@slfan1989 , have fixed the bug, please help review this pr when you have free time, thank you very much!

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@pan3793 Could you please review this change? Thank you very much!

@hfutatzhanghb Words like "fix the bug" make no sense, please explain the "why" of the change instead of "what" is the change.

Hi,@pan3793 . Thanks for reminding. Have updated in the description of this PR. Please see again~

@hfutatzhanghb I do not get your point about why a new rule "RegexpSingleline" is required, what is the issue in the current trunk do you want to fix?

@hfutatzhanghb I do not get your point about why a new rule "RegexpSingleline" is required, what is the issue in the current trunk do you want to fix?

@pan3793 As described in#7505 . In my local, checkstyle tools use trunk's checkstyle.xml can not detect blanks.

@pan3793 Here is a screenshot, which can detail the problem.

So this change intends to add a new checkstyle rule to forbid trailing spaces of lines, this generally is a good idea, but after I apply it (I change the severity to error to get the report) and check the current code base, there are more than 40k places that violate this rule

    <module name="RegexpSingleline">        <property name="format" value="\s+$"/>        <property name="severity" value="error"/>    </module>

mvn checkstyle:check | grep RegexpSingleline | wc -l   41890

If we add this rule, fixing those warnings will consume much time and introduce unnecessary commit history, but without real benefits.

Given such a situation, I suggest NOT adding such a rule, and just keeping things as-is.

@pan3793 Thanks for suggestioning. I got your concerns. Will close this PR.
Thanks@slfan1989 for helping.