20251125)
}
}
@ -1590,12 +1622,6 @@ func TestStreamableClientConnect_DiscoverUnsupportedVersionVPre(t *testing.T) {
func TestStreamableClientConnect_DiscoverUnsupportedVersionNegotiation(t *testing.T) {
ctx := context.Background()
oldSupported := supportedProtocolVersions
supportedProtocolVersions = append([]string{protocolVersion20260728}, supportedProtocolVersions...)
t.Cleanup(func() {
supportedProtocolVersions = oldSupported
})
const unsupportedClientVersion = "2099-12-31"
var discoverCalls atomic.Int32