refactor: do not track transaction done status

package_test.go

@@ -1118,18 +1118,11 @@ func (s *PackageSuite) TestTransactionErrors(c *C) {
 	// Test error when running query after rollback against the public error variable.
 	tx, err = db.Begin(ctx, nil)
 	c.Assert(err, IsNil)
-	// Create Query.
-	q = tx.Query(ctx, insertStmt, &derek)
-	// Rollback.
+
 	err = tx.Rollback()
 	c.Assert(err, IsNil)
+
 	err = tx.Query(ctx, insertStmt, &derek).Run()
-	// Check against sqlair package error.
-	if !errors.Is(err, sqlair.ErrTXDone) {
-		c.Errorf("expected %q, got %q", sqlair.ErrTXDone, err)
-	}
-	err = q.Run()
-	// Check against sql package error.
 	if !errors.Is(err, sql.ErrTxDone) {
 		c.Errorf("expected %q, got %q", sql.ErrTxDone, err)
 	}

sqlair.go

@@ -8,7 +8,6 @@ import (
 	"database/sql"
 	"fmt"
 	"reflect"
-	"sync/atomic"
 
 	"github.com/canonical/sqlair/internal/expr"
 )
@@ -33,7 +32,6 @@ type M map[string]any
 type S []any
 
 var ErrNoRows = sql.ErrNoRows
-var ErrTXDone = sql.ErrTxDone
 
 // stmtCache stores the driver prepared statements associated to the SQLair
 // Statement objects.
@@ -413,18 +411,6 @@ func (q *Query) GetAll(sliceArgs ...any) (err error) {
 type TX struct {
 	sqltx *sql.Tx
 	db    *DB
-	done  int32
-}
-
-func (tx *TX) isDone() bool {
-	return atomic.LoadInt32(&tx.done) == 1
-}
-
-func (tx *TX) setDone() error {
-	if !atomic.CompareAndSwapInt32(&tx.done, 0, 1) {
-		return ErrTXDone
-	}
-	return nil
 }
 
 // Begin starts a transaction. A transaction must be ended
@@ -442,20 +428,12 @@ func (db *DB) Begin(ctx context.Context, opts *TXOptions) (*TX, error) {
 
 // Commit commits the transaction.
 func (tx *TX) Commit() error {
-	err := tx.setDone()
-	if err == nil {
-		err = tx.sqltx.Commit()
-	}
-	return err
+	return tx.sqltx.Commit()
 }
 
 // Rollback aborts the transaction.
 func (tx *TX) Rollback() error {
-	err := tx.setDone()
-	if err == nil {
-		err = tx.sqltx.Rollback()
-	}
-	return err
+	return tx.sqltx.Rollback()
 }
 
 // TXOptions holds the transaction options to be used in [DB.Begin].
@@ -483,9 +461,6 @@ func (tx *TX) Query(ctx context.Context, s *Statement, inputArgs ...any) *Query
 	if ctx == nil {
 		ctx = context.Background()
 	}
-	if tx.isDone() {
-		return &Query{ctx: ctx, err: ErrTXDone}
-	}
 
 	pq, err := s.te.BindInputs(inputArgs...)
 	if err != nil {