make merge compatible with an existing transaction

templates/23_merge.tpl

@@ -4,32 +4,42 @@
 {{- else -}}
 	{{- $dot := . }}
 // Merge combines two {{$tableNamePlural}} into one. The primary record will be kept, and the secondary will be deleted.
-func Merge{{$tableNamePlural}}(exec boil.Executor, primaryID uint64, secondaryID uint64) error {
+func Merge{{$tableNamePlural}}(exec boil.Executor, primaryID uint64, secondaryID uint64) (err error) {
+	tx, ok := exec.(boil.Transactor)
+	if !ok {
 		txdb, ok := exec.(boil.Beginner)
 		if !ok {
 			return errors.New("database does not support transactions")
 		}
 
-	tx, txErr := txdb.Begin()
-	if txErr != nil {
-		return txErr
+		tx, err = txdb.Begin()
+		if err != nil {
+			return err
+		}
+
+		defer func() {
+			if p := recover(); p != nil {
+				tx.Rollback()
+				panic(p) // Rollback, then propagate panic
+			} else if err != nil {
+				tx.Rollback()
+			} else {
+				err = tx.Commit()
+			}
+		}()
 	}
 
   primary, err := Find{{$tableNameSingular}}(tx, primaryID)
   if err != nil {
-    tx.Rollback()
     return err
-  }
-	if primary == nil {
+  } else if primary == nil {
 		return errors.New("Primary {{$tableNameSingular}} not found")
 	}
 
   secondary, err := Find{{$tableNameSingular}}(tx, secondaryID)
   if err != nil {
-    tx.Rollback()
     return err
-  }
-	if secondary == nil {
+  } else if secondary == nil {
 		return errors.New("Secondary {{$tableNameSingular}} not found")
 	}
 
@@ -59,9 +69,13 @@ func Merge{{$tableNamePlural}}(exec boil.Executor, primaryID uint64, secondaryID
     {{- end }}
   }
 
-  err = mergeModels(tx, primaryID, secondaryID, foreignKeys, conflictingKeys)
+  sqlTx, ok := tx.(*sql.Tx)
+  if !ok {
+    return errors.New("tx must be an sql.Tx")
+  }
+
+  err = mergeModels(sqlTx, primaryID, secondaryID, foreignKeys, conflictingKeys)
   if err != nil {
-    tx.Rollback()
     return err
   }
 
@@ -80,17 +94,14 @@ func Merge{{$tableNamePlural}}(exec boil.Executor, primaryID uint64, secondaryID
 
 	err = primary.Update(tx)
 	if err != nil {
-		tx.Rollback()
 		return errors.WithStack(err)
 	}
 
 	err = secondary.Delete(tx)
 	if err != nil {
-		tx.Rollback()
 		return errors.WithStack(err)
 	}
 
-  tx.Commit()
   return nil
 }