test(drawdb): add test for converting column types with modifiers

* Implement tests to ensure explicit type modifiers are preserved during conversion.
* Validate behavior for varchar, numeric, and custom vector types.

pkg/writers/gorm/type_mapper.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/pgsql"
 	"git.warky.dev/wdevs/relspecgo/pkg/writers"
 )
 
@@ -39,14 +40,7 @@ func (tm *TypeMapper) SQLTypeToGoType(sqlType string, notNull bool) string {
 // extractBaseType extracts the base type from a SQL type string
 // Examples: varchar(100) → varchar, numeric(10,2) → numeric
 func (tm *TypeMapper) extractBaseType(sqlType string) string {
-	sqlType = strings.ToLower(strings.TrimSpace(sqlType))
-
-	// Remove everything after '('
-	if idx := strings.Index(sqlType, "("); idx > 0 {
-		sqlType = sqlType[:idx]
-	}
-
-	return sqlType
+	return pgsql.CanonicalizeBaseType(pgsql.ExtractBaseTypeLower(sqlType))
 }
 
 // baseGoType returns the base Go type for a SQL type (not null)
@@ -209,9 +203,10 @@ func (tm *TypeMapper) BuildGormTag(column *models.Column, table *models.Table) s
 		// Include length, precision, scale if present
 		// Sanitize type to remove backticks
 		typeStr := writers.SanitizeStructTagValue(column.Type)
-		if column.Length > 0 {
+		hasExplicitTypeModifier := pgsql.HasExplicitTypeModifier(typeStr)
+		if !hasExplicitTypeModifier && column.Length > 0 {
 			typeStr = fmt.Sprintf("%s(%d)", typeStr, column.Length)
-		} else if column.Precision > 0 {
+		} else if !hasExplicitTypeModifier && column.Precision > 0 {
 			if column.Scale > 0 {
 				typeStr = fmt.Sprintf("%s(%d,%d)", typeStr, column.Precision, column.Scale)
 			} else {

pkg/writers/gorm/writer_test.go

@@ -14,12 +14,12 @@ func TestWriter_WriteTable(t *testing.T) {
 	// Create a simple table
 	table := models.InitTable("users", "public")
 	table.Columns["id"] = &models.Column{
-		Name:         "id",
-		Type:         "bigint",
-		NotNull:      true,
-		IsPrimaryKey: true,
+		Name:          "id",
+		Type:          "bigint",
+		NotNull:       true,
+		IsPrimaryKey:  true,
 		AutoIncrement: true,
-		Sequence:     1,
+		Sequence:      1,
 	}
 	table.Columns["email"] = &models.Column{
 		Name:     "email",
@@ -444,10 +444,10 @@ func TestWriter_MultipleHasManyRelationships(t *testing.T) {
 
 	// Verify all has-many relationships have unique names
 	hasManyExpectations := []string{
-		"RelRIDAPIProviderOrgLogins",      // Has many via Login
+		"RelRIDAPIProviderOrgLogins",       // Has many via Login
 		"RelRIDAPIProviderOrgFilepointers", // Has many via Filepointer
-		"RelRIDAPIProviderOrgAPIEvents",   // Has many via APIEvent
-		"RelRIDOwner",                     // Belongs to via rid_owner
+		"RelRIDAPIProviderOrgAPIEvents",    // Has many via APIEvent
+		"RelRIDOwner",                      // Belongs to via rid_owner
 	}
 
 	for _, exp := range hasManyExpectations {
@@ -669,3 +669,23 @@ func TestTypeMapper_SQLTypeToGoType(t *testing.T) {
 		})
 	}
 }
+
+func TestTypeMapper_BuildGormTag_PreservesExplicitTypeModifiers(t *testing.T) {
+	mapper := NewTypeMapper()
+
+	col := &models.Column{
+		Name:      "embedding",
+		Type:      "vector(1536)",
+		Length:    1536,
+		Precision: 0,
+		Scale:     0,
+	}
+
+	tag := mapper.BuildGormTag(col, nil)
+	if !strings.Contains(tag, "type:vector(1536)") {
+		t.Fatalf("expected explicit modifier to be preserved, got %q", tag)
+	}
+	if strings.Contains(tag, ")(") {
+		t.Fatalf("type modifier appears duplicated in %q", tag)
+	}
+}