Add rename_constraint operation (#293)

docs/README.md

@@ -31,6 +31,7 @@
     * [Drop table](#drop-table)
     * [Raw SQL](#raw-sql)
     * [Rename table](#rename-table)
+    * [Rename constraint](#rename-constraint)
     * [Set replica identity](#set-replica-identity)
 
 ## Concepts
@@ -686,6 +687,7 @@ See the [examples](../examples) directory for examples of each kind of operation
 * [Drop table](#drop-table)
 * [Raw SQL](#raw-sql)
 * [Rename table](#rename-table)
+* [Rename constraint](#rename-constraint)
 * [Set replica identity](#set-replica-identity)
 
 ### Add column
@@ -1112,6 +1114,28 @@ Example **rename table** migrations:
 
 * [04_rename_table.json](../examples/04_rename_table.json)
 
+
+### Rename constraint
+
+A rename constraint operation renames a constraint.
+
+**rename constraint** operations have this structure:
+
+```json
+{
+  "rename_constraint": {
+    "table": "table name",
+    "from": "old constraint name",
+    "to": "new constraint name"
+  }
+}
+```
+
+Example **rename constraint** migrations:
+
+* [33_rename_constraint.json](../examples/33_rename_constraint.json)
+
+
 ### Set replica identity
 
 A set replica identity operation sets the replica identity for a table. 

examples/33_rename_check_constraint.json

@@ -0,0 +1,12 @@
+{
+  "name": "33_rename_check_constraint",
+  "operations": [
+    {
+      "rename_constraint": {
+        "table": "people",
+        "from": "name_length",
+        "to": "name_length_check"
+      }
+    }
+  ]
+}

pkg/migrations/errors.go

@@ -137,6 +137,15 @@ func (e ConstraintDoesNotExistError) Error() string {
 	return fmt.Sprintf("constraint %q on table %q does not exist", e.Constraint, e.Table)
 }
 
+type ConstraintAlreadyExistsError struct {
+	Table      string
+	Constraint string
+}
+
+func (e ConstraintAlreadyExistsError) Error() string {
+	return fmt.Sprintf("constraint %q on table %q already exists", e.Constraint, e.Table)
+}
+
 type NoUpSQLAllowedError struct{}
 
 func (e NoUpSQLAllowedError) Error() string {

pkg/migrations/op_common.go

@@ -20,6 +20,7 @@ const (
 	OpNameAlterColumn        OpName = "alter_column"
 	OpNameCreateIndex        OpName = "create_index"
 	OpNameDropIndex          OpName = "drop_index"
+	OpNameRenameConstraint   OpName = "rename_constraint"
 	OpNameDropConstraint     OpName = "drop_constraint"
 	OpNameSetReplicaIdentity OpName = "set_replica_identity"
 	OpRawSQLName             OpName = "sql"
@@ -95,6 +96,9 @@ func (v *Operations) UnmarshalJSON(data []byte) error {
 		case OpNameDropColumn:
 			item = &OpDropColumn{}
 
+		case OpNameRenameConstraint:
+			item = &OpRenameConstraint{}
+
 		case OpNameDropConstraint:
 			item = &OpDropConstraint{}
 
@@ -175,6 +179,9 @@ func OperationName(op Operation) OpName {
 	case *OpDropColumn:
 		return OpNameDropColumn
 
+	case *OpRenameConstraint:
+		return OpNameRenameConstraint
+
 	case *OpDropConstraint:
 		return OpNameDropConstraint
 

pkg/migrations/op_rename_constraint.go

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package migrations
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+
+	"github.com/lib/pq"
+	"github.com/xataio/pgroll/pkg/schema"
+)
+
+var _ Operation = (*OpRenameConstraint)(nil)
+
+func (o *OpRenameConstraint) Start(ctx context.Context, conn *sql.DB, stateSchema string, s *schema.Schema, cbs ...CallbackFn) (*schema.Table, error) {
+	// no-op
+	return nil, nil
+}
+
+func (o *OpRenameConstraint) Complete(ctx context.Context, conn *sql.DB, s *schema.Schema) error {
+	// rename the constraint in the underlying table
+	_, err := conn.ExecContext(ctx, fmt.Sprintf("ALTER TABLE %s RENAME CONSTRAINT %s TO %s",
+		pq.QuoteIdentifier(o.Table),
+		pq.QuoteIdentifier(o.From),
+		pq.QuoteIdentifier(o.To)))
+	return err
+}
+
+func (o *OpRenameConstraint) Rollback(ctx context.Context, conn *sql.DB) error {
+	// no-op
+	return nil
+}
+
+func (o *OpRenameConstraint) Validate(ctx context.Context, s *schema.Schema) error {
+	table := s.GetTable(o.Table)
+
+	if !table.ConstraintExists(o.From) {
+		return ConstraintDoesNotExistError{Table: o.Table, Constraint: o.From}
+	}
+
+	if table.ConstraintExists(o.To) {
+		return ConstraintAlreadyExistsError{Table: o.Table, Constraint: o.To}
+	}
+
+	return nil
+}

