code health: fix all places highlighted by linter

Removed error's suppression in check.yaml.

Suppressed the highlighting of errorcheck in all methods,
having encodeXxx inside. For now these methods are not able to
return any error cause of internal implementation of writer
interface. For future, if the implementation of writer
will be changed, and we will have to check errors, we must think
about how to say to compiler that the error check is 'unlikely'.

Fixed the use of time package API, all places with calls of
time.Now().Sub(). Now time package propose the explicit time.Until().

Replaced some calls of Errorf() with Fatalf() in tests. That change
prevents nil dereferences below in the code.

Suppressed the highlighting of all unused constants and functions.

Fixed calling of Fatalf from non-testing goroutine in queue tests.
It is not a valid way to stop test from another goroutine.

Relates to #142

.github/workflows/check.yaml

@@ -39,4 +39,4 @@ jobs:
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v2
         with:
-          args: --issues-exit-code=0 -E gofmt
+          args: -E gofmt

client_tools.go

@@ -10,6 +10,7 @@ type IntKey struct {
 	I int
 }
 
+//nolint: errcheck
 func (k IntKey) EncodeMsgpack(enc *msgpack.Encoder) error {
 	enc.EncodeSliceLen(1)
 	enc.EncodeInt(k.I)
@@ -22,6 +23,7 @@ type UintKey struct {
 	I uint
 }
 
+//nolint: errcheck
 func (k UintKey) EncodeMsgpack(enc *msgpack.Encoder) error {
 	enc.EncodeSliceLen(1)
 	enc.EncodeUint(k.I)
@@ -34,6 +36,7 @@ type StringKey struct {
 	S string
 }
 
+//nolint: errcheck
 func (k StringKey) EncodeMsgpack(enc *msgpack.Encoder) error {
 	enc.EncodeSliceLen(1)
 	enc.EncodeString(k.S)
@@ -46,6 +49,7 @@ type IntIntKey struct {
 	I1, I2 int
 }
 
+//nolint: errcheck
 func (k IntIntKey) EncodeMsgpack(enc *msgpack.Encoder) error {
 	enc.EncodeSliceLen(2)
 	enc.EncodeInt(k.I1)
@@ -60,6 +64,7 @@ type Op struct {
 	Arg   interface{}
 }
 
+//nolint: errcheck
 func (o Op) EncodeMsgpack(enc *msgpack.Encoder) error {
 	enc.EncodeSliceLen(3)
 	enc.EncodeString(o.Op)
@@ -75,6 +80,7 @@ type OpSplice struct {
 	Replace string
 }
 
+//nolint: errcheck
 func (o OpSplice) EncodeMsgpack(enc *msgpack.Encoder) error {
 	enc.EncodeSliceLen(5)
 	enc.EncodeString(o.Op)

connection.go

@@ -147,7 +147,7 @@ type connShard struct {
 	bufmut sync.Mutex
 	buf    smallWBuf
 	enc    *msgpack.Encoder
-	_pad   [16]uint64
+	_pad   [16]uint64 //nolint: structcheck,unused
 }
 
 // Greeting is a message sent by Tarantool on connect.
@@ -228,6 +228,7 @@ type Opts struct {
 // - If opts.Reconnect is non-zero, then error will be returned only if authorization
 // fails. But if Tarantool is not reachable, then it will make an attempt to reconnect later
 // and will not finish to make attempts on authorization failures.
+//nolint: errcheck
 func Connect(addr string, opts Opts) (conn *Connection, err error) {
 	conn = &Connection{
 		addr:      addr,
@@ -495,7 +496,7 @@ func (conn *Connection) createConnection(reconnect bool) (err error) {
 		conn.notify(ReconnectFailed)
 		reconnects++
 		conn.mutex.Unlock()
-		time.Sleep(now.Add(conn.opts.Reconnect).Sub(time.Now()))
+		time.Sleep(time.Until(now.Add(conn.opts.Reconnect)))
 		conn.mutex.Lock()
 	}
 	if conn.state == connClosed {
@@ -538,6 +539,7 @@ func (conn *Connection) closeConnection(neterr error, forever bool) (err error)
 	return
 }
 
+//nolint: errcheck
 func (conn *Connection) reconnect(neterr error, c net.Conn) {
 	conn.mutex.Lock()
 	defer conn.mutex.Unlock()
@@ -567,6 +569,7 @@ func (conn *Connection) unlockShards() {
 	}
 }
 
