feat: null safety

common/nullSafetyCheck.go

@@ -0,0 +1,68 @@
+package common
+
+import (
+	"errors"
+	"github.com/fatih/structtag"
+	"go/ast"
+	"golang.org/x/tools/go/analysis"
+)
+
+func isPointerType(typeExpr ast.Expr) bool {
+	isPointer := false
+	if _, ok := typeExpr.(*ast.StarExpr); ok {
+		isPointer = true
+	}
+	return isPointer
+}
+
+func isGormValueNullable(tags *structtag.Tags) (*bool, error) {
+	gormTag, err := tags.Get("gorm")
+	if gormTag == nil {
+		return nil, nil
+	}
+
+	gormTag.Options = append([]string{gormTag.Name}, gormTag.Options...)
+
+	if err != nil {
+		return nil, nil
+	}
+
+	nullTagExist := gormTag.HasOption("null")
+	notNullTagExist := gormTag.HasOption("not null")
+
+	if nullTagExist == notNullTagExist && nullTagExist == true {
+		return nil, errors.New(`tags "null" and "not null" are specified at one field`)
+	}
+
+	if nullTagExist {
+		return PointerOf(true), nil
+	} else if notNullTagExist {
+		return PointerOf(false), nil
+	} else {
+		return PointerOf(false), nil
+	}
+}
+
+func CheckFieldNullConsistency(pass analysis.Pass, field ast.Field, structName string, structTags string) {
+	tags, err := structtag.Parse(structTags)
+	if err != nil {
+		pass.Reportf(field.Pos(), "Invalid structure tag: %s", err)
+	}
+	if tags == nil {
+		return
+	}
+
+	isFieldNullable := isPointerType(field.Type)
+	isColumnNullable, err := isGormValueNullable(tags)
+
+	if err != nil {
+		pass.Reportf(field.Pos(), "Null safety error: %s", err)
+	}
+	if isColumnNullable == nil {
+		return
+	}
+
+	if isFieldNullable != *isColumnNullable {
+		pass.Reportf(field.Pos(), "Null safety error in \"%s\" model, field \"%s\": column nullable policy doesn't match to tag nullable policy", structName, field.Names[0].Name)
+	}
+}