From 45a30f9868714d0afea39d3d948ec1dbbfadfc1c Mon Sep 17 00:00:00 2001
From: Joshua Kim <20001595+joshua-kim@users.noreply.github.com>
Date: Thu, 4 Jul 2024 14:46:57 -0400
Subject: [PATCH 1/2] Send AppErrors from p2p SDK (#2753)

Signed-off-by: Joshua Kim <20001595+joshua-kim@users.noreply.github.com>
Co-authored-by: Stephen Buttolph <stephen@avalabs.org>
---
 go.mod                                |   2 +-
 go.sum                                |   4 +-
 network/p2p/error.go                  |  33 ++++++++
 network/p2p/gossip/handler.go         |  16 ++--
 network/p2p/handler.go                |  18 ++---
 network/p2p/handler_test.go           |   3 +-
 network/p2p/network_test.go           | 108 +++++++++++++++++++++++---
 network/p2p/router.go                 |  12 ++-
 network/p2p/throttler_handler.go      |  12 +--
 network/p2p/throttler_handler_test.go |   3 +-
 vms/avm/network/gossip.go             |   3 +-
 vms/platformvm/network/gossip.go      |   3 +-
 vms/platformvm/vm_test.go             |   3 +
 13 files changed, 174 insertions(+), 46 deletions(-)
 create mode 100644 network/p2p/error.go

diff --git a/go.mod b/go.mod
index 3c251d2fc54c..4eef73478aa4 100644
--- a/go.mod
+++ b/go.mod
@@ -10,7 +10,7 @@ require (
 	github.com/DataDog/zstd v1.5.2
 	github.com/NYTimes/gziphandler v1.1.1
 	github.com/antithesishq/antithesis-sdk-go v0.3.8
-	github.com/ava-labs/coreth v0.13.6-rc.1
+	github.com/ava-labs/coreth v0.13.6-rc.1.0.20240702201359-ba2ce5367874
 	github.com/ava-labs/ledger-avalanche/go v0.0.0-20240610153809-9c955cc90a95
 	github.com/btcsuite/btcd/btcutil v1.1.3
 	github.com/cockroachdb/pebble v0.0.0-20230928194634-aa077af62593
diff --git a/go.sum b/go.sum
index 49e67f0213d6..0642e3c0e5fa 100644
--- a/go.sum
+++ b/go.sum
@@ -62,8 +62,8 @@ github.com/allegro/bigcache v1.2.1-0.20190218064605-e24eb225f156/go.mod h1:Cb/ax
 github.com/antithesishq/antithesis-sdk-go v0.3.8 h1:OvGoHxIcOXFJLyn9IJQ5DzByZ3YVAWNBc394ObzDRb8=
 github.com/antithesishq/antithesis-sdk-go v0.3.8/go.mod h1:IUpT2DPAKh6i/YhSbt6Gl3v2yvUZjmKncl7U91fup7E=
 github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=
-github.com/ava-labs/coreth v0.13.6-rc.1 h1:gRXRokmu0WOlPqyx+mTLWB655e8/w++u6qFcq9Mo7qA=
-github.com/ava-labs/coreth v0.13.6-rc.1/go.mod h1:vm9T8qzP7RLo/jR2MKkliPfaiGgWeEpu/PG6fvvPmog=
+github.com/ava-labs/coreth v0.13.6-rc.1.0.20240702201359-ba2ce5367874 h1:aTDg0jvO07EvUvBYebmLO25bffe1DAaZZPPL0ooGhIA=
+github.com/ava-labs/coreth v0.13.6-rc.1.0.20240702201359-ba2ce5367874/go.mod h1:VhNDxZBsqZQQaUTmIkzdyY8UicIsoTDXlRmPaPL9lkA=
 github.com/ava-labs/ledger-avalanche/go v0.0.0-20240610153809-9c955cc90a95 h1:dOVbtdnZL++pENdTCNZ1nu41eYDQkTML4sWebDnnq8c=
 github.com/ava-labs/ledger-avalanche/go v0.0.0-20240610153809-9c955cc90a95/go.mod h1:pJxaT9bUgeRNVmNRgtCHb7sFDIRKy7CzTQVi8gGNT6g=
 github.com/aymerick/raymond v2.0.3-0.20180322193309-b565731e1464+incompatible/go.mod h1:osfaiScAUVup+UC9Nfq76eWqDhXlp+4UYaA8uhTBO6g=
diff --git a/network/p2p/error.go b/network/p2p/error.go
new file mode 100644
index 000000000000..07207319a041
--- /dev/null
+++ b/network/p2p/error.go
@@ -0,0 +1,33 @@
+// Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+package p2p
+
+import "github.com/ava-labs/avalanchego/snow/engine/common"
+
+var (
+	// ErrUnexpected should be used to indicate that a request failed due to a
+	// generic error
+	ErrUnexpected = &common.AppError{
+		Code:    -1,
+		Message: "unexpected error",
+	}
+	// ErrUnregisteredHandler should be used to indicate that a request failed
+	// due to it not matching a registered handler
+	ErrUnregisteredHandler = &common.AppError{
+		Code:    -2,
+		Message: "unregistered handler",
+	}
+	// ErrNotValidator should be used to indicate that a request failed due to
+	// the requesting peer not being a validator
+	ErrNotValidator = &common.AppError{
+		Code:    -3,
+		Message: "not a validator",
+	}
+	// ErrThrottled should be used to indicate that a request failed due to the
+	// requesting peer exceeding a rate limit
+	ErrThrottled = &common.AppError{
+		Code:    -4,
+		Message: "throttled",
+	}
+)
diff --git a/network/p2p/gossip/handler.go b/network/p2p/gossip/handler.go
index 7f5f7b380ed7..1205a5f2b7df 100644
--- a/network/p2p/gossip/handler.go
+++ b/network/p2p/gossip/handler.go
@@ -11,6 +11,7 @@ import (
 
 	"github.com/ava-labs/avalanchego/ids"
 	"github.com/ava-labs/avalanchego/network/p2p"
+	"github.com/ava-labs/avalanchego/snow/engine/common"
 	"github.com/ava-labs/avalanchego/utils/bloom"
 	"github.com/ava-labs/avalanchego/utils/logging"
 )
@@ -43,10 +44,10 @@ type Handler[T Gossipable] struct {
 	targetResponseSize int
 }
 
