Fix various golangci-lint errors (#2059)

pkg/tmpl/context_funcs.go

@@ -56,7 +56,7 @@ func (c *Context) Exec(command string, args []interface{}, inputs ...string) (st
 	for i, a := range args {
 		switch a.(type) {
 		case string:
-			strArgs[i] = a.(string)
+			strArgs[i] = fmt.Sprintf("%v", a)
 		default:
 			return "", fmt.Errorf("unexpected type of arg \"%s\" in args %v at index %d", reflect.TypeOf(a), args, i)
 		}

pkg/tmpl/context_funcs_test.go

@@ -3,10 +3,11 @@ package tmpl
 import (
 	"encoding/json"
 	"fmt"
-	"github.com/google/go-cmp/cmp"
 	"path/filepath"
 	"reflect"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 func TestReadFile(t *testing.T) {
@@ -207,14 +208,15 @@ func TestRequired(t *testing.T) {
 		},
 	}
 	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got, err := Required(tt.args.warn, tt.args.val)
-			if (err != nil) != tt.wantErr {
-				t.Errorf("Required() error = %v, wantErr %v", err, tt.wantErr)
+		testCase := tt
+		t.Run(testCase.name, func(t *testing.T) {
+			got, err := Required(testCase.args.warn, testCase.args.val)
+			if (err != nil) != testCase.wantErr {
+				t.Errorf("Required() error = %v, wantErr %v", err, testCase.wantErr)
 				return
 			}
-			if !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("Required() got = %v, want %v", got, tt.want)
+			if !reflect.DeepEqual(got, testCase.want) {
+				t.Errorf("Required() got = %v, want %v", got, testCase.want)
 			}
 		})
 	}

pkg/tmpl/expand_secret_ref.go

@@ -1,11 +1,11 @@
 package tmpl
 
 import (
-	"errors"
 	"fmt"
+	"sync"
+
 	"github.com/roboll/helmfile/pkg/plugins"
 	"github.com/variantdev/vals"
-	"sync"
 )
 
 //to generate mock run mockgen -source=expand_secret_ref.go -destination=expand_secrets_mock.go -package=tmpl
@@ -26,12 +26,12 @@ func fetchSecretValue(path string) (string, error) {
 
 	rendered, ok := resultMap["key"]
 	if !ok {
-		return "", errors.New(fmt.Sprintf("unexpected error occurred, %v doesn't have 'key' key", resultMap))
+		return "", fmt.Errorf("unexpected error occurred, %v doesn't have 'key' key", resultMap)
 	}
 
 	result, ok := rendered.(string)
 	if !ok {
-		return "", errors.New(fmt.Sprintf("expected %v to be string", rendered))
+		return "", fmt.Errorf("expected %v to be string", rendered)
 	}
 
 	return result, nil