Ignore empty text node when parsing XML nodes

[nieqiurong]

When parsing XML, since nested nodes have line breaks by default, these nodes should not be parsed as text nodes and added, which will cause unnecessary heap space to be occupied.

The test project reduces the creation of this node, and the space occupied by this node is reduced from 1625KB to 748KB

[coveralls]

coverage: 87.33% (+0.02%) from 87.31%
when pulling 5c757a3 on nieqiurong:20241229
into e08b503 on mybatis:master.

[hazendaz]

@harawata Any concerns here? Its using trim so it handles all whitespace type which would probably be more appropriate title here.

[harawata]

Hello @nieqiurong ,

This seems like a good optimization without affecting the final SQL.
Nice work!

[nieqiurong]

thanks

[nieqiurong]

Hello @nieqiurong ,

This seems like a good optimization without affecting the final SQL. Nice work!

I think I missed compatibility considerations. If the label does not wrap, the statements will be connected together.

<!--parse: and id is not null and name is not null-->
<where>
    <if test="1==1">
        and id is not null
    </if>
    <if test="1==1">
        and name is not null
    </if>
</where>
<!-- parse: and id is not nulland name is not null-->
<where>
    <if test="1==1">and id is not null</if>
    <if test="1==1">and name is not null</if>
</where>

It may be better to change it to the following, so that there is no need to cooperate with Configuration#isShrinkWhitespacesInSql to remove line breaks

String data = child.getStringBody("").trim();
if (data.isEmpty()) {
  continue;
}
data += " ";

[epochcoder]

@nieqiurong The suggestion you posted would introduce extra spaces where it would not have normally been before this PR. In this case I think it is better to revert this. wdyt @harawata?

[nieqiurong]

@nieqiurong您发布的建议将引入额外的空间，而在此 PR 之前通常不会出现这些空间。在这种情况下，我认为最好恢复此状态。瓦迪特@harawata？

I agree with your suggestion, but can we add a configuration to decide whether to enable this operation, or provide an interface to support processing?

[harawata]

Yeah, adding extra space does not look great.

It's interesting that it only happens when <where> is used.
So, this is OK.

where 1=1
<if test="1==1">and id is not null</if>
<if test="1==1">and name is not null</if>

We might be able to workaround this in a different place.

In any case, if this PR changes the final SQL, it would be better to revert it and release 3.5.19.

[nieqiurong]

I agree, but can you consider removing \n? For example, some parser frameworks will have problems with continuous line breaks.

[harawata]

Can't you use shrinkWhitespacesInSql?

Find out why it only happens when <where> is used.
Then you might be able to find a solution.

[nieqiurong]

Thank you, I will look into it. You can roll back the code first to ensure compatibility.