simplify os.ReadFile, fine tune messages and comments, fix lint

modules/options/base.go

@@ -102,12 +102,12 @@ func readFileFromLocal(base []string, sub string, elems ...string) ([]byte, erro
 	for _, dir := range base {
 		localPathElems[0] = dir
 		localPath := util.SafeFilePathAbs(localPathElems...)
-		isFile, err := util.IsFile(localPath)
-		if err != nil {
-			log.Error("Unable to check if %s is a file. Error: %v", localPath, err)
-		} else if isFile {
-			return os.ReadFile(localPath)
+		data, err := os.ReadFile(localPath)
+		if err == nil {
+			return data, nil
+		} else if !os.IsNotExist(err) {
+			log.Error("Unable to read file %q. Error: %v", localPath, err)
 		}
 	}
-	return nil, fmt.Errorf("asset file does not exist: %v", elems)
+	return nil, fmt.Errorf("local file does not exist: %v", elems)
 }

modules/options/dynamic.go

@@ -34,7 +34,7 @@ func Dir(name string) ([]string, error) {
 	return directories.AddAndGet(name, result), nil
 }
 
-// fileFromOptionsDir is a helper to read files from static or custom path.
+// fileFromOptionsDir is a helper to read files from custom or static path.
 func fileFromOptionsDir(elems ...string) ([]byte, error) {
 	return readFileFromLocal([]string{setting.CustomPath, setting.StaticRootPath}, "options", elems...)
 }

modules/options/static.go

@@ -8,8 +8,10 @@ package options
 import (
 	"fmt"
 	"io"
+	"path/filepath"
 
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
 )
 
 var directories = make(directorySet)
@@ -62,11 +64,12 @@ func AssetDir(dirName string) ([]string, error) {
 
 // fileFromOptionsDir is a helper to read files from custom path or bindata.
 func fileFromOptionsDir(elems ...string) ([]byte, error) {
+	// only try custom dir, no static dir
 	if data, err := readFileFromLocal([]string{setting.CustomPath}, "options", elems...); err == nil {
 		return data, nil
 	}
 
-	f, err := Assets.Open(name)
+	f, err := Assets.Open(util.SafePathRelX(elems...))
 	if err != nil {
 		return nil, err
 	}