-func (h Handler[T]) AppRequest(_ context.Context, _ ids.NodeID, _ time.Time, requestBytes []byte) ([]byte, error) {
+func (h Handler[T]) AppRequest(_ context.Context, _ ids.NodeID, _ time.Time, requestBytes []byte) ([]byte, *common.AppError) {
 	filter, salt, err := ParseAppRequest(requestBytes)
 	if err != nil {
-		return nil, err
+		return nil, p2p.ErrUnexpected
 	}
 
 	responseSize := 0
@@ -73,14 +74,19 @@ func (h Handler[T]) AppRequest(_ context.Context, _ ids.NodeID, _ time.Time, req
 		return responseSize <= h.targetResponseSize
 	})
 	if err != nil {
-		return nil, err
+		return nil, p2p.ErrUnexpected
 	}
 
 	if err := h.metrics.observeMessage(sentPullLabels, len(gossipBytes), responseSize); err != nil {
-		return nil, err
+		return nil, p2p.ErrUnexpected
 	}
 
-	return MarshalAppResponse(gossipBytes)
+	response, err := MarshalAppResponse(gossipBytes)
+	if err != nil {
+		return nil, p2p.ErrUnexpected
+	}
+
+	return response, nil
 }
 
 func (h Handler[_]) AppGossip(_ context.Context, nodeID ids.NodeID, gossipBytes []byte) {
diff --git a/network/p2p/handler.go b/network/p2p/handler.go
index ed005fb761c0..3afeb3eb9a46 100644
--- a/network/p2p/handler.go
+++ b/network/p2p/handler.go
@@ -5,7 +5,6 @@ package p2p
 
 import (
 	"context"
-	"errors"
 	"time"
 
 	"go.uber.org/zap"
@@ -17,8 +16,6 @@ import (
 )
 
 var (
-	ErrNotValidator = errors.New("not a validator")
-
 	_ Handler = (*NoOpHandler)(nil)
 	_ Handler = (*TestHandler)(nil)
 	_ Handler = (*ValidatorHandler)(nil)
@@ -33,13 +30,14 @@ type Handler interface {
 		gossipBytes []byte,
 	)
 	// AppRequest is called when handling an AppRequest message.
-	// Returns the bytes for the response corresponding to [requestBytes]
+	// Sends a response with the response corresponding to [requestBytes] or
+	// an application-defined error.
 	AppRequest(
 		ctx context.Context,
 		nodeID ids.NodeID,
 		deadline time.Time,
 		requestBytes []byte,
-	) ([]byte, error)
+	) ([]byte, *common.AppError)
 	// CrossChainAppRequest is called when handling a CrossChainAppRequest
 	// message.
 	// Returns the bytes for the response corresponding to [requestBytes]
@@ -56,7 +54,7 @@ type NoOpHandler struct{}
 
 func (NoOpHandler) AppGossip(context.Context, ids.NodeID, []byte) {}
 
-func (NoOpHandler) AppRequest(context.Context, ids.NodeID, time.Time, []byte) ([]byte, error) {
+func (NoOpHandler) AppRequest(context.Context, ids.NodeID, time.Time, []byte) ([]byte, *common.AppError) {
 	return nil, nil
 }
 
@@ -95,7 +93,7 @@ func (v ValidatorHandler) AppGossip(ctx context.Context, nodeID ids.NodeID, goss
 	v.handler.AppGossip(ctx, nodeID, gossipBytes)
 }
 
-func (v ValidatorHandler) AppRequest(ctx context.Context, nodeID ids.NodeID, deadline time.Time, requestBytes []byte) ([]byte, error) {
+func (v ValidatorHandler) AppRequest(ctx context.Context, nodeID ids.NodeID, deadline time.Time, requestBytes []byte) ([]byte, *common.AppError) {
 	if !v.validatorSet.Has(ctx, nodeID) {
 		return nil, ErrNotValidator
 	}
@@ -128,7 +126,7 @@ func (r *responder) AppRequest(ctx context.Context, nodeID ids.NodeID, requestID
 			zap.Binary("message", request),
 			zap.Error(err),
 		)
-		return nil
+		return r.sender.SendAppError(ctx, nodeID, requestID, err.Code, err.Message)
 	}
 
 	return r.sender.SendAppResponse(ctx, nodeID, requestID, appResponse)
@@ -155,7 +153,7 @@ func (r *responder) CrossChainAppRequest(ctx context.Context, chainID ids.ID, re
 
 type TestHandler struct {
 	AppGossipF            func(ctx context.Context, nodeID ids.NodeID, gossipBytes []byte)
-	AppRequestF           func(ctx context.Context, nodeID ids.NodeID, deadline time.Time, requestBytes []byte) ([]byte, error)
+	AppRequestF           func(ctx context.Context, nodeID ids.NodeID, deadline time.Time, requestBytes []byte) ([]byte, *common.AppError)
 	CrossChainAppRequestF func(ctx context.Context, chainID ids.ID, deadline time.Time, requestBytes []byte) ([]byte, error)
 }
 
@@ -167,7 +165,7 @@ func (t TestHandler) AppGossip(ctx context.Context, nodeID ids.NodeID, gossipByt
 	t.AppGossipF(ctx, nodeID, gossipBytes)
 }
 
-func (t TestHandler) AppRequest(ctx context.Context, nodeID ids.NodeID, deadline time.Time, requestBytes []byte) ([]byte, error) {
+func (t TestHandler) AppRequest(ctx context.Context, nodeID ids.NodeID, deadline time.Time, requestBytes []byte) ([]byte, *common.AppError) {
 	if t.AppRequestF == nil {
 		return nil, nil
 	}
diff --git a/network/p2p/handler_test.go b/network/p2p/handler_test.go
index 0633b70f00a8..f933215ca6ee 100644
--- a/network/p2p/handler_test.go
+++ b/network/p2p/handler_test.go
@@ -11,6 +11,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/snow/engine/common"
 	"github.com/ava-labs/avalanchego/utils/logging"
 	"github.com/ava-labs/avalanchego/utils/set"
 )
@@ -79,7 +80,7 @@ func TestValidatorHandlerAppRequest(t *testing.T) {
 		name         string
 		validatorSet ValidatorSet
 		nodeID       ids.NodeID
-		expected     error
+		expected     *common.AppError
 	}{
 		{
 			name:         "message dropped",
diff --git a/network/p2p/network_test.go b/network/p2p/network_test.go
index 5339a6eeb315..5346a9255a00 100644
--- a/network/p2p/network_test.go
+++ b/network/p2p/network_test.go
@@ -43,7 +43,7 @@ func TestMessageRouting(t *testing.T) {
 			require.Equal(wantNodeID, nodeID)
 			require.Equal(wantMsg, msg)
 		},
-		AppRequestF: func(_ context.Context, nodeID ids.NodeID, _ time.Time, msg []byte) ([]byte, error) {
+		AppRequestF: func(_ context.Context, nodeID ids.NodeID, _ time.Time, msg []byte) ([]byte, *common.AppError) {
 			appRequestCalled = true
 			require.Equal(wantNodeID, nodeID)
 			require.Equal(wantMsg, msg)
@@ -352,7 +352,7 @@ func TestCrossChainAppRequestFailed(t *testing.T) {
 }
 
