fix(pgsql): handle default values for array types in migrations

* update default value quoting logic for PostgreSQL
* add tests for array default value handling

pkg/writers/pgsql/migration_writer.go

@@ -329,8 +329,12 @@ func (w *MigrationWriter) generateAlterTableScripts(schema *models.Schema, model
 			// Column doesn't exist, add it
 			defaultVal := ""
 			if modelCol.Default != nil {
+				if value, ok := modelCol.Default.(string); ok {
+					defaultVal = writers.QuoteDefaultValue(value, modelCol.Type)
+				} else {
 					defaultVal = fmt.Sprintf("%v", modelCol.Default)
 				}
+			}
 
 			sql, err := w.executor.ExecuteAddColumn(AddColumnData{
 				SchemaName: schema.Name,
@@ -382,8 +386,12 @@ func (w *MigrationWriter) generateAlterTableScripts(schema *models.Schema, model
 				setDefault := modelCol.Default != nil
 				defaultVal := ""
 				if setDefault {
+					if value, ok := modelCol.Default.(string); ok {
+						defaultVal = writers.QuoteDefaultValue(value, modelCol.Type)
+					} else {
 						defaultVal = fmt.Sprintf("%v", modelCol.Default)
 					}
+				}
 
 				sql, err := w.executor.ExecuteAlterColumnDefault(AlterColumnDefaultData{
 					SchemaName:   schema.Name,

pkg/writers/pgsql/migration_writer_test.go

@@ -57,6 +57,46 @@ func TestWriteMigration_NewTable(t *testing.T) {
 	}
 }
 
+func TestWriteMigration_ArrayDefault(t *testing.T) {
+	current := models.InitDatabase("testdb")
+	currentSchema := models.InitSchema("public")
+	current.Schemas = append(current.Schemas, currentSchema)
+
+	model := models.InitDatabase("testdb")
+	modelSchema := models.InitSchema("public")
+
+	table := models.InitTable("plans", "public")
+
+	tagsCol := models.InitColumn("tags", "plans", "public")
+	tagsCol.Type = "text[]"
+	tagsCol.NotNull = true
+	tagsCol.Default = "''{}''"
+	table.Columns["tags"] = tagsCol
+
+	modelSchema.Tables = append(modelSchema.Tables, table)
+	model.Schemas = append(model.Schemas, modelSchema)
+
+	var buf bytes.Buffer
+	writer, err := NewMigrationWriter(&writers.WriterOptions{})
+	if err != nil {
+		t.Fatalf("Failed to create writer: %v", err)
+	}
+	writer.writer = &buf
+
+	err = writer.WriteMigration(model, current)
+	if err != nil {
+		t.Fatalf("WriteMigration failed: %v", err)
+	}
+
+	output := buf.String()
+	if !strings.Contains(output, "tags text[] DEFAULT '{}' NOT NULL") {
+		t.Fatalf("expected normalized array default in migration, got:\n%s", output)
+	}
+	if strings.Contains(output, "'''{}'''") {
+		t.Fatalf("migration still contains triple-quoted array default:\n%s", output)
+	}
+}
+
 func TestWriteMigration_WithAudit(t *testing.T) {
 	// Current database (empty)
 	current := models.InitDatabase("testdb")

pkg/writers/pgsql/templates.go

@@ -8,6 +8,7 @@ import (
 	"text/template"
 
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
 )
 
 //go:embed templates/*.tmpl
@@ -495,8 +496,12 @@ func BuildCreateTableData(schemaName string, table *models.Table) CreateTableDat
 			NotNull: col.NotNull,
 		}
 		if col.Default != nil {
+			if value, ok := col.Default.(string); ok {
+				colData.Default = writers.QuoteDefaultValue(value, col.Type)
+			} else {
 				colData.Default = fmt.Sprintf("%v", col.Default)
 			}
+		}
 		columns = append(columns, colData)
 	}
 

pkg/writers/pgsql/writer.go

@@ -523,15 +523,7 @@ func (w *Writer) generateColumnDefinition(col *models.Column) string {
 	if col.Default != nil {
 		switch v := col.Default.(type) {
 		case string:
-			// Strip backticks - DBML uses them for SQL expressions but PostgreSQL doesn't
-			cleanDefault := stripBackticks(v)
-			if strings.HasPrefix(cleanDefault, "nextval") || strings.HasPrefix(cleanDefault, "CURRENT_") || strings.Contains(cleanDefault, "()") {
-				parts = append(parts, fmt.Sprintf("DEFAULT %s", cleanDefault))
-			} else if cleanDefault == "true" || cleanDefault == "false" {
-				parts = append(parts, fmt.Sprintf("DEFAULT %s", cleanDefault))
-			} else {
-				parts = append(parts, fmt.Sprintf("DEFAULT '%s'", escapeQuote(cleanDefault)))
-			}
+			parts = append(parts, fmt.Sprintf("DEFAULT %s", writers.QuoteDefaultValue(stripBackticks(v), col.Type)))
 		case bool:
 			parts = append(parts, fmt.Sprintf("DEFAULT %v", v))
 		default:

