From a6e90777e3606e88af26ef2cffd47388eb58c4f0 Mon Sep 17 00:00:00 2001
From: truongns <struong.ng@gmail.com>
Date: Tue, 7 Mar 2023 18:10:25 +0900
Subject: [PATCH] Fix #4930 workaround for databases that support
 auto-increment in composite primary key.

---
 schema/schema.go      | 10 ++++++++++
 schema/schema_test.go | 27 +++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/schema/schema.go b/schema/schema.go
index b34383bd..fab1dcef 100644
--- a/schema/schema.go
+++ b/schema/schema.go
@@ -225,6 +225,16 @@ func ParseWithSpecialTableName(dest interface{}, cacheStore *sync.Map, namer Nam
 		schema.PrioritizedPrimaryField = schema.PrimaryFields[0]
 	}
 
+	// If there are multiple primary keys, the AUTOINCREMENT field is prioritized
+	if schema.PrioritizedPrimaryField == nil && len(schema.PrimaryFields) > 1 {
+		for _, field := range schema.PrimaryFields {
+			if _, ok := field.TagSettings["AUTOINCREMENT"]; ok {
+				schema.PrioritizedPrimaryField = field
+				break
+			}
+		}
+	}
+
 	for _, field := range schema.PrimaryFields {
 		schema.PrimaryFieldDBNames = append(schema.PrimaryFieldDBNames, field.DBName)
 	}
diff --git a/schema/schema_test.go b/schema/schema_test.go
index 8a752fb7..b263974d 100644
--- a/schema/schema_test.go
+++ b/schema/schema_test.go
@@ -293,3 +293,30 @@ func TestEmbeddedStructForCustomizedNamingStrategy(t *testing.T) {
 		})
 	}
 }
+
+func TestCompositePrimaryKeyWithAutoIncrement(t *testing.T) {
+	type Product struct {
+		ProductID    uint `gorm:"primaryKey;autoIncrement"`
+		LanguageCode uint `gorm:"primaryKey"`
+		Code         string
+		Name         string
+	}
+
+	product, err := schema.Parse(&Product{}, &sync.Map{}, schema.NamingStrategy{})
+	if err != nil {
+		t.Fatalf("failed to parse product struct with composite primary key, got error %v", err)
+	}
+
+	prioritizedPrimaryField := schema.Field{
+		Name: "ProductID", DBName: "product_id", BindNames: []string{"ProductID"}, DataType: schema.Uint, PrimaryKey: true, Size: 64, HasDefaultValue: true, AutoIncrement: true, TagSettings: map[string]string{"PRIMARYKEY": "PRIMARYKEY", "AUTOINCREMENT": "AUTOINCREMENT"},
+	}
+
+	product.Fields = []*schema.Field{product.PrioritizedPrimaryField}
+
+	checkSchemaField(t, product, &prioritizedPrimaryField, func(f *schema.Field) {
+		f.Creatable = true
+		f.Updatable = true
+		f.Readable = true
+	})
+
+}