 // Messages for unregistered handlers should be dropped gracefully
-func TestMessageForUnregisteredHandler(t *testing.T) {
+func TestAppGossipMessageForUnregisteredHandler(t *testing.T) {
 	tests := []struct {
 		name string
 		msg  []byte
@@ -379,26 +379,110 @@ func TestMessageForUnregisteredHandler(t *testing.T) {
 				AppGossipF: func(context.Context, ids.NodeID, []byte) {
 					require.Fail("should not be called")
 				},
-				AppRequestF: func(context.Context, ids.NodeID, time.Time, []byte) ([]byte, error) {
-					require.Fail("should not be called")
-					return nil, nil
-				},
-				CrossChainAppRequestF: func(context.Context, ids.ID, time.Time, []byte) ([]byte, error) {
+			}
+			network, err := NewNetwork(logging.NoLog{}, nil, prometheus.NewRegistry(), "")
+			require.NoError(err)
+			require.NoError(network.AddHandler(handlerID, handler))
+			require.NoError(network.AppGossip(ctx, ids.EmptyNodeID, tt.msg))
+		})
+	}
+}
+
+// An unregistered handler should gracefully drop messages by responding
+// to the requester with a common.AppError
+func TestAppRequestMessageForUnregisteredHandler(t *testing.T) {
+	tests := []struct {
+		name string
+		msg  []byte
+	}{
+		{
+			name: "nil",
+			msg:  nil,
+		},
+		{
+			name: "empty",
+			msg:  []byte{},
+		},
+		{
+			name: "non-empty",
+			msg:  []byte("foobar"),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			require := require.New(t)
+			ctx := context.Background()
+			handler := &TestHandler{
+				AppRequestF: func(context.Context, ids.NodeID, time.Time, []byte) ([]byte, *common.AppError) {
 					require.Fail("should not be called")
 					return nil, nil
 				},
 			}
-			network, err := NewNetwork(logging.NoLog{}, nil, prometheus.NewRegistry(), "")
+
+			wantNodeID := ids.GenerateTestNodeID()
+			wantRequestID := uint32(111)
+
+			done := make(chan struct{})
+			sender := &common.SenderTest{}
+			sender.SendAppErrorF = func(_ context.Context, nodeID ids.NodeID, requestID uint32, errorCode int32, errorMessage string) error {
+				defer close(done)
+
+				require.Equal(wantNodeID, nodeID)
+				require.Equal(wantRequestID, requestID)
+				require.Equal(ErrUnregisteredHandler.Code, errorCode)
+				require.Equal(ErrUnregisteredHandler.Message, errorMessage)
+
+				return nil
+			}
+			network, err := NewNetwork(logging.NoLog{}, sender, prometheus.NewRegistry(), "")
 			require.NoError(err)
 			require.NoError(network.AddHandler(handlerID, handler))
 
-			require.NoError(network.AppRequest(ctx, ids.EmptyNodeID, 0, time.Time{}, tt.msg))
-			require.NoError(network.AppGossip(ctx, ids.EmptyNodeID, tt.msg))
-			require.NoError(network.CrossChainAppRequest(ctx, ids.Empty, 0, time.Time{}, tt.msg))
+			require.NoError(network.AppRequest(ctx, wantNodeID, wantRequestID, time.Time{}, tt.msg))
+			<-done
 		})
 	}
 }
 
+// A handler that errors should send an AppError to the requesting peer
+func TestAppError(t *testing.T) {
+	require := require.New(t)
+	ctx := context.Background()
+	appError := &common.AppError{
+		Code:    123,
+		Message: "foo",
+	}
+	handler := &TestHandler{
+		AppRequestF: func(context.Context, ids.NodeID, time.Time, []byte) ([]byte, *common.AppError) {
+			return nil, appError
+		},
+	}
+
+	wantNodeID := ids.GenerateTestNodeID()
+	wantRequestID := uint32(111)
+
+	done := make(chan struct{})
+	sender := &common.SenderTest{}
+	sender.SendAppErrorF = func(_ context.Context, nodeID ids.NodeID, requestID uint32, errorCode int32, errorMessage string) error {
+		defer close(done)
+
+		require.Equal(wantNodeID, nodeID)
+		require.Equal(wantRequestID, requestID)
+		require.Equal(appError.Code, errorCode)
+		require.Equal(appError.Message, errorMessage)
+
+		return nil
+	}
+	network, err := NewNetwork(logging.NoLog{}, sender, prometheus.NewRegistry(), "")
+	require.NoError(err)
+	require.NoError(network.AddHandler(handlerID, handler))
+	msg := PrefixMessage(ProtocolPrefix(handlerID), []byte("message"))
+
+	require.NoError(network.AppRequest(ctx, wantNodeID, wantRequestID, time.Time{}, msg))
+	<-done
+}
+
 // A response or timeout for a request we never made should return an error
 func TestResponseForUnrequestedRequest(t *testing.T) {
 	tests := []struct {
@@ -427,7 +511,7 @@ func TestResponseForUnrequestedRequest(t *testing.T) {
 				AppGossipF: func(context.Context, ids.NodeID, []byte) {
 					require.Fail("should not be called")
 				},
-				AppRequestF: func(context.Context, ids.NodeID, time.Time, []byte) ([]byte, error) {
+				AppRequestF: func(context.Context, ids.NodeID, time.Time, []byte) ([]byte, *common.AppError) {
 					require.Fail("should not be called")
 					return nil, nil
 				},
diff --git a/network/p2p/router.go b/network/p2p/router.go
index 6d4c7efe4d47..8f099ddb0b64 100644
--- a/network/p2p/router.go
+++ b/network/p2p/router.go
@@ -128,14 +128,18 @@ func (r *router) AppRequest(ctx context.Context, nodeID ids.NodeID, requestID ui
 	start := time.Now()
 	parsedMsg, handler, handlerID, ok := r.parse(request)
 	if !ok {
-		r.log.Debug("failed to process message",
+		r.log.Debug("received message for unregistered handler",
 			zap.Stringer("messageOp", message.AppRequestOp),
 			zap.Stringer("nodeID", nodeID),
 			zap.Uint32("requestID", requestID),
 			zap.Time("deadline", deadline),
 			zap.Binary("message", request),
 		)
-		return nil
+
+		// Send an error back to the requesting peer. Invalid requests that we
+		// cannot parse a handler id for are handled the same way as requests
+		// for which we do not have a registered handler.
+		return r.sender.SendAppError(ctx, nodeID, requestID, ErrUnregisteredHandler.Code, ErrUnregisteredHandler.Message)
 	}
 
