在使用jenkins Email-ext plugin發送郵件時，項目中使用了SVN去同步，發現每次有同步，都會發送郵件，現只想SVN只更新，不發送郵件通知，這就要在Pre-send中做修改
看看官網說明：
Pre-send Script The pre-send script is a feature which allows you to write a script that can modify the MimeMessage object prior to sending. This would allow adding custom headers, modifying the body, etc. Predefined variables include: msg - the MimeMessage object which can be modified logger - a PrintStream and will write to the job's log. build - the build this message belongs to cancel - a boolean, which when set to true will cancel the sending of the email
只官網中可以看到cancel可以滿足我們的需求，只要設置cancel為true就行，怎么設置呢？
下面這樣寫嗎？
Jenkins > Manage > script if (build.changeSet.emptySet) cancel=true;
好像也不對，在多次嘗試后，發出其實只需要這樣寫就可以
如下圖：