pkg/migrations/op_rename_constraint_test.go

@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package migrations_test
+
+import (
+	"database/sql"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/xataio/pgroll/pkg/migrations"
+)
+
+func TestRenameConstraint(t *testing.T) {
+	t.Parallel()
+
+	addTableMigration := migrations.Migration{
+		Name: "01_add_table",
+		Operations: migrations.Operations{
+			&migrations.OpCreateTable{
+				Name: "users",
+				Columns: []migrations.Column{
+					{
+						Name: "id",
+						Type: "serial",
+						Pk:   ptr(true),
+					},
+					{
+						Name:     "username",
+						Type:     "text",
+						Nullable: ptr(false),
+						Check:    &migrations.CheckConstraint{Constraint: `LENGTH("username") <= 2048`, Name: "users_text_length_username"},
+					},
+				},
+			},
+		},
+	}
+
+	ExecuteTests(t, TestCases{{
+		name: "rename constraint",
+		migrations: []migrations.Migration{
+			addTableMigration,
+			{
+				Name: "02_rename_constraint",
+				Operations: migrations.Operations{
+					&migrations.OpAlterColumn{
+						Table:  "users",
+						Column: "username",
+						Name:   ptr("name"),
+					},
+					&migrations.OpRenameConstraint{
+						Table: "users",
+						From:  "users_text_length_username",
+						To:    "users_text_length_name",
+					},
+				},
+			},
+		},
+		afterStart: func(t *testing.T, db *sql.DB, schema string) {
+			// The column in the underlying table has not been renamed.
+			ColumnMustExist(t, db, schema, "users", "username")
+
+			// Insertions to the new column name in the new version schema should work.
+			MustInsert(t, db, schema, "02_rename_constraint", "users", map[string]string{"name": "alice"})
+
+			// Insertions to the old column name in the old version schema should work.
+			MustInsert(t, db, schema, "01_add_table", "users", map[string]string{"username": "bob"})
+
+			// The check constraint in the underlying table has not been renamed.
+			CheckConstraintMustExist(t, db, schema, "users", "users_text_length_username")
+
+			// The new check constraint in the underlying table has not been created.
+			CheckConstraintMustNotExist(t, db, schema, "users", "users_text_length_name")
+
+			// Data can be read from the view in the new version schema.
+			rows := MustSelect(t, db, schema, "02_rename_constraint", "users")
+			assert.Equal(t, []map[string]any{
+				{"id": 1, "name": "alice"},
+				{"id": 2, "name": "bob"},
+			}, rows)
+		},
+		afterRollback: func(t *testing.T, db *sql.DB, schema string) {
+			// no-op
+		},
+		afterComplete: func(t *testing.T, db *sql.DB, schema string) {
+			// The column in the underlying table has been renamed.
+			ColumnMustExist(t, db, schema, "users", "name")
+
+			// The check constraint in the underlying table has been renamed.
+			CheckConstraintMustExist(t, db, schema, "users", "users_text_length_name")
+
+			// The old check constraint in the underlying table has been dropped.
+			CheckConstraintMustNotExist(t, db, schema, "users", "users_text_length_username")
+
+			// Data can be read from the view in the new version schema.
+			rows := MustSelect(t, db, schema, "02_rename_constraint", "users")
+			assert.Equal(t, []map[string]any{
+				{"id": 1, "name": "alice"},
+				{"id": 2, "name": "bob"},
+			}, rows)
+		},
+	}})
+}

schema.json

@@ -348,6 +348,26 @@
       ],
       "type": "object"
     },
+    "OpRenameConstraint": {
+      "additionalProperties": false,
+      "description": "Rename constraint operation",
+      "properties": {
+        "from": {
+          "description": "Name of the constraint",
+          "type": "string"
+        },
+        "to": {
+          "description": "New name of the constraint",
+          "type": "string"
+        },
+        "table": {
+          "description": "Name of the table",
+          "type": "string"
+        }
+      },
+      "required": ["from", "to", "table"],
+      "type": "object"
+    },
     "OpRenameTable": {
       "additionalProperties": false,
       "description": "Rename table operation",