fix additional lint issues and expand linter scope (#344)

* use grpc.WithContextDialer instead of deprecated grpc.WithDialer

`time.Duration`s were being expected by the WithDialer callback.
However, the callback functions were not making use of this parameter
and hence their removal is safe.

* fix additional lint issues and expand linter scope

Author: Abhijeet

.github/workflows/test.yaml

@@ -33,8 +33,6 @@ jobs:
         fi
     - name: Lint code
       uses: golangci/golangci-lint-action@4afd733a84b1f43292c63897423277bb7f4313a9 # v8.0.0
-      with:
-        args: --enable-only errcheck # this is temporary until the other lint errors are fixed
   go-test:
     needs: go-fmt-and-vet
     runs-on: ubuntu-latest

client.go

@@ -14,7 +14,6 @@ import (
 	"fmt"
 	"hash"
 	"io"
-	"io/ioutil"
 	"net"
 	"os"
 	"os/exec"
@@ -202,7 +201,7 @@ type ClientConfig struct {
 	// SyncStdout, SyncStderr can be set to override the
 	// respective os.Std* values in the plugin. Care should be taken to
 	// avoid races here. If these are nil, then this will be set to
-	// ioutil.Discard.
+	// io.Discard.
 	SyncStdout io.Writer
 	SyncStderr io.Writer
 
@@ -401,7 +400,7 @@ func NewClient(config *ClientConfig) (c *Client) {
 	}
 
 	if config.Stderr == nil {
-		config.Stderr = ioutil.Discard
+		config.Stderr = io.Discard
 	}
 
 	if config.SyncStdout == nil {
@@ -853,15 +852,15 @@ func (c *Client) Start() (addr net.Addr, err error) {
 			var coreProtocol int
 			coreProtocol, err = strconv.Atoi(parts[0])
 			if err != nil {
-				err = fmt.Errorf("Error parsing core protocol version: %s", err)
+				err = fmt.Errorf("error parsing core protocol version: %s", err)
 				return
 			}
 
 			if coreProtocol != CoreProtocolVersion {
-				err = fmt.Errorf("Incompatible core API version with plugin. "+
+				err = fmt.Errorf("incompatible core API version with plugin. "+
 					"Plugin version: %s, Core version: %d\n\n"+
 					"To fix this, the plugin usually only needs to be recompiled.\n"+
-					"Please report this to the plugin author.", parts[0], CoreProtocolVersion)
+					"Please report this to the plugin author", parts[0], CoreProtocolVersion)
 				return
 			}
 		}
@@ -887,10 +886,16 @@ func (c *Client) Start() (addr net.Addr, err error) {
 		switch network {
 		case "tcp":
 			addr, err = net.ResolveTCPAddr("tcp", address)
+			if err != nil {
+				return nil, err
+			}
 		case "unix":
 			addr, err = net.ResolveUnixAddr("unix", address)
+			if err != nil {
+				return nil, err
+			}
 		default:
-			err = fmt.Errorf("Unknown address type: %s", address)
+			return nil, fmt.Errorf("unknown address type: %s", address)
 		}
 
 		// If we have a server type, then record that. We default to net/rpc
@@ -908,7 +913,7 @@ func (c *Client) Start() (addr net.Addr, err error) {
 			}
 		}
 		if !found {
-			err = fmt.Errorf("Unsupported plugin protocol %q. Supported: %v",
+			err = fmt.Errorf("unsupported plugin protocol %q. Supported: %v",
 				c.protocol, c.config.AllowedProtocols)
 			return addr, err
 		}
@@ -1041,7 +1046,7 @@ func (c *Client) checkProtoVersion(protoVersion string) (int, PluginSet, error)
 		return version, plugins, nil
 	}
 
-	return 0, nil, fmt.Errorf("Incompatible API version with plugin. "+
+	return 0, nil, fmt.Errorf("incompatible API version with plugin. "+
 		"Plugin version: %d, Client versions: %d", serverVersion, clientVersions)
 }
 
@@ -1097,8 +1102,8 @@ func (c *Client) Protocol() Protocol {
 	return c.protocol
 }
 
-func netAddrDialer(addr net.Addr) func(string, time.Duration) (net.Conn, error) {
-	return func(_ string, _ time.Duration) (net.Conn, error) {
+func netAddrDialer(addr net.Addr) func(context.Context, string) (net.Conn, error) {
+	return func(context.Context, string) (net.Conn, error) {
 		// Connect to the client
 		conn, err := net.Dial(addr.Network(), addr.String())
 		if err != nil {
@@ -1115,7 +1120,7 @@ func netAddrDialer(addr net.Addr) func(string, time.Duration) (net.Conn, error)
 
 // dialer is compatible with grpc.WithDialer and creates the connection
 // to the plugin.
-func (c *Client) dialer(_ string, timeout time.Duration) (net.Conn, error) {
+func (c *Client) dialer(ctx context.Context, _ string) (net.Conn, error) {
 	muxer, err := c.getGRPCMuxer(c.address)
 	if err != nil {
 		return nil, err
@@ -1128,7 +1133,7 @@ func (c *Client) dialer(_ string, timeout time.Duration) (net.Conn, error) {
 			return nil, err
 		}
 	} else {
-		conn, err = netAddrDialer(c.address)("", timeout)
+		conn, err = netAddrDialer(c.address)(ctx, "")
 		if err != nil {
 			return nil, err
 		}

client_posix_test.go

@@ -39,6 +39,7 @@ func TestClient_testInterfaceReattach(t *testing.T) {
 	if reattach == nil {
 		c.Kill()
 		t.Fatal("reattach config should be non-nil")
+		return // Required for staticcheck SA5011
 	}
 
