[ci] add nonamedreturns linter

.golangci.yaml

@@ -8,7 +8,7 @@ linters:
     - depguard
     - dogsled
     - durationcheck
-    - exportloopref
+    - copyloopvar
     - gci
     - gochecknoinits
     - gocritic
@@ -20,6 +20,7 @@ linters:
     - ineffassign
     - misspell
     - nolintlint
+    - nonamedreturns
     - prealloc
     - revive
     - sloglint
@@ -78,6 +79,10 @@ linters-settings:
         deny:
           - pkg: "gopkg.in/satori/go.uuid.v1"
             desc: "Use https://github.com/gofrs/uuid instead. Satori/go.uuid is no longer maintained and has critical vulnerabilities."
+  nonamedreturns:
+    # Report named error if it is assigned inside defer.
+    # Default: false
+    report-error-in-defer: false
 issues:
   exclude-dirs:
     - test/integration

pkg/debug/server.go

@@ -43,33 +43,28 @@ func NewServer(prefix, socketPath, httpAddr string, logger *log.Logger) *Server
 	}
 }
 
-func (s *Server) Init() (err error) {
+func (s *Server) Init() error {
 	address := s.SocketPath
 
-	err = os.MkdirAll(path.Dir(address), 0o700)
-	if err != nil {
-		s.logger.Errorf("Debug HTTP server fail to create socket '%s': %v", address, err)
-		return err
+	if err := os.MkdirAll(path.Dir(address), 0o700); err != nil {
+		return fmt.Errorf("Debug HTTP server fail to create socket '%s': %w", address, err)
 	}
 
 	exists, err := utils.FileExists(address)
 	if err != nil {
-		s.logger.Errorf("Debug HTTP server fail to check socket '%s': %v", address, err)
-		return err
+		return fmt.Errorf("Debug HTTP server fail to check socket '%s': %w", address, err)
 	}
+
 	if exists {
-		err = os.Remove(address)
-		if err != nil {
-			s.logger.Errorf("Debug HTTP server fail to remove existing socket '%s': %v", address, err)
-			return err
+		if err := os.Remove(address); err != nil {
+			return fmt.Errorf("Debug HTTP server fail to check socket '%s': %w", address, err)
 		}
 	}
 
 	// Check if socket is available
 	listener, err := net.Listen("unix", address)
 	if err != nil {
-		s.logger.Errorf("Debug HTTP server fail to listen on '%s': %v", address, err)
-		return err
+		return fmt.Errorf("Debug HTTP server fail to listen on '%s': %w", address, err)
 	}
 
 	s.logger.Infof("Debug endpoint listen on %s", address)
@@ -153,7 +148,9 @@ func handleFormattedOutput(writer http.ResponseWriter, request *http.Request, ha
 	}
 }
 
-func transformUsingFormat(w io.Writer, val interface{}, format string) (err error) {
+func transformUsingFormat(w io.Writer, val interface{}, format string) error {
+	var err error
+
 	switch format {
 	case "yaml":
 		enc := yaml.NewEncoder(w)

pkg/filter/jq/jq_exec.go

@@ -10,7 +10,7 @@ import (
 )
 
 // jqExec is a subprocess implementation of the jq filtering.
-func jqExec(jqFilter string, jsonData []byte, libPath string) (result string, err error) {
+func jqExec(jqFilter string, jsonData []byte, libPath string) (string, error) {
 	var cmd *exec.Cmd
 	if libPath == "" {
 		cmd = exec.Command("jq", jqFilter)
@@ -19,14 +19,16 @@ func jqExec(jqFilter string, jsonData []byte, libPath string) (result string, er
 	}
 
 	var stdinBuf bytes.Buffer
-	_, err = stdinBuf.WriteString(string(jsonData))
+	_, err := stdinBuf.WriteString(string(jsonData))
 	if err != nil {
 		panic(err)
 	}
-	cmd.Stdin = &stdinBuf
+
 	var stdoutBuf bytes.Buffer
-	cmd.Stdout = &stdoutBuf
 	var stderrBuf bytes.Buffer
+
+	cmd.Stdin = &stdinBuf
+	cmd.Stdout = &stdoutBuf
 	cmd.Stderr = &stderrBuf
 
 	err = executor.Run(cmd)

pkg/hook/config/config_v0.go

@@ -43,30 +43,31 @@ type KubeNamespaceSelectorV0 struct {
 }
 
 // ConvertAndCheckV0 fills non-versioned structures and run inter-field checks not covered by OpenAPI schemas.
-func (cv0 *HookConfigV0) ConvertAndCheck(c *HookConfig) (err error) {
-	c.OnStartup, err = c.ConvertOnStartup(cv0.OnStartup)
-	if err != nil {
+func (cv0 *HookConfigV0) ConvertAndCheck(c *HookConfig) error {
+	var err error
+
+	if c.OnStartup, err = c.ConvertOnStartup(cv0.OnStartup); err != nil {
 		return err
 	}
 
 	c.Schedules = []htypes.ScheduleConfig{}
 	for i, rawSchedule := range cv0.Schedule {
-		err := cv0.CheckSchedule(rawSchedule)
-		if err != nil {
-			return fmt.Errorf("invalid schedule config [%d]: %v", i, err)
+		if err := cv0.CheckSchedule(rawSchedule); err != nil {
+			return fmt.Errorf("invalid schedule config [%d]: %w", i, err)
 		}
+
 		schedule, err := cv0.ConvertSchedule(rawSchedule)
 		if err != nil {
 			return err
 		}
+
 		c.Schedules = append(c.Schedules, schedule)
 	}
 
 	c.OnKubernetesEvents = []htypes.OnKubernetesEventConfig{}
 	for i, kubeCfg := range cv0.OnKubernetesEvent {
-		err := cv0.CheckOnKubernetesEvent(kubeCfg, fmt.Sprintf("onKubernetesEvent[%d]", i))
-		if err != nil {
-			return fmt.Errorf("invalid onKubernetesEvent config [%d]: %v", i, err)
+		if err := cv0.CheckOnKubernetesEvent(kubeCfg, fmt.Sprintf("onKubernetesEvent[%d]", i)); err != nil {
+			return fmt.Errorf("invalid onKubernetesEvent config [%d]: %w", i, err)
 		}
 
 		monitor := &kubeeventsmanager.MonitorConfig{}