 	// call the corresponding handler and send back a response to nodeID
@@ -209,7 +213,7 @@ func (r *router) AppGossip(ctx context.Context, nodeID ids.NodeID, gossip []byte
 	start := time.Now()
 	parsedMsg, handler, handlerID, ok := r.parse(gossip)
 	if !ok {
-		r.log.Debug("failed to process message",
+		r.log.Debug("received message for unregistered handler",
 			zap.Stringer("messageOp", message.AppGossipOp),
 			zap.Stringer("nodeID", nodeID),
 			zap.Binary("message", gossip),
@@ -244,7 +248,7 @@ func (r *router) CrossChainAppRequest(
 	start := time.Now()
 	parsedMsg, handler, handlerID, ok := r.parse(msg)
 	if !ok {
-		r.log.Debug("failed to process message",
+		r.log.Debug("received message for unregistered handler",
 			zap.Stringer("messageOp", message.CrossChainAppRequestOp),
 			zap.Stringer("chainID", chainID),
 			zap.Uint32("requestID", requestID),
diff --git a/network/p2p/throttler_handler.go b/network/p2p/throttler_handler.go
index df0200482ef6..2718f733223c 100644
--- a/network/p2p/throttler_handler.go
+++ b/network/p2p/throttler_handler.go
@@ -5,20 +5,16 @@ package p2p
 
 import (
 	"context"
-	"errors"
-	"fmt"
 	"time"
 
 	"go.uber.org/zap"
 
 	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/snow/engine/common"
 	"github.com/ava-labs/avalanchego/utils/logging"
 )
 
-var (
-	ErrThrottled         = errors.New("throttled")
-	_            Handler = (*ThrottlerHandler)(nil)
-)
+var _ Handler = (*ThrottlerHandler)(nil)
 
 func NewThrottlerHandler(handler Handler, throttler Throttler, log logging.Logger) *ThrottlerHandler {
 	return &ThrottlerHandler{
@@ -46,9 +42,9 @@ func (t ThrottlerHandler) AppGossip(ctx context.Context, nodeID ids.NodeID, goss
 	t.handler.AppGossip(ctx, nodeID, gossipBytes)
 }
 
-func (t ThrottlerHandler) AppRequest(ctx context.Context, nodeID ids.NodeID, deadline time.Time, requestBytes []byte) ([]byte, error) {
+func (t ThrottlerHandler) AppRequest(ctx context.Context, nodeID ids.NodeID, deadline time.Time, requestBytes []byte) ([]byte, *common.AppError) {
 	if !t.throttler.Handle(nodeID) {
-		return nil, fmt.Errorf("dropping message from %s: %w", nodeID, ErrThrottled)
+		return nil, ErrThrottled
 	}
 
 	return t.handler.AppRequest(ctx, nodeID, deadline, requestBytes)
diff --git a/network/p2p/throttler_handler_test.go b/network/p2p/throttler_handler_test.go
index 1f5a07069d8e..52dd964f1013 100644
--- a/network/p2p/throttler_handler_test.go
+++ b/network/p2p/throttler_handler_test.go
@@ -11,6 +11,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/snow/engine/common"
 	"github.com/ava-labs/avalanchego/utils/logging"
 )
 
@@ -57,7 +58,7 @@ func TestThrottlerHandlerAppRequest(t *testing.T) {
 	tests := []struct {
 		name        string
 		Throttler   Throttler
-		expectedErr error
+		expectedErr *common.AppError
 	}{
 		{
 			name:      "not throttled",
diff --git a/vms/avm/network/gossip.go b/vms/avm/network/gossip.go
index 6ea5f1448485..131cc51688fa 100644
--- a/vms/avm/network/gossip.go
+++ b/vms/avm/network/gossip.go
@@ -14,6 +14,7 @@ import (
 	"github.com/ava-labs/avalanchego/ids"
 	"github.com/ava-labs/avalanchego/network/p2p"
 	"github.com/ava-labs/avalanchego/network/p2p/gossip"
+	"github.com/ava-labs/avalanchego/snow/engine/common"
 	"github.com/ava-labs/avalanchego/utils/logging"
 	"github.com/ava-labs/avalanchego/vms/avm/txs"
 	"github.com/ava-labs/avalanchego/vms/txs/mempool"
@@ -51,7 +52,7 @@ func (t txGossipHandler) AppRequest(
 	nodeID ids.NodeID,
 	deadline time.Time,
 	requestBytes []byte,
-) ([]byte, error) {
+) ([]byte, *common.AppError) {
 	return t.appRequestHandler.AppRequest(ctx, nodeID, deadline, requestBytes)
 }
 
diff --git a/vms/platformvm/network/gossip.go b/vms/platformvm/network/gossip.go
index c8cfefceed48..7e6e7adc341c 100644
--- a/vms/platformvm/network/gossip.go
+++ b/vms/platformvm/network/gossip.go
@@ -14,6 +14,7 @@ import (
 	"github.com/ava-labs/avalanchego/ids"
 	"github.com/ava-labs/avalanchego/network/p2p"
 	"github.com/ava-labs/avalanchego/network/p2p/gossip"
+	"github.com/ava-labs/avalanchego/snow/engine/common"
 	"github.com/ava-labs/avalanchego/utils/logging"
 	"github.com/ava-labs/avalanchego/vms/platformvm/txs"
 	"github.com/ava-labs/avalanchego/vms/txs/mempool"
@@ -51,7 +52,7 @@ func (t txGossipHandler) AppRequest(
 	nodeID ids.NodeID,
 	deadline time.Time,
 	requestBytes []byte,
-) ([]byte, error) {
+) ([]byte, *common.AppError) {
 	return t.appRequestHandler.AppRequest(ctx, nodeID, deadline, requestBytes)
 }
 
diff --git a/vms/platformvm/vm_test.go b/vms/platformvm/vm_test.go
index 24fa707a8e32..9153ee6548bf 100644
--- a/vms/platformvm/vm_test.go
+++ b/vms/platformvm/vm_test.go
@@ -291,6 +291,9 @@ func defaultVM(t *testing.T, f fork) (*VM, *txstest.WalletFactory, database.Data
 	appSender.SendAppGossipF = func(context.Context, common.SendConfig, []byte) error {
 		return nil
 	}
+	appSender.SendAppErrorF = func(context.Context, ids.NodeID, uint32, int32, string) error {
+		return nil
+	}
 
 	dynamicConfigBytes := []byte(`{"network":{"max-validator-set-staleness":0}}`)
 	require.NoError(vm.Initialize(