 	// Find the process and defer a kill so we know it is gone

client_test.go

@@ -668,7 +668,7 @@ func testClient_reattachGRPC(t *testing.T, useReattachFunc bool) {
 
 func TestClient_reattachNotFound(t *testing.T) {
 	// Find a bad pid
-	var pid int = 5000
+	pid := 5000
 	for i := pid; i < 32000; i++ {
 		if _, err := os.FindProcess(i); err != nil {
 			pid = i
@@ -916,11 +916,7 @@ func TestClient_Stdin(t *testing.T) {
 		t.Fatalf("error: %s", err)
 	}
 
-	for {
-		if c.Exited() {
-			break
-		}
-
+	for !c.Exited() {
 		time.Sleep(50 * time.Millisecond)
 	}
 
@@ -954,10 +950,7 @@ func TestClient_SkipHostEnv(t *testing.T) {
 				t.Fatalf("error: %s", err)
 			}
 
-			for {
-				if c.Exited() {
-					break
-				}
+			for !c.Exited() {
 
 				time.Sleep(50 * time.Millisecond)
 			}
@@ -1072,7 +1065,7 @@ func TestClient_TLS(t *testing.T) {
 	}
 
 	// Grab the impl
-	raw, err := clientBad.Dispense("test")
+	_, err = clientBad.Dispense("test")
 	if err == nil {
 		t.Fatal("expected error, got nil")
 	}
@@ -1101,7 +1094,7 @@ func TestClient_TLS(t *testing.T) {
 	}
 
 	// Grab the impl
-	raw, err = client.Dispense("test")
+	raw, err := client.Dispense("test")
 	if err != nil {
 		t.Fatalf("err should be nil, got %s", err)
 	}

client_unix_test.go

@@ -12,7 +12,6 @@ import (
 	"os/exec"
 	"os/user"
 	"path/filepath"
-	"runtime"
 	"syscall"
 	"testing"
 
@@ -22,10 +21,6 @@ import (
 )
 
 func TestSetGroup(t *testing.T) {
-	if runtime.GOOS == "windows" {
-		t.Skip("go-plugin doesn't support unix sockets on Windows")
-	}
-
 	group, err := user.LookupGroupId(fmt.Sprintf("%d", os.Getgid()))
 	if err != nil {
 		t.Fatal(err)

examples/bidirectional/main.go

@@ -5,7 +5,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"os"
 	"os/exec"
@@ -23,7 +23,7 @@ func (*addHelper) Sum(a, b int64) (int64, error) {
 
 func main() {
 	// We don't want to see the plugin logs.
-	log.SetOutput(ioutil.Discard)
+	log.SetOutput(io.Discard)
 
 	// We're a host. Start by launching the plugin process.
 	client := plugin.NewClient(&plugin.ClientConfig{

examples/bidirectional/plugin-go-grpc/main.go

@@ -5,7 +5,7 @@ package main
 
 import (
 	"encoding/json"
-	"io/ioutil"
+	"os"
 
 	"github.com/hashicorp/go-plugin"
 	"github.com/hashicorp/go-plugin/examples/bidirectional/shared"
@@ -33,11 +33,11 @@ func (k *Counter) Put(key string, value int64, a shared.AddHelper) error {
 		return err
 	}
 
-	return ioutil.WriteFile("kv_"+key, buf, 0644)
+	return os.WriteFile("kv_"+key, buf, 0644)
 }
 
 func (k *Counter) Get(key string) (int64, error) {
-	dataRaw, err := ioutil.ReadFile("kv_" + key)
+	dataRaw, err := os.ReadFile("kv_" + key)
 	if err != nil {
 		return 0, err
 	}

examples/grpc/main.go

@@ -5,7 +5,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"os"
 	"os/exec"
@@ -57,15 +57,15 @@ func run() error {
 		}
 
 	default:
-		return fmt.Errorf("Please only use 'get' or 'put', given: %q", os.Args[0])
+		return fmt.Errorf("please only use 'get' or 'put', given: %q", os.Args[0])
 	}
 
 	return nil
 }
 
 func main() {
 	// We don't want to see the plugin logs.
-	log.SetOutput(ioutil.Discard)
+	log.SetOutput(io.Discard)
 
 	if err := run(); err != nil {
 		fmt.Printf("error: %+v\n", err)

examples/grpc/plugin-go-grpc/main.go

@@ -5,7 +5,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 
 	"github.com/hashicorp/go-plugin"
 	"github.com/hashicorp/go-plugin/examples/grpc/shared"
@@ -17,11 +17,11 @@ type KV struct{}
 
 func (KV) Put(key string, value []byte) error {
 	value = []byte(fmt.Sprintf("%s\n\nWritten from plugin-go-grpc", string(value)))
-	return ioutil.WriteFile("kv_"+key, value, 0644)
+	return os.WriteFile("kv_"+key, value, 0644)
 }
 
 func (KV) Get(key string) ([]byte, error) {
-	return ioutil.ReadFile("kv_" + key)
+	return os.ReadFile("kv_" + key)
 }
 
 func main() {

examples/grpc/plugin-go-netrpc/main.go

@@ -5,7 +5,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 
 	"github.com/hashicorp/go-plugin"
 	"github.com/hashicorp/go-plugin/examples/grpc/shared"
@@ -17,11 +17,11 @@ type KV struct{}
 
 func (KV) Put(key string, value []byte) error {
 	value = []byte(fmt.Sprintf("%s\n\nWritten from plugin-go-netrpc", string(value)))
-	return ioutil.WriteFile("kv_"+key, value, 0644)
+	return os.WriteFile("kv_"+key, value, 0644)
 }
 
 func (KV) Get(key string) ([]byte, error) {
-	return ioutil.ReadFile("kv_" + key)
+	return os.ReadFile("kv_" + key)
 }
 
 func main() {