Use nil for interface compliance (#2139)

Co-authored-by: Joshua Kim <20001595+joshua-kim@users.noreply.github.com>

api/admin/client.go

@@ -13,7 +13,7 @@ import (
 	"github.com/ava-labs/avalanchego/utils/rpc"
 )
 
-var _ Client = &client{}
+var _ Client = (*client)(nil)
 
 // Client interface for the Avalanche Platform Info API Endpoint
 type Client interface {

api/auth/auth.go

@@ -53,7 +53,7 @@ var (
 	errNoEndpoints                 = errors.New("must name at least one endpoint")
 	errTooManyEndpoints            = fmt.Errorf("can only name at most %d endpoints", maxEndpoints)
 
-	_ Auth = &auth{}
+	_ Auth = (*auth)(nil)
 )
 
 type Auth interface {

api/health/client.go

@@ -10,7 +10,7 @@ import (
 	"github.com/ava-labs/avalanchego/utils/rpc"
 )
 
-var _ Client = &client{}
+var _ Client = (*client)(nil)
 
 // Client interface for Avalanche Health API Endpoint
 type Client interface {

api/health/health.go

@@ -13,7 +13,7 @@ import (
 	"github.com/ava-labs/avalanchego/utils/logging"
 )
 
-var _ Health = &health{}
+var _ Health = (*health)(nil)
 
 // Health defines the full health service interface for registering, reporting
 // and refreshing health checks.

api/info/client.go

@@ -11,7 +11,7 @@ import (
 	"github.com/ava-labs/avalanchego/vms/platformvm/signer"
 )
 
-var _ Client = &client{}
+var _ Client = (*client)(nil)
 
 // Client interface for an Info API Client
 type Client interface {

api/ipcs/client.go

@@ -11,7 +11,7 @@ import (
 	"github.com/ava-labs/avalanchego/utils/rpc"
 )
 
-var _ Client = &client{}
+var _ Client = (*client)(nil)
 
 // Client interface for interacting with the IPCS endpoint
 type Client interface {

api/keystore/blockchain_keystore.go

@@ -12,7 +12,7 @@ import (
 	"github.com/ava-labs/avalanchego/utils/logging"
 )
 
-var _ BlockchainKeystore = &blockchainKeystore{}
+var _ BlockchainKeystore = (*blockchainKeystore)(nil)
 
 type BlockchainKeystore interface {
 	// Get a database that is able to read and write unencrypted values from the

api/keystore/client.go

@@ -11,7 +11,7 @@ import (
 	"github.com/ava-labs/avalanchego/utils/rpc"
 )
 
-var _ Client = &client{}
+var _ Client = (*client)(nil)
 
 // Client interface for Avalanche Keystore API Endpoint
 type Client interface {

api/keystore/gkeystore/keystore_client.go

@@ -16,7 +16,7 @@ import (
 	rpcdbpb "github.com/ava-labs/avalanchego/proto/pb/rpcdb"
 )
 
-var _ keystore.BlockchainKeystore = &Client{}
+var _ keystore.BlockchainKeystore = (*Client)(nil)
 
 // Client is a snow.Keystore that talks over RPC.
 type Client struct {

api/keystore/gkeystore/keystore_server.go

@@ -17,7 +17,7 @@ import (
 	rpcdbpb "github.com/ava-labs/avalanchego/proto/pb/rpcdb"
 )
 
-var _ keystorepb.KeystoreServer = &Server{}
+var _ keystorepb.KeystoreServer = (*Server)(nil)
 
 // Server is a snow.Keystore that is managed over RPC.
 type Server struct {

api/keystore/keystore.go

@@ -34,7 +34,7 @@ var (
 	usersPrefix = []byte("users")
 	bcsPrefix   = []byte("bcs")
 
-	_ Keystore = &keystore{}
+	_ Keystore = (*keystore)(nil)
 )
 
 type Keystore interface {

api/metrics/multi_gatherer.go

@@ -17,7 +17,7 @@ import (
 var (
 	errDuplicatedPrefix = errors.New("duplicated prefix")
 
-	_ MultiGatherer = &multiGatherer{}
+	_ MultiGatherer = (*multiGatherer)(nil)
 )
 
 // MultiGatherer extends the Gatherer interface by allowing additional gatherers

api/metrics/optional_gatherer.go

@@ -15,7 +15,7 @@ import (
 var (
 	errDuplicatedRegister = errors.New("duplicated register")
 
-	_ OptionalGatherer = &optionalGatherer{}
+	_ OptionalGatherer = (*optionalGatherer)(nil)
 )
 
 // OptionalGatherer extends the Gatherer interface by allowing the optional

api/server/server.go

@@ -38,7 +38,7 @@ var (
 	errUnknownLockOption = errors.New("invalid lock options")
 
