ci: Add ineffsign linter

And fix an additional ineffective assignment that was not caught by staticcheck

.golangci.yml

@@ -5,6 +5,7 @@ linters:
     - govet
     - unconvert
     - staticcheck
+    - ineffassign
 
 issues:
   # Disable the default exclude list so that all excludes are explicitly

agent/agent.go

@@ -706,8 +706,6 @@ func (a *Agent) setupClientAutoEncryptWatching(rootsReq *structs.DCSpecificReque
 	// in time. The agent would be stuck in that case because the watches
 	// never use the AutoEncrypt.Sign endpoint.
 	go func() {
-		for {
-
 		// Check 10sec after cert expires. The agent cache
 		// should be handling the expiration and renew before
 		// it.
@@ -716,8 +714,9 @@ func (a *Agent) setupClientAutoEncryptWatching(rootsReq *structs.DCSpecificReque
 		// renew, but this case shouldn't happen because at
 		// this point, auto_encrypt was just being setup
 		// successfully.
-			autoLogger := a.logger.Named(logging.AutoEncrypt)
 		interval := a.tlsConfigurator.AutoEncryptCertNotAfter().Sub(time.Now().Add(10 * time.Second))
+		autoLogger := a.logger.Named(logging.AutoEncrypt)
+		for {
 			a.logger.Debug("setting up client certificate expiration check on interval", "interval", interval)
 			select {
 			case <-a.shutdownCh:

agent/consul/acl_endpoint_test.go

@@ -4400,6 +4400,7 @@ func TestACLEndpoint_Login(t *testing.T) {
 		structs.BindingRuleBindTypeNode,
 		"${serviceaccount.name}",
 	)
+	require.NoError(t, err)
 
 	t.Run("do not provide a token", func(t *testing.T) {
 		req := structs.ACLLoginRequest{

lib/decode/decode_test.go

@@ -282,6 +282,9 @@ func decodeHCLToMapStructure(source string, target interface{}) error {
 		Metadata:   md,
 		Result:     target,
 	})
+	if err != nil {
+		return err
+	}
 	return decoder.Decode(&raw)
 }
 
@@ -305,6 +308,7 @@ func TestHookWeakDecodeFromSlice_DoesNotModifySliceTargetsFromSliceInterface(t *
 	})
 	require.NoError(t, err)
 	err = decoder.Decode(&raw)
+	require.NoError(t, err)
 
 	expected := &nested{
 		Slice: []Item{{Name: "first"}},