append div with another div content using xpath - xpath

Question

I want to append div using xpath inheriting a parent template.
for ex.
this is parent template
<template id="parent_id">
<div id="header">
<div class="container">
<h1> HEADER </h1>
</div>
</div>
<div id="product">
<div class="container">
<!-- THERE IS SOME CONTENT -->
</div>
</div>
</template>
i want to change like this,
<template id="parent_id">
<div id="product">
<div class="inner">
<div class="container">
<!-- THERE IS SOME CONTENT -->
</div>
</div>
</div>
</template>
i try this,
<template id="product_custom" inherit_id="parent_id">
<xpath expr="//div[#id='product']" position="after">
<div class="inner">
</xpath>
</template>
while replace all content is easy or copy all content to custom template, but it not proper way. i want to wrap a div on content.

Answer 1

I think you cannot do that, because you are going either to override the content or to place your <div/> before, after on inside the selected element.
A simple solution will be to give the id="product" div the class inner by using position="attributes". Or if you really need this, a possible solution is:
replace id="product" with class="inner" with one override using attributes position
define your own template in a second override and call the original one inside it
You will end up with something like this:
<template id="my_parent" inherit_id="foo.parent_id">
<div id="product">
<t t-call="foo.parent_id" />
</div>
</template>
plus the override of the attributes. Never done something like this and the code above is not tested but it could work ;)