sql/migratespec: support modify_table and add_column (#246)

internal/integration/hclsqlspec/migrate_test.go

@@ -0,0 +1,39 @@
+package hclsqlspec
+
+import (
+	"testing"
+
+	"ariga.io/atlas/schema/schemaspec/schemahcl"
+	"ariga.io/atlas/sql/sqlspec"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMigrate(t *testing.T) {
+	f := `
+modify_table {
+	table = "users"
+	add_column {
+		column "id" {
+			type = "int"
+		}
+	}
+}
+`
+	var test struct {
+		Changes []sqlspec.Change `spec:""`
+	}
+	err := schemahcl.Unmarshal([]byte(f), &test)
+	require.NoError(t, err)
+	require.EqualValues(t, &sqlspec.ModifyTable{
+		Table: "users",
+		Changes: []sqlspec.Change{
+			&sqlspec.AddColumn{
+				Column: &sqlspec.Column{
+					Name:     "id",
+					Null:     false,
+					TypeName: "int",
+				},
+			},
+		},
+	}, test.Changes[0])
+}

sql/sqlspec/migratespec.go

@@ -0,0 +1,31 @@
+package sqlspec
+
+import (
+	"ariga.io/atlas/schema/schemaspec"
+)
+
+type (
+	// Change is the interface implemented by change specifications. Change instances are supposed
+	// to be mappable to schema.Change instances.
+	Change interface {
+		change()
+	}
+
+	// ModifyTable is a specification for a schema.ModifyTable.
+	ModifyTable struct {
+		Change
+		Table   string   `spec:"table"`
+		Changes []Change `spec:""`
+	}
+
+	// AddColumn is a specification for a schema.AddColumn.
+	AddColumn struct {
+		Change
+		Column *Column `spec:"column"`
+	}
+)
+
+func init() {
+	schemaspec.Register("modify_table", &ModifyTable{})
+	schemaspec.Register("add_column", &AddColumn{})
+}