 	_ PathAdder = readPathAdder{}
-	_ Server    = &server{}
+	_ Server    = (*server)(nil)
 )
 
 type PathAdder interface {

app/plugin/plugin.go

@@ -29,8 +29,8 @@ var (
 		Name: &appPlugin{},
 	}
 
-	_ plugin.Plugin     = &appPlugin{}
-	_ plugin.GRPCPlugin = &appPlugin{}
+	_ plugin.Plugin     = (*appPlugin)(nil)
+	_ plugin.GRPCPlugin = (*appPlugin)(nil)
 )
 
 type appPlugin struct {

app/process/process.go

@@ -31,7 +31,7 @@ var (
 	stakingPortName = fmt.Sprintf("%s-staking", constants.AppName)
 	httpPortName    = fmt.Sprintf("%s-http", constants.AppName)
 
-	_ app.App = &process{}
+	_ app.App = (*process)(nil)
 )
 
 // process is a wrapper around a node that runs in this process

cache/lru_cache.go

@@ -10,7 +10,7 @@ import (
 
 const minCacheSize = 32
 
-var _ Cacher = &LRU{}
+var _ Cacher = (*LRU)(nil)
 
 type entry struct {
 	Key   interface{}

cache/metercacher/cache.go

@@ -10,7 +10,7 @@ import (
 	"github.com/ava-labs/avalanchego/utils/timer/mockable"
 )
 
-var _ cache.Cacher = &Cache{}
+var _ cache.Cacher = (*Cache)(nil)
 
 type Cache struct {
 	metrics

cache/unique_cache.go

@@ -8,7 +8,7 @@ import (
 	"sync"
 )
 
-var _ Deduplicator = &EvictableLRU{}
+var _ Deduplicator = (*EvictableLRU)(nil)
 
 // EvictableLRU is an LRU cache that notifies the objects when they are evicted.
 type EvictableLRU struct {

chains/atomic/gsharedmemory/shared_memory_client.go

@@ -24,7 +24,7 @@ const (
 	baseElementSize = 8 // bytes
 )
 
-var _ atomic.SharedMemory = &Client{}
+var _ atomic.SharedMemory = (*Client)(nil)
 
 // Client is atomic.SharedMemory that talks over RPC.
 type Client struct {

chains/atomic/gsharedmemory/shared_memory_server.go

@@ -14,7 +14,7 @@ import (
 	sharedmemorypb "github.com/ava-labs/avalanchego/proto/pb/sharedmemory"
 )
 
-var _ sharedmemorypb.SharedMemoryServer = &Server{}
+var _ sharedmemorypb.SharedMemoryServer = (*Server)(nil)
 
 // Server is shared memory that is managed over RPC.
 type Server struct {

chains/atomic/shared_memory.go

@@ -9,7 +9,7 @@ import (
 	"github.com/ava-labs/avalanchego/ids"
 )
 
-var _ SharedMemory = &sharedMemory{}
+var _ SharedMemory = (*sharedMemory)(nil)
 
 type Requests struct {
 	RemoveRequests [][]byte   `serialize:"true"`

chains/manager.go

@@ -72,7 +72,7 @@ var (
 	errCreatePlatformVM = errors.New("attempted to create a chain running the PlatformVM")
 	errNotBootstrapped  = errors.New("chains not bootstrapped")
 
-	_ Manager = &manager{}
+	_ Manager = (*manager)(nil)
 )
 
 // Manager manages the chains running on this node.

chains/mock_manager.go

@@ -8,7 +8,7 @@ import (
 	"github.com/ava-labs/avalanchego/snow/networking/router"
 )
 
-var _ Manager = MockManager{}
+var _ Manager = (*MockManager)(nil)
 
 // MockManager implements Manager but does nothing. Always returns nil error.
 // To be used only in tests

chains/subnet.go

@@ -12,7 +12,7 @@ import (
 	"github.com/ava-labs/avalanchego/snow/networking/sender"
 )
 
-var _ Subnet = &subnet{}
+var _ Subnet = (*subnet)(nil)
 
 // Subnet keeps track of the currently bootstrapping chains in a subnet. If no
 // chains in the subnet are currently bootstrapping, the subnet is considered

codec/hierarchycodec/codec.go

@@ -19,10 +19,10 @@ const (
 )
 
 var (
-	_ Codec              = &hierarchyCodec{}
-	_ codec.Codec        = &hierarchyCodec{}
-	_ codec.Registry     = &hierarchyCodec{}
-	_ codec.GeneralCodec = &hierarchyCodec{}
+	_ Codec              = (*hierarchyCodec)(nil)
+	_ codec.Codec        = (*hierarchyCodec)(nil)
+	_ codec.Registry     = (*hierarchyCodec)(nil)
+	_ codec.GeneralCodec = (*hierarchyCodec)(nil)
 )
 
 // Codec marshals and unmarshals

codec/linearcodec/codec.go

@@ -19,10 +19,10 @@ const (
 )
 
 var (
-	_ Codec              = &linearCodec{}
-	_ codec.Codec        = &linearCodec{}
-	_ codec.Registry     = &linearCodec{}
-	_ codec.GeneralCodec = &linearCodec{}
+	_ Codec              = (*linearCodec)(nil)
+	_ codec.Codec        = (*linearCodec)(nil)
+	_ codec.Registry     = (*linearCodec)(nil)
+	_ codec.GeneralCodec = (*linearCodec)(nil)
 )
 