+//nolint: errcheck
 func (conn *Connection) pinger() {
 	to := conn.opts.Timeout
 	if to == 0 {
@@ -688,7 +691,7 @@ func (conn *Connection) newFuture(requestCode int32) (fut *Future) {
 	*pair.last = fut
 	pair.last = &fut.next
 	if conn.opts.Timeout > 0 {
-		fut.timeout = time.Now().Sub(epoch) + conn.opts.Timeout
+		fut.timeout = time.Until(epoch) + conn.opts.Timeout
 	}
 	shard.rmut.Unlock()
 	if conn.rlimit != nil && conn.opts.RLimitAction == RLimitWait {
@@ -796,9 +799,9 @@ func (conn *Connection) timeouts() {
 			return
 		case <-t.C:
 		}
-		minNext := time.Now().Sub(epoch) + timeout
+		minNext := time.Until(epoch) + timeout
 		for i := range conn.shard {
-			nowepoch = time.Now().Sub(epoch)
+			nowepoch = time.Until(epoch)
 			shard := &conn.shard[i]
 			for pos := range shard.requests {
 				shard.rmut.Lock()
@@ -825,7 +828,7 @@ func (conn *Connection) timeouts() {
 				shard.rmut.Unlock()
 			}
 		}
-		nowepoch = time.Now().Sub(epoch)
+		nowepoch = time.Until(epoch)
 		if nowepoch+time.Microsecond < minNext {
 			t.Reset(minNext - nowepoch)
 		} else {

deadline_io.go

@@ -10,6 +10,7 @@ type DeadlineIO struct {
 	c  net.Conn
 }
 
+//nolint: errcheck
 func (d *DeadlineIO) Write(b []byte) (n int, err error) {
 	if d.to > 0 {
 		d.c.SetWriteDeadline(time.Now().Add(d.to))
@@ -18,6 +19,7 @@ func (d *DeadlineIO) Write(b []byte) (n int, err error) {
 	return
 }
 
+//nolint: errcheck
 func (d *DeadlineIO) Read(b []byte) (n int, err error) {
 	if d.to > 0 {
 		d.c.SetReadDeadline(time.Now().Add(d.to))

example_custom_unpacking_test.go

@@ -16,13 +16,14 @@ type Tuple2 struct {
 
 // Same effect in a "magic" way, but slower.
 type Tuple3 struct {
-	_msgpack struct{} `msgpack:",asArray"`
+	_msgpack struct{} `msgpack:",asArray"` //nolint: structcheck,unused
 
 	Cid     uint
 	Orig    string
 	Members []Member
 }
 
+//nolint: errcheck
 func (c *Tuple2) EncodeMsgpack(e *msgpack.Encoder) error {
 	if err := e.EncodeSliceLen(3); err != nil {
 		return err
@@ -37,6 +38,7 @@ func (c *Tuple2) EncodeMsgpack(e *msgpack.Encoder) error {
 	return nil
 }
 
+//nolint: errcheck
 func (c *Tuple2) DecodeMsgpack(d *msgpack.Decoder) error {
 	var err error
 	var l int

example_test.go

@@ -10,7 +10,7 @@ import (
 type Tuple struct {
 	// Instruct msgpack to pack this struct as array, so no custom packer
 	// is needed.
-	_msgpack struct{} `msgpack:",asArray"`
+	_msgpack struct{} `msgpack:",asArray"` //nolint: structcheck,unused
 	Id       uint
 	Msg      string
 	Name     string
@@ -24,6 +24,7 @@ func example_connect() *tarantool.Connection {
 	return conn
 }
 
+//nolint: errcheck
 func ExampleConnection_Select() {
 	conn := example_connect()
 	defer conn.Close()
@@ -70,6 +71,7 @@ func ExampleConnection_SelectTyped() {
 	// response is [{{} 1111 hello world}]
 }
 
+//nolint
 func ExampleConnection_SelectAsync() {
 	conn := example_connect()
 	defer conn.Close()
@@ -118,6 +120,7 @@ func ExampleConnection_Ping() {
 	// Ping Error <nil>
 }
 
+//nolint: errcheck
 func ExampleConnection_Insert() {
 	conn := example_connect()
 	defer conn.Close()
@@ -151,6 +154,7 @@ func ExampleConnection_Insert() {
 
 }
 
+//nolint: errcheck
 func ExampleConnection_Delete() {
 	conn := example_connect()
 	defer conn.Close()
@@ -184,6 +188,7 @@ func ExampleConnection_Delete() {
 	// Data [[36 test one]]
 }
 
+//nolint: errcheck
 func ExampleConnection_Replace() {
 	conn := example_connect()
 	defer conn.Close()
@@ -233,6 +238,7 @@ func ExampleConnection_Replace() {
 	// Data [[13 test twelve]]
 }
 
