From 3624e09e56a4d6b317a71af0821bd0debfc439de Mon Sep 17 00:00:00 2001
From: Lunny Xiao <xiaolunwen@gmail.com>
Date: Thu, 17 Jul 2025 14:25:55 -0700
Subject: [PATCH] Fix bug when json with a real SQLType in the tag

---
 tags/parser.go      | 12 ++++++++----
 tags/parser_test.go | 38 ++++++++++++++++++++++++++++++++++++++
 tags/tag.go         | 14 +++++++++++---
 3 files changed, 57 insertions(+), 7 deletions(-)

diff --git a/tags/parser.go b/tags/parser.go
index 53ef0c10..cb14b6fc 100644
--- a/tags/parser.go
+++ b/tags/parser.go
@@ -250,10 +250,14 @@ func (parser *Parser) parseFieldWithTags(table *schemas.Table, fieldIndex int, f
 	}
 
 	if col.SQLType.Name == "" {
-		var err error
-		col.SQLType, err = parser.getSQLTypeByType(field.Type)
-		if err != nil {
-			return nil, err
+		if col.IsJSON {
+			col.SQLType = schemas.SQLType{Name: schemas.Text}
+		} else {
+			var err error
+			col.SQLType, err = parser.getSQLTypeByType(field.Type)
+			if err != nil {
+				return nil, err
+			}
 		}
 	}
 	if ctx.isUnsigned && col.SQLType.IsNumeric() && !strings.HasPrefix(col.SQLType.Name, "UNSIGNED") {
diff --git a/tags/parser_test.go b/tags/parser_test.go
index 434cfc07..839da3b0 100644
--- a/tags/parser_test.go
+++ b/tags/parser_test.go
@@ -617,3 +617,41 @@ func TestParseWithSQLType(t *testing.T) {
 	assert.EqualValues(t, "DATETIME", table.Columns()[3].SQLType.Name)
 	assert.EqualValues(t, "UUID", table.Columns()[4].SQLType.Name)
 }
+
+func TestParseWithJSONLongText(t *testing.T) {
+	parser := NewParser(
+		"db",
+		dialects.QueryDialect("mysql"),
+		names.GonicMapper{
+			"JSON": true,
+		},
+		names.GonicMapper{
+			"JSON": true,
+		},
+		caches.NewManager(),
+	)
+
+	type StructWithJSONLongText struct {
+		Col1 string `db:"LongText json"`
+	}
+
+	table, err := parser.Parse(reflect.ValueOf(new(StructWithJSONLongText)))
+	assert.NoError(t, err)
+	assert.EqualValues(t, "struct_with_json_long_text", table.Name)
+	assert.EqualValues(t, 1, len(table.Columns()))
+	assert.EqualValues(t, "col1", table.Columns()[0].Name)
+	assert.EqualValues(t, "LONGTEXT", table.Columns()[0].SQLType.Name)
+	assert.EqualValues(t, true, table.Columns()[0].IsJSON)
+
+	type StructWithJSONLongText2 struct {
+		Col1 string `db:"json"`
+	}
+
+	table, err = parser.Parse(reflect.ValueOf(new(StructWithJSONLongText2)))
+	assert.NoError(t, err)
+	assert.EqualValues(t, "struct_with_json_long_text2", table.Name)
+	assert.EqualValues(t, 1, len(table.Columns()))
+	assert.EqualValues(t, "col1", table.Columns()[0].Name)
+	assert.EqualValues(t, "TEXT", table.Columns()[0].SQLType.Name)
+	assert.EqualValues(t, true, table.Columns()[0].IsJSON)
+}
diff --git a/tags/tag.go b/tags/tag.go
index 55f0b7c7..dfb66a7e 100644
--- a/tags/tag.go
+++ b/tags/tag.go
@@ -124,10 +124,16 @@ var defaultTagHandlers = map[string]Handler{
 	"EXTENDS":  ExtendsTagHandler,
 	"UNSIGNED": UnsignedTagHandler,
 	"COLLATE":  CollateTagHandler,
+	"JSON":     JSONTagHandler,
+	"JSONB":    JSONTagHandler,
 }
 
 func init() {
 	for k := range schemas.SqlTypes {
+		// don't override default tag handlers
+		if _, ok := defaultTagHandlers[k]; ok {
+			continue
+		}
 		defaultTagHandlers[k] = SQLTypeTagHandler
 	}
 }
@@ -293,12 +299,14 @@ func CollateTagHandler(ctx *Context) error {
 	return nil
 }
 
+func JSONTagHandler(ctx *Context) error {
+	ctx.col.IsJSON = true
+	return nil
+}
+
 // SQLTypeTagHandler describes SQL Type tag handler
 func SQLTypeTagHandler(ctx *Context) error {
 	ctx.col.SQLType = schemas.SQLType{Name: ctx.tagUname}
-	if ctx.tagUname == "JSON" || ctx.tagUname == "JSONB" {
-		ctx.col.IsJSON = true
-	}
 	if len(ctx.params) == 0 {
 		return nil
 	}