From 2af3890f79d49aacd2de4c090433fdf614398dc9 Mon Sep 17 00:00:00 2001
From: Arran Schlosberg <519948+ARR4N@users.noreply.github.com>
Date: Mon, 8 Jul 2024 17:41:21 +0100
Subject: [PATCH 2/2] build(tests): require `//go:build test` tag if importing
 test packages outside of `_test.go` files (#3173)

---
 .golangci.yml                                 |  5 ++++
 .vscode/settings.json                         | 11 ++++++++
 cache/test_cacher.go                          |  2 ++
 chains/atomic/test_shared_memory.go           |  2 ++
 codec/test_codec.go                           |  2 ++
 database/benchmark_database.go                |  2 ++
 database/test_database.go                     |  2 ++
 ids/test_aliases.go                           |  2 ++
 scripts/build_fuzz.sh                         |  2 +-
 scripts/build_test.sh                         |  2 +-
 scripts/lint.sh                               | 27 ++++++++++++++++++-
 scripts/tests.e2e.existing.sh                 |  2 +-
 scripts/tests.e2e.sh                          |  4 +--
 scripts/tests.upgrade.sh                      |  2 +-
 snow/consensus/snowball/test_snowflake.go     |  2 ++
 .../avalanche/bootstrap/queue/test_job.go     |  2 ++
 .../avalanche/bootstrap/queue/test_parser.go  |  2 ++
 snow/engine/avalanche/vertex/test_builder.go  |  2 ++
 snow/engine/avalanche/vertex/test_manager.go  |  2 ++
 snow/engine/avalanche/vertex/test_parser.go   |  2 ++
 snow/engine/avalanche/vertex/test_storage.go  |  2 ++
 snow/engine/avalanche/vertex/test_vm.go       |  2 ++
 snow/engine/common/test_bootstrap_tracker.go  |  2 ++
 snow/engine/common/test_bootstrapper.go       |  2 ++
 snow/engine/common/test_engine.go             |  2 ++
 snow/engine/common/test_sender.go             |  2 ++
 snow/engine/common/test_timer.go              |  2 ++
 snow/engine/common/test_vm.go                 |  2 ++
 snow/engine/snowman/block/test_batched_vm.go  |  2 ++
 .../snowman/block/test_state_summary.go       |  2 ++
 .../snowman/block/test_state_syncable_vm.go   |  2 ++
 snow/engine/snowman/block/test_vm.go          |  2 ++
 snow/networking/benchlist/test_benchable.go   |  2 ++
 .../networking/sender/test_external_sender.go |  2 ++
 snow/snowtest/snowtest.go                     |  2 ++
 snow/validators/test_state.go                 |  3 +++
 tests/e2e/banff/suites.go                     |  2 ++
 tests/e2e/c/dynamic_fees.go                   |  2 ++
 tests/e2e/c/interchain_workflow.go            |  2 ++
 tests/e2e/faultinjection/duplicate_node_id.go |  2 ++
 tests/e2e/p/interchain_workflow.go            |  2 ++
 tests/e2e/p/permissionless_subnets.go         |  2 ++
 tests/e2e/p/staking_rewards.go                |  2 ++
 tests/e2e/p/validator_sets.go                 |  2 ++
 tests/e2e/p/workflow.go                       |  2 ++
 tests/e2e/vms/xsvm.go                         |  2 ++
 tests/e2e/x/interchain_workflow.go            |  2 ++
 tests/e2e/x/transfer/virtuous.go              |  2 ++
 tests/fixture/e2e/env.go                      |  2 ++
 tests/fixture/e2e/helpers.go                  |  2 ++
 vms/platformvm/warp/test_signer.go            |  2 ++
 wallet/subnet/primary/common/test_utxos.go    |  2 ++
 52 files changed, 137 insertions(+), 7 deletions(-)
 create mode 100644 .vscode/settings.json

diff --git a/.golangci.yml b/.golangci.yml
index a1991abd29aa..1809a5fa6609 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -15,6 +15,11 @@ run:
   # By default, it isn't set.
   modules-download-mode: readonly
 
+  # Include non-test files tagged as test-only.
+  # Context: https://github.com/ava-labs/avalanchego/pull/3173
+  build-tags:
+    - test
+
 output:
   # Make issues output unique by line.
   # Default: true
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 000000000000..0abd38ef2982
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,11 @@
+{
+    "gopls": {
+        "build.buildFlags": [
+            // Context: https://github.com/ava-labs/avalanchego/pull/3173
+            // Without this tag, the language server won't build the test-only
+            // code in non-_test.go files.
+            "--tags='test'",
+        ],
+    },
+    "go.testTags": "test",
+}
\ No newline at end of file
diff --git a/cache/test_cacher.go b/cache/test_cacher.go
index 2e85502e4a55..35b1ad9c1711 100644
--- a/cache/test_cacher.go
+++ b/cache/test_cacher.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package cache
 
 import (
diff --git a/chains/atomic/test_shared_memory.go b/chains/atomic/test_shared_memory.go
index 82b1cbeff3a5..f1c7b44ae30c 100644
--- a/chains/atomic/test_shared_memory.go
+++ b/chains/atomic/test_shared_memory.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package atomic
 
 import (
diff --git a/codec/test_codec.go b/codec/test_codec.go
index 2dc8b3e2add9..974168dd4829 100644
--- a/codec/test_codec.go
+++ b/codec/test_codec.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package codec
 
 import (
diff --git a/database/benchmark_database.go b/database/benchmark_database.go
index 43af10db1c2b..479035c126cb 100644
--- a/database/benchmark_database.go
+++ b/database/benchmark_database.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package database
 
