Django递归模板渲染期间的运行时错误

Question

I want to implement django recursive template rendering for getting users and their subordinates. However, I've got a ErrorRuntimeError at /admin/users/3 maximum recursion depth exceeded in instancecheck . I'm using django 1.9. The code is given below

The input is like that: [{name: 'user1@mail.com', id: 1, next: True}, {name: 'user2@mail.com', id: 2, next: True}, {name: 'user3@mail.com', id: 3, next: False}]

users_hierarchy.html

<ul>
{% for user in users %}
    <li>{{ user.name }}</li>
    {% if user.next %}
        <ul>
           {% include 'users/user_hierarchy.html' with data=user %}
        </ul>
    {% endif %}
{% endfor %}

I expect a html such as:

<ul>
<li>user1@mail.com
    <ul>
        <li>user2@mail.com
    <ul>
         <li>user3@mail.com</li>
    </ul>
        </li>  
    </ul>
</li>

What I am doing wrong?

Answer 1

I explain why you are in an infinite recursion

From djanto include template docs :

An included template is rendered within the context of the template that includes it.

That means you are iterating over users again and again:

<ul>
{% for user in users %}                 <-----(1)<------------------------<
    <li>{{ user.name }}</li>                                              |
    {% if user.next %}                                                    |
        <ul>                                                              |
           {% include 'users/user_hierarchy.html' with data=user %} --(2)->

At (1) you iterate over users . At first iteration you call the include (2). At this point you go to (1) (in nested included template) and start iteration again.