zypper rollback behavior when repository list changes after a failed upgrade

Goal: define how zypper rollback should treat repository modifications that occur after a transaction fails during an upgrade.

Uncertainty: the current documentation does not state whether the rollback operation must revert to the original repository set, allow the current set to influence package resolution, or require an explicit administrator choice, leaving the safe recovery path ambiguous.

Should zypper automatically use the repository list recorded at the start of the transaction?
Should it warn when the active repository list differs from the stored list before proceeding?
Should an explicit flag or configuration option be required to override the original repository set?