 import (
diff --git a/database/test_database.go b/database/test_database.go
index e35a98dca36f..4e5bc174ae85 100644
--- a/database/test_database.go
+++ b/database/test_database.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package database
 
 import (
diff --git a/ids/test_aliases.go b/ids/test_aliases.go
index ce9991f5f737..3943fce16023 100644
--- a/ids/test_aliases.go
+++ b/ids/test_aliases.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package ids
 
 import "github.com/stretchr/testify/require"
diff --git a/scripts/build_fuzz.sh b/scripts/build_fuzz.sh
index 49378e2e0878..520b244bc631 100755
--- a/scripts/build_fuzz.sh
+++ b/scripts/build_fuzz.sh
@@ -28,7 +28,7 @@ do
         echo "Fuzzing $func in $file"
         parentDir=$(dirname "$file")
         # If any of the fuzz tests fail, return exit code 1
-        if ! go test "$parentDir" -run="$func" -fuzz="$func" -fuzztime="${fuzzTime}"s; then
+        if ! go test -tags test "$parentDir" -run="$func" -fuzz="$func" -fuzztime="${fuzzTime}"s; then
             failed=true
         fi
     done
diff --git a/scripts/build_test.sh b/scripts/build_test.sh
index c0c9b72e3230..4a7cbd04f746 100755
--- a/scripts/build_test.sh
+++ b/scripts/build_test.sh
@@ -18,4 +18,4 @@ fi
 TEST_TARGETS="$(eval "go list ./... ${EXCLUDED_TARGETS}")"
 
 # shellcheck disable=SC2086
-go test -shuffle=on -race -timeout="${TIMEOUT:-120s}" -coverprofile="coverage.out" -covermode="atomic" ${TEST_TARGETS}
+go test -tags test -shuffle=on -race -timeout="${TIMEOUT:-120s}" -coverprofile="coverage.out" -covermode="atomic" ${TEST_TARGETS}
diff --git a/scripts/lint.sh b/scripts/lint.sh
index 9fb23ae325be..7f2111d6f96e 100755
--- a/scripts/lint.sh
+++ b/scripts/lint.sh
@@ -29,7 +29,7 @@ fi
 # by default, "./scripts/lint.sh" runs all lint tests
 # to run only "license_header" test
 # TESTS='license_header' ./scripts/lint.sh
-TESTS=${TESTS:-"golangci_lint license_header require_error_is_no_funcs_as_params single_import interface_compliance_nil require_no_error_inline_func"}
+TESTS=${TESTS:-"golangci_lint license_header require_error_is_no_funcs_as_params single_import interface_compliance_nil require_no_error_inline_func import_testing_only_in_tests"}
 
 function test_golangci_lint {
   go install -v github.com/golangci/golangci-lint/cmd/golangci-lint@v1.58.1
@@ -86,6 +86,31 @@ function test_interface_compliance_nil {
   fi
 }
 
+function test_import_testing_only_in_tests {
+  ROOT=$( git rev-parse --show-toplevel )
+  NON_TEST_GO_FILES=$( find "${ROOT}" -iname '*.go' ! -iname '*_test.go');
+
+  IMPORT_TESTING=$( echo "${NON_TEST_GO_FILES}" | xargs grep -lP '^\s*(import\s+)?"testing"');
+  IMPORT_TESTIFY=$( echo "${NON_TEST_GO_FILES}" | xargs grep -l '"github.com/stretchr/testify');
+  # TODO(arr4n): send a PR to add support for build tags in `mockgen` and then enable this.
+  # IMPORT_GOMOCK=$( echo "${NON_TEST_GO_FILES}" | xargs grep -l '"go.uber.org/mock');
+  HAVE_TEST_LOGIC=$( printf "%s\n%s" "${IMPORT_TESTING}" "${IMPORT_TESTIFY}" );
+
+  TAGGED_AS_TEST=$( echo "${NON_TEST_GO_FILES}" | xargs grep -lP '^\/\/go:build\s+(.+(,|\s+))?test[,\s]?');
+
+  # -3 suppresses files that have test logic and have the "test" build tag
+  # -2 suppresses files that are tagged despite not having detectable test logic
+  UNTAGGED=$( comm -23 <( echo "${HAVE_TEST_LOGIC}" | sort -u ) <( echo "${TAGGED_AS_TEST}" | sort -u ) );
+  if [ -z "${UNTAGGED}" ];
+  then
+    return 0;
+  fi
+
+  echo "Non-test Go files importing test-only packages MUST have '//go:build test' tag:";
+  echo "${UNTAGGED}";
+  return 1;
+}
+
 function run {
   local test="${1}"
   shift 1
diff --git a/scripts/tests.e2e.existing.sh b/scripts/tests.e2e.existing.sh
index 4b28fc1ad271..dbe41ec003d1 100755
--- a/scripts/tests.e2e.existing.sh
+++ b/scripts/tests.e2e.existing.sh
@@ -22,7 +22,7 @@ function print_separator {
 function cleanup {
   print_separator
   echo "cleaning up reusable network"
-  ginkgo -v ./tests/e2e/e2e.test -- --stop-network
+  ginkgo -v --tags test ./tests/e2e/e2e.test -- --stop-network
 }
 trap cleanup EXIT
 
diff --git a/scripts/tests.e2e.sh b/scripts/tests.e2e.sh
index 564116b40fda..efc1889af5ac 100755
--- a/scripts/tests.e2e.sh
+++ b/scripts/tests.e2e.sh
@@ -23,7 +23,7 @@ source ./scripts/constants.sh
 echo "building e2e.test"
 # to install the ginkgo binary (required for test build and run)
 go install -v github.com/onsi/ginkgo/v2/ginkgo@v2.13.1
-ACK_GINKGO_RC=true ginkgo build ./tests/e2e
+ACK_GINKGO_RC=true ginkgo build --tags test ./tests/e2e
 ./tests/e2e/e2e.test --help
 