+//nolint: errcheck
 func ExampleConnection_Update() {
 	conn := example_connect()
 	defer conn.Close()

queue/example_msgpack_test.go

@@ -46,6 +46,7 @@ func (c *dummyData) EncodeMsgpack(e *msgpack.Encoder) error {
 // - If you use the connection timeout and call Take, we return an error if we
 // cannot take the task out of the queue within the time corresponding to the
 // connection timeout.
+//nolint: errcheck,ineffassign
 func Example_simpleQueueCustomMsgPack() {
 	opts := tarantool.Opts{
 		Reconnect:     time.Second,

queue/example_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/tarantool/go-tarantool/queue"
 )
 
+//nolint
 // Example demonstrates an operations like Put and Take with queue.
 func Example_simpleQueue() {
 	cfg := queue.Cfg{

queue/queue.go

@@ -339,6 +339,7 @@ type queueData struct {
 	result interface{}
 }
 
+//nolint
 func (qd *queueData) DecodeMsgpack(d *msgpack.Decoder) error {
 	var err error
 	var l int

queue/queue_test.go

@@ -794,16 +794,22 @@ func TestUtube_Put(t *testing.T) {
 		t.Fatalf("Failed put task to queue: %s", err.Error())
 	}
 
+	errChan := make(chan struct{})
 	go func() {
 		t1, err := q.TakeTimeout(2 * time.Second)
 		if err != nil {
-			t.Fatalf("Failed to take task from utube: %s", err.Error())
+			t.Errorf("Failed to take task from utube: %s", err.Error())
+			errChan <- struct{}{}
+			return
 		}
 
 		time.Sleep(2 * time.Second)
 		if err := t1.Ack(); err != nil {
-			t.Fatalf("Failed to ack task: %s", err.Error())
+			t.Errorf("Failed to ack task: %s", err.Error())
+			errChan <- struct{}{}
+			return
 		}
+		close(errChan)
 	}()
 
 	time.Sleep(100 * time.Millisecond)
@@ -817,6 +823,9 @@ func TestUtube_Put(t *testing.T) {
 		t.Fatalf("Failed to ack task: %s", err.Error())
 	}
 	end := time.Now()
+	if _, ok := <-errChan; ok {
+		t.Fatalf("One of take failed")
+	}
 	if math.Abs(float64(end.Sub(start)-2*time.Second)) > float64(200*time.Millisecond) {
 		t.Fatalf("Blocking time is less than expected: actual = %.2fs, expected = 1s", end.Sub(start).Seconds())
 	}

request.go

@@ -19,11 +19,13 @@ type Future struct {
 }
 
 // Ping sends empty request to Tarantool to check connection.
+//nolint: errcheck
 func (conn *Connection) Ping() (resp *Response, err error) {
 	future := conn.newFuture(PingRequest)
 	return future.send(conn, func(enc *msgpack.Encoder) error { enc.EncodeMapLen(0); return nil }).Get()
 }
 
+//nolint: errcheck
 func (req *Future) fillSearch(enc *msgpack.Encoder, spaceNo, indexNo uint32, key interface{}) error {
 	enc.EncodeUint64(KeySpaceNo)
 	enc.EncodeUint64(uint64(spaceNo))
@@ -33,6 +35,7 @@ func (req *Future) fillSearch(enc *msgpack.Encoder, spaceNo, indexNo uint32, key
 	return enc.Encode(key)
 }
 
+//nolint: errcheck
 func (req *Future) fillIterator(enc *msgpack.Encoder, offset, limit, iterator uint32) {
 	enc.EncodeUint64(KeyIterator)
 	enc.EncodeUint64(uint64(iterator))
@@ -42,6 +45,7 @@ func (req *Future) fillIterator(enc *msgpack.Encoder, offset, limit, iterator ui
 	enc.EncodeUint64(uint64(limit))
 }
 
+//nolint: errcheck
 func (req *Future) fillInsert(enc *msgpack.Encoder, spaceNo uint32, tuple interface{}) error {
 	enc.EncodeUint64(KeySpaceNo)
 	enc.EncodeUint64(uint64(spaceNo))
@@ -213,6 +217,7 @@ func (conn *Connection) EvalTyped(expr string, args interface{}, result interfac
 }
 
