Convert ALTER TABLE foo RENAME TO bar SQL to pgroll operation (#513)

Convert SQL statements of the form:

```sql
ALTER TABLE foo RENAME TO bar
```

to the corresponding `OpRenameTable` operation:

```json
[
  {
    "rename_table": {
      "from": "foo",
      "to": "bar"
    }
  }
]
```

Part of #504

Author: andrew-farries

pkg/sql2pgroll/expect/rename_table.go

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package expect
+
+import "github.com/xataio/pgroll/pkg/migrations"
+
+var RenameTableOp1 = &migrations.OpRenameTable{
+	From: "foo",
+	To:   "bar",
+}

pkg/sql2pgroll/rename.go

@@ -7,14 +7,25 @@ import (
 	"github.com/xataio/pgroll/pkg/migrations"
 )
 
+// convertRenameStmt converts RenameStmt nodes to pgroll operations.
 func convertRenameStmt(stmt *pgq.RenameStmt) (migrations.Operations, error) {
-	if stmt.GetRelationType() != pgq.ObjectType_OBJECT_TABLE {
-		return nil, nil
-	}
-	if stmt.GetRenameType() != pgq.ObjectType_OBJECT_COLUMN {
+	switch stmt.GetRenameType() {
+	case pgq.ObjectType_OBJECT_TABLE:
+		return convertRenameTable(stmt)
+	case pgq.ObjectType_OBJECT_COLUMN:
+		return convertRenameColumn(stmt)
+	default:
 		return nil, nil
 	}
+}
 
+// convertRenameColumn converts SQL statements like:
+//
+// `ALTER TABLE foo RENAME COLUMN a TO b`
+// `ALTER TABLE foo RENAME a TO b`
+//
+// to an OpAlterColumn operation.
+func convertRenameColumn(stmt *pgq.RenameStmt) (migrations.Operations, error) {
 	return migrations.Operations{
 		&migrations.OpAlterColumn{
 			Table:  stmt.GetRelation().GetRelname(),
@@ -23,3 +34,17 @@ func convertRenameStmt(stmt *pgq.RenameStmt) (migrations.Operations, error) {
 		},
 	}, nil
 }
+
+// convertRenameTable converts SQL statements like:
+//
+// `ALTER TABLE foo RENAME TO bar`
+//
+// to an OpRenameTable operation.
+func convertRenameTable(stmt *pgq.RenameStmt) (migrations.Operations, error) {
+	return migrations.Operations{
+		&migrations.OpRenameTable{
+			From: stmt.GetRelation().GetRelname(),
+			To:   stmt.GetNewname(),
+		},
+	}, nil
+}

pkg/sql2pgroll/rename_test.go

@@ -12,7 +12,7 @@ import (
 	"github.com/xataio/pgroll/pkg/sql2pgroll/expect"
 )
 
-func TestConvertRenameColumnStatements(t *testing.T) {
+func TestConvertRenameStatements(t *testing.T) {
 	t.Parallel()
 
 	tests := []struct {
@@ -27,6 +27,10 @@ func TestConvertRenameColumnStatements(t *testing.T) {
 			sql:        "ALTER TABLE foo RENAME a TO b",
 			expectedOp: expect.AlterColumnOp4,
 		},
+		{
+			sql:        "ALTER TABLE foo RENAME TO bar",
+			expectedOp: expect.RenameTableOp1,
+		},
 	}
 
 	for _, tc := range tests {