 # Enable subnet testing by building xsvm
@@ -57,4 +57,4 @@ fi
 
 #################################
 # - Execute in random order to identify unwanted dependency
-ginkgo ${GINKGO_ARGS} -v --randomize-all ./tests/e2e/e2e.test -- "${E2E_ARGS[@]}" "${@}"
+ginkgo ${GINKGO_ARGS} -v --tags test --randomize-all ./tests/e2e/e2e.test -- "${E2E_ARGS[@]}" "${@}"
diff --git a/scripts/tests.upgrade.sh b/scripts/tests.upgrade.sh
index 8cc158d87d49..1adab23248b9 100755
--- a/scripts/tests.upgrade.sh
+++ b/scripts/tests.upgrade.sh
@@ -66,7 +66,7 @@ source ./scripts/constants.sh
 echo "building upgrade.test"
 # to install the ginkgo binary (required for test build and run)
 go install -v github.com/onsi/ginkgo/v2/ginkgo@v2.13.1
-ACK_GINKGO_RC=true ginkgo build ./tests/upgrade
+ACK_GINKGO_RC=true ginkgo build --tags test ./tests/upgrade
 ./tests/upgrade/upgrade.test --help
 
 #################################
diff --git a/snow/consensus/snowball/test_snowflake.go b/snow/consensus/snowball/test_snowflake.go
index 78ce95b27e3d..8688ee82c09b 100644
--- a/snow/consensus/snowball/test_snowflake.go
+++ b/snow/consensus/snowball/test_snowflake.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package snowball
 
 import "testing"
diff --git a/snow/engine/avalanche/bootstrap/queue/test_job.go b/snow/engine/avalanche/bootstrap/queue/test_job.go
index 91a370b96d81..8884ee0a2357 100644
--- a/snow/engine/avalanche/bootstrap/queue/test_job.go
+++ b/snow/engine/avalanche/bootstrap/queue/test_job.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package queue
 
 import (
diff --git a/snow/engine/avalanche/bootstrap/queue/test_parser.go b/snow/engine/avalanche/bootstrap/queue/test_parser.go
index 1cc1cfd2973f..2787973d267e 100644
--- a/snow/engine/avalanche/bootstrap/queue/test_parser.go
+++ b/snow/engine/avalanche/bootstrap/queue/test_parser.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package queue
 
 import (
diff --git a/snow/engine/avalanche/vertex/test_builder.go b/snow/engine/avalanche/vertex/test_builder.go
index 534629372249..90d603fc10a9 100644
--- a/snow/engine/avalanche/vertex/test_builder.go
+++ b/snow/engine/avalanche/vertex/test_builder.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package vertex
 
 import (
diff --git a/snow/engine/avalanche/vertex/test_manager.go b/snow/engine/avalanche/vertex/test_manager.go
index 6954161cdd46..22bb6ce696eb 100644
--- a/snow/engine/avalanche/vertex/test_manager.go
+++ b/snow/engine/avalanche/vertex/test_manager.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package vertex
 
 import "testing"
diff --git a/snow/engine/avalanche/vertex/test_parser.go b/snow/engine/avalanche/vertex/test_parser.go
index 2ee10add6090..d3c2b0b8d8a2 100644
--- a/snow/engine/avalanche/vertex/test_parser.go
+++ b/snow/engine/avalanche/vertex/test_parser.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package vertex
 
 import (
diff --git a/snow/engine/avalanche/vertex/test_storage.go b/snow/engine/avalanche/vertex/test_storage.go
index 8e0b8bc1e84d..3e00dbdda879 100644
--- a/snow/engine/avalanche/vertex/test_storage.go
+++ b/snow/engine/avalanche/vertex/test_storage.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package vertex
 
 import (
diff --git a/snow/engine/avalanche/vertex/test_vm.go b/snow/engine/avalanche/vertex/test_vm.go
index ee17c8b13ae0..49948b81d516 100644
--- a/snow/engine/avalanche/vertex/test_vm.go
+++ b/snow/engine/avalanche/vertex/test_vm.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package vertex
 
 import (
diff --git a/snow/engine/common/test_bootstrap_tracker.go b/snow/engine/common/test_bootstrap_tracker.go
index 2e940f1a43b1..59aea61c5549 100644
--- a/snow/engine/common/test_bootstrap_tracker.go
+++ b/snow/engine/common/test_bootstrap_tracker.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package common
 
 import (
diff --git a/snow/engine/common/test_bootstrapper.go b/snow/engine/common/test_bootstrapper.go
index 259fcb07fb3e..ae1aef57abdf 100644
--- a/snow/engine/common/test_bootstrapper.go
+++ b/snow/engine/common/test_bootstrapper.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package common
 
 import (
diff --git a/snow/engine/common/test_engine.go b/snow/engine/common/test_engine.go
index e07352d43713..80470fa0509c 100644
--- a/snow/engine/common/test_engine.go
+++ b/snow/engine/common/test_engine.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package common
 
 import (
diff --git a/snow/engine/common/test_sender.go b/snow/engine/common/test_sender.go
index e3cb44165c54..9f4e5689751d 100644
--- a/snow/engine/common/test_sender.go
+++ b/snow/engine/common/test_sender.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package common
 
 import (
diff --git a/snow/engine/common/test_timer.go b/snow/engine/common/test_timer.go
index 6da0d9251712..c189dd15c237 100644
--- a/snow/engine/common/test_timer.go
+++ b/snow/engine/common/test_timer.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package common
 
 import (
diff --git a/snow/engine/common/test_vm.go b/snow/engine/common/test_vm.go
index 828b49f5e1fe..bbad058e13ff 100644
--- a/snow/engine/common/test_vm.go
+++ b/snow/engine/common/test_vm.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package common
 
 import (
diff --git a/snow/engine/snowman/block/test_batched_vm.go b/snow/engine/snowman/block/test_batched_vm.go
index e5d654ec4a87..92e766b86137 100644
--- a/snow/engine/snowman/block/test_batched_vm.go
+++ b/snow/engine/snowman/block/test_batched_vm.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package block
 
 import (
diff --git a/snow/engine/snowman/block/test_state_summary.go b/snow/engine/snowman/block/test_state_summary.go
index 7287cff10120..5921acb3e8dc 100644
--- a/snow/engine/snowman/block/test_state_summary.go
+++ b/snow/engine/snowman/block/test_state_summary.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package block
 
 import (
diff --git a/snow/engine/snowman/block/test_state_syncable_vm.go b/snow/engine/snowman/block/test_state_syncable_vm.go
index f1eeb9606642..2bf5fe425941 100644
--- a/snow/engine/snowman/block/test_state_syncable_vm.go
+++ b/snow/engine/snowman/block/test_state_syncable_vm.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package block
 
 import (
diff --git a/snow/engine/snowman/block/test_vm.go b/snow/engine/snowman/block/test_vm.go
index 503d3f9d4851..cdbeabacc4f1 100644
--- a/snow/engine/snowman/block/test_vm.go
+++ b/snow/engine/snowman/block/test_vm.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package block
 