 // SelectAsync sends select request to Tarantool and returns Future.
+//nolint: errcheck
 func (conn *Connection) SelectAsync(space, index interface{}, offset, limit, iterator uint32, key interface{}) *Future {
 	future := conn.newFuture(SelectRequest)
 	spaceNo, indexNo, err := conn.Schema.resolveSpaceIndex(space, index)
@@ -228,6 +233,7 @@ func (conn *Connection) SelectAsync(space, index interface{}, offset, limit, ite
 
 // InsertAsync sends insert action to Tarantool and returns Future.
 // Tarantool will reject Insert when tuple with same primary key exists.
+//nolint: errcheck
 func (conn *Connection) InsertAsync(space interface{}, tuple interface{}) *Future {
 	future := conn.newFuture(InsertRequest)
 	spaceNo, _, err := conn.Schema.resolveSpaceIndex(space, nil)
@@ -242,6 +248,7 @@ func (conn *Connection) InsertAsync(space interface{}, tuple interface{}) *Futur
 
 // ReplaceAsync sends "insert or replace" action to Tarantool and returns Future.
 // If tuple with same primary key exists, it will be replaced.
+//nolint: errcheck
 func (conn *Connection) ReplaceAsync(space interface{}, tuple interface{}) *Future {
 	future := conn.newFuture(ReplaceRequest)
 	spaceNo, _, err := conn.Schema.resolveSpaceIndex(space, nil)
@@ -256,6 +263,7 @@ func (conn *Connection) ReplaceAsync(space interface{}, tuple interface{}) *Futu
 
 // DeleteAsync sends deletion action to Tarantool and returns Future.
 // Future's result will contain array with deleted tuple.
+//nolint: errcheck
 func (conn *Connection) DeleteAsync(space, index interface{}, key interface{}) *Future {
 	future := conn.newFuture(DeleteRequest)
 	spaceNo, indexNo, err := conn.Schema.resolveSpaceIndex(space, index)
@@ -270,6 +278,7 @@ func (conn *Connection) DeleteAsync(space, index interface{}, key interface{}) *
 
 // Update sends deletion of a tuple by key and returns Future.
 // Future's result will contain array with updated tuple.
+//nolint: errcheck
 func (conn *Connection) UpdateAsync(space, index interface{}, key, ops interface{}) *Future {
 	future := conn.newFuture(UpdateRequest)
 	spaceNo, indexNo, err := conn.Schema.resolveSpaceIndex(space, index)
@@ -288,6 +297,7 @@ func (conn *Connection) UpdateAsync(space, index interface{}, key, ops interface
 
 // UpsertAsync sends "update or insert" action to Tarantool and returns Future.
 // Future's sesult will not contain any tuple.
+//nolint: errcheck
 func (conn *Connection) UpsertAsync(space interface{}, tuple interface{}, ops interface{}) *Future {
 	future := conn.newFuture(UpsertRequest)
 	spaceNo, _, err := conn.Schema.resolveSpaceIndex(space, nil)
@@ -309,6 +319,7 @@ func (conn *Connection) UpsertAsync(space interface{}, tuple interface{}, ops in
 
 // CallAsync sends a call to registered Tarantool function and returns Future.
 // It uses request code for Tarantool 1.6, so future's result is always array of arrays
+//nolint: errcheck
 func (conn *Connection) CallAsync(functionName string, args interface{}) *Future {
 	future := conn.newFuture(CallRequest)
 	return future.send(conn, func(enc *msgpack.Encoder) error {
@@ -323,6 +334,7 @@ func (conn *Connection) CallAsync(functionName string, args interface{}) *Future
 // Call17Async sends a call to registered Tarantool function and returns Future.
 // It uses request code for Tarantool 1.7, so future's result will not be converted
 // (though, keep in mind, result is always array)
+//nolint: errcheck
 func (conn *Connection) Call17Async(functionName string, args interface{}) *Future {
 	future := conn.newFuture(Call17Request)
 	return future.send(conn, func(enc *msgpack.Encoder) error {
@@ -335,6 +347,7 @@ func (conn *Connection) Call17Async(functionName string, args interface{}) *Futu
 }
 
 // EvalAsync sends a Lua expression for evaluation and returns Future.
+//nolint: errcheck
 func (conn *Connection) EvalAsync(expr string, args interface{}) *Future {
 	future := conn.newFuture(EvalRequest)
 	return future.send(conn, func(enc *msgpack.Encoder) error {
@@ -350,6 +363,7 @@ func (conn *Connection) EvalAsync(expr string, args interface{}) *Future {
 // private
 //
 
+//nolint: errcheck
 func (fut *Future) pack(h *smallWBuf, enc *msgpack.Encoder, body func(*msgpack.Encoder) error) (err error) {
 	rid := fut.requestId
 	hl := h.Len()