 // Codec marshals and unmarshals

codec/manager.go

@@ -31,7 +31,7 @@ var (
 	errDuplicatedVersion = errors.New("duplicated codec version")
 )
 
-var _ Manager = &manager{}
+var _ Manager = (*manager)(nil)
 
 // Manager describes the functionality for managing codec versions.
 type Manager interface {

codec/reflectcodec/struct_fielder.go

@@ -18,7 +18,7 @@ const (
 	TagValue = "true"
 )
 
-var _ StructFielder = &structFielder{}
+var _ StructFielder = (*structFielder)(nil)
 
 type FieldDesc struct {
 	Index       int

codec/reflectcodec/type_codec.go

@@ -27,7 +27,7 @@ var (
 	errExtraSpace   = errors.New("trailing buffer space")
 )
 
-var _ codec.Codec = &genericCodec{}
+var _ codec.Codec = (*genericCodec)(nil)
 
 type TypeCodec interface {
 	// UnpackPrefix unpacks the prefix of an interface from the given packer.

codec/test_codec.go

@@ -49,8 +49,8 @@ var MultipleTagsTests = []func(c GeneralCodec, t testing.TB){
 // for the sake of testing
 
 var (
-	_ Foo = &MyInnerStruct{}
-	_ Foo = &MyInnerStruct2{}
+	_ Foo = (*MyInnerStruct)(nil)
+	_ Foo = (*MyInnerStruct2)(nil)
 )
 
 type Foo interface {

database/corruptabledb/db.go

@@ -11,8 +11,8 @@ import (
 )
 
 var (
-	_ database.Database = &Database{}
-	_ database.Batch    = &batch{}
+	_ database.Database = (*Database)(nil)
+	_ database.Batch    = (*batch)(nil)
 )
 
 // CorruptableDB is a wrapper around Database

database/encdb/db.go

@@ -23,9 +23,9 @@ const (
 )
 
 var (
-	_ database.Database = &Database{}
-	_ database.Batch    = &batch{}
-	_ database.Iterator = &iterator{}
+	_ database.Database = (*Database)(nil)
+	_ database.Batch    = (*batch)(nil)
+	_ database.Iterator = (*iterator)(nil)
 )
 
 // Database encrypts all values that are provided

database/leveldb/db.go

@@ -63,9 +63,9 @@ const (
 )
 
 var (
-	_ database.Database = &Database{}
-	_ database.Batch    = &batch{}
-	_ database.Iterator = &iter{}
+	_ database.Database = (*Database)(nil)
+	_ database.Batch    = (*batch)(nil)
+	_ database.Iterator = (*iter)(nil)
 )
 
 // Database is a persistent key-value store. Apart from basic data storage

database/linkeddb/linkeddb.go

@@ -18,8 +18,8 @@ const (
 var (
 	headKey = []byte{0x01}
 
-	_ LinkedDB          = &linkedDB{}
-	_ database.Iterator = &iterator{}
+	_ LinkedDB          = (*linkedDB)(nil)
+	_ database.Iterator = (*iterator)(nil)
 )
 
 // LinkedDB provides a key value interface while allowing iteration.

database/manager/manager.go

@@ -29,7 +29,7 @@ var (
 	errNoDBs                 = errors.New("no dbs given")
 )
 
-var _ Manager = &manager{}
+var _ Manager = (*manager)(nil)
 
 type Manager interface {
 	// Current returns the database with the current database version.

database/memdb/db.go

@@ -22,9 +22,9 @@ const (
 )
 
 var (
-	_ database.Database = &Database{}
-	_ database.Batch    = &batch{}
-	_ database.Iterator = &iterator{}
+	_ database.Database = (*Database)(nil)
+	_ database.Batch    = (*batch)(nil)
+	_ database.Iterator = (*iterator)(nil)
 )
 
 // Database is an ephemeral key-value store that implements the Database

database/meterdb/db.go

@@ -11,9 +11,9 @@ import (
 )
 
 var (
-	_ database.Database = &Database{}
-	_ database.Batch    = &batch{}
-	_ database.Iterator = &iterator{}
+	_ database.Database = (*Database)(nil)
+	_ database.Batch    = (*batch)(nil)
+	_ database.Iterator = (*iterator)(nil)
 )
 
 // Database tracks the amount of time each operation takes and how many bytes

database/mockdb/db.go

@@ -12,7 +12,7 @@ import (
 var (
 	errNoFunction = errors.New("user didn't specify what value(s) return")
 
-	_ database.Database = &Database{}
+	_ database.Database = (*Database)(nil)
 )
 
 // Database is a mock database meant to be used in tests.

database/nodb/db.go

@@ -8,9 +8,9 @@ import (
 )
 
 var (
-	_ database.Database = &Database{}
-	_ database.Batch    = &Batch{}
-	_ database.Iterator = &Iterator{}
+	_ database.Database = (*Database)(nil)
+	_ database.Batch    = (*Batch)(nil)
+	_ database.Iterator = (*Iterator)(nil)
 )
 
 // Database is a lightning fast key value store with probabilistic operations.