 import (
diff --git a/snow/networking/benchlist/test_benchable.go b/snow/networking/benchlist/test_benchable.go
index dabfab564829..57a611a3765a 100644
--- a/snow/networking/benchlist/test_benchable.go
+++ b/snow/networking/benchlist/test_benchable.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package benchlist
 
 import (
diff --git a/snow/networking/sender/test_external_sender.go b/snow/networking/sender/test_external_sender.go
index 3d5e688492b9..da91edb54db1 100644
--- a/snow/networking/sender/test_external_sender.go
+++ b/snow/networking/sender/test_external_sender.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package sender
 
 import (
diff --git a/snow/snowtest/snowtest.go b/snow/snowtest/snowtest.go
index 3cacc8e873bf..be08ae75b21e 100644
--- a/snow/snowtest/snowtest.go
+++ b/snow/snowtest/snowtest.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package snowtest
 
 import (
diff --git a/snow/validators/test_state.go b/snow/validators/test_state.go
index ee4102cf7194..378f3e8a8780 100644
--- a/snow/validators/test_state.go
+++ b/snow/validators/test_state.go
@@ -1,6 +1,9 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+// TODO: https://github.com/ava-labs/avalanchego/issues/3174
+//go:build test || !test
+
 package validators
 
 import (
diff --git a/tests/e2e/banff/suites.go b/tests/e2e/banff/suites.go
index b6da324c98ea..1f61eaa7ad92 100644
--- a/tests/e2e/banff/suites.go
+++ b/tests/e2e/banff/suites.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 // Implements tests for the banff network upgrade.
 package banff
 
diff --git a/tests/e2e/c/dynamic_fees.go b/tests/e2e/c/dynamic_fees.go
index c3dda77b985c..8a65ca910667 100644
--- a/tests/e2e/c/dynamic_fees.go
+++ b/tests/e2e/c/dynamic_fees.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package c
 
 import (
diff --git a/tests/e2e/c/interchain_workflow.go b/tests/e2e/c/interchain_workflow.go
index bfb342818a5f..89330ccd68a7 100644
--- a/tests/e2e/c/interchain_workflow.go
+++ b/tests/e2e/c/interchain_workflow.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package c
 
 import (
diff --git a/tests/e2e/faultinjection/duplicate_node_id.go b/tests/e2e/faultinjection/duplicate_node_id.go
index 288583c7e09b..13daafad2b86 100644
--- a/tests/e2e/faultinjection/duplicate_node_id.go
+++ b/tests/e2e/faultinjection/duplicate_node_id.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package faultinjection
 
 import (
diff --git a/tests/e2e/p/interchain_workflow.go b/tests/e2e/p/interchain_workflow.go
index 548c82ac1211..c74a7d6757eb 100644
--- a/tests/e2e/p/interchain_workflow.go
+++ b/tests/e2e/p/interchain_workflow.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package p
 
 import (
diff --git a/tests/e2e/p/permissionless_subnets.go b/tests/e2e/p/permissionless_subnets.go
index dc92bdd60d5c..4e91569e9256 100644
--- a/tests/e2e/p/permissionless_subnets.go
+++ b/tests/e2e/p/permissionless_subnets.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package p
 
 import (
diff --git a/tests/e2e/p/staking_rewards.go b/tests/e2e/p/staking_rewards.go
index e988cf43c2c4..7e8178c53a32 100644
--- a/tests/e2e/p/staking_rewards.go
+++ b/tests/e2e/p/staking_rewards.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package p
 
 import (
diff --git a/tests/e2e/p/validator_sets.go b/tests/e2e/p/validator_sets.go
index a3f3e1e9f075..6ecbe42d1452 100644
--- a/tests/e2e/p/validator_sets.go
+++ b/tests/e2e/p/validator_sets.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package p
 
 import (
diff --git a/tests/e2e/p/workflow.go b/tests/e2e/p/workflow.go
index 3708c6b82c0a..c4e597d27263 100644
--- a/tests/e2e/p/workflow.go
+++ b/tests/e2e/p/workflow.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package p
 
 import (
diff --git a/tests/e2e/vms/xsvm.go b/tests/e2e/vms/xsvm.go
index 5d3557acd405..b7ac0dc0b0b9 100644
--- a/tests/e2e/vms/xsvm.go
+++ b/tests/e2e/vms/xsvm.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package vms
 
 import (
diff --git a/tests/e2e/x/interchain_workflow.go b/tests/e2e/x/interchain_workflow.go
index ecc52f41f032..c096b6e39228 100644
--- a/tests/e2e/x/interchain_workflow.go
+++ b/tests/e2e/x/interchain_workflow.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package x
 
 import (
diff --git a/tests/e2e/x/transfer/virtuous.go b/tests/e2e/x/transfer/virtuous.go
index 58a0351ba123..5e6ed2a90b98 100644
--- a/tests/e2e/x/transfer/virtuous.go
+++ b/tests/e2e/x/transfer/virtuous.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 // Implements X-chain transfer tests.
 package transfer
 
diff --git a/tests/fixture/e2e/env.go b/tests/fixture/e2e/env.go
index 05fbbd97ac86..f56b9e9bce03 100644
--- a/tests/fixture/e2e/env.go
+++ b/tests/fixture/e2e/env.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package e2e
 
 import (
diff --git a/tests/fixture/e2e/helpers.go b/tests/fixture/e2e/helpers.go
index 6f6e5382dc7a..9bc773cbd6c1 100644
--- a/tests/fixture/e2e/helpers.go
+++ b/tests/fixture/e2e/helpers.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package e2e
 
 import (
diff --git a/vms/platformvm/warp/test_signer.go b/vms/platformvm/warp/test_signer.go
index e30423edf1ed..3cd3802af3f9 100644
--- a/vms/platformvm/warp/test_signer.go
+++ b/vms/platformvm/warp/test_signer.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package warp
 
 import (
diff --git a/wallet/subnet/primary/common/test_utxos.go b/wallet/subnet/primary/common/test_utxos.go
index 094c57d53705..0ab6b6decb8f 100644
--- a/wallet/subnet/primary/common/test_utxos.go
+++ b/wallet/subnet/primary/common/test_utxos.go
@@ -1,6 +1,8 @@
 // Copyright (C) 2019-2024, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+//go:build test
+
 package common
 
 import (