TCC开启Fence二阶段Cancel可能不会执行


上图中，一阶段业务逻辑如果有异常，会回滚，一阶段的fence_log实际上插入失败了，在回滚过程中，会判断没有fence_log，不执行cancel逻辑，如下图
如果一阶段的业务全是能够被Spring事务管理的操作还可以，如果不是可以被Spring事务管理的操作，这里应该会有问题

Start by tracing the TCC rollback path described in the issue, focusing on the fence_log check and the second-phase cancel decision. Reproduce a first-phase failure involving operations outside Spring transaction management, then verify that the cancel logic still executes when the fence_log insert failed.

Written by the indexing model from the issue text.