pkg/writers/writer.go

@@ -110,8 +110,12 @@ func SanitizeFilename(name string) string {
 // Examples (bigint):    "0"            → "0"
 // Examples (timestamp): "now()"        → "now()"   (function call – never quoted)
 func QuoteDefaultValue(value, sqlType string) string {
+	value = strings.TrimSpace(value)
+
 	// Function calls are never quoted regardless of column type.
-	if strings.Contains(value, "(") || strings.Contains(value, ")") {
+	if strings.Contains(value, "(") || strings.Contains(value, ")") ||
+		strings.Contains(value, "::") ||
+		strings.HasPrefix(strings.ToUpper(value), "ARRAY[") {
 		return value
 	}
 
@@ -121,6 +125,16 @@ func QuoteDefaultValue(value, sqlType string) string {
 		baseType = baseType[:idx]
 	}
 
+	if isArraySQLType(baseType) {
+		if arrayLiteral, ok := normalizeArrayDefaultLiteral(value); ok {
+			return quoteSQLLiteral(arrayLiteral)
+		}
+	}
+
+	if isQuotedSQLLiteral(value) {
+		return value
+	}
+
 	// Types whose default values must NOT be quoted.
 	unquotedTypes := map[string]bool{
 		// Integer types
@@ -154,7 +168,32 @@ func QuoteDefaultValue(value, sqlType string) string {
 
 	// Everything else (text, varchar, char, uuid, date, time, timestamp, json, …)
 	// is treated as a quoted literal.
-	return "'" + value + "'"
+	return quoteSQLLiteral(value)
+}
+
+func isArraySQLType(sqlType string) bool {
+	return strings.HasSuffix(sqlType, "[]")
+}
+
+func normalizeArrayDefaultLiteral(value string) (string, bool) {
+	switch {
+	case strings.HasPrefix(value, "''{") && strings.HasSuffix(value, "}''"):
+		return value[2 : len(value)-2], true
+	case strings.HasPrefix(value, "'{") && strings.HasSuffix(value, "}'"):
+		return value[1 : len(value)-1], true
+	case strings.HasPrefix(value, "{") && strings.HasSuffix(value, "}"):
+		return value, true
+	default:
+		return "", false
+	}
+}
+
+func isQuotedSQLLiteral(value string) bool {
+	return len(value) >= 2 && strings.HasPrefix(value, "'") && strings.HasSuffix(value, "'")
+}
+
+func quoteSQLLiteral(value string) string {
+	return "'" + strings.ReplaceAll(value, "'", "''") + "'"
 }
 
 // SanitizeStructTagValue sanitizes a value to be safely used inside Go struct tags.

pkg/writers/writer_test.go

@@ -0,0 +1,54 @@
+package writers
+
+import "testing"
+
+func TestQuoteDefaultValue(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name    string
+		value   string
+		sqlType string
+		want    string
+	}{
+		{
+			name:    "text default is quoted",
+			value:   "active",
+			sqlType: "text",
+			want:    "'active'",
+		},
+		{
+			name:    "array default from bare literal is quoted once",
+			value:   "{}",
+			sqlType: "text[]",
+			want:    "'{}'",
+		},
+		{
+			name:    "array default from quoted literal is preserved",
+			value:   "'{}'",
+			sqlType: "text[]",
+			want:    "'{}'",
+		},
+		{
+			name:    "array default from double quoted literal is normalized",
+			value:   "''{}''",
+			sqlType: "text[]",
+			want:    "'{}'",
+		},
+		{
+			name:    "function default is left alone",
+			value:   "now()",
+			sqlType: "timestamptz",
+			want:    "now()",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := QuoteDefaultValue(tt.value, tt.sqlType)
+			if got != tt.want {
+				t.Fatalf("QuoteDefaultValue(%q, %q) = %q, want %q", tt.value, tt.sqlType, got, tt.want)
+			}
+		})
+	}
+}