Django - deployment on Heroku returns different HTML than local host

Question

I have a Django app that works great on localhost. When deployed the Heroku, for some reason the app returns different HTMLs. A few examples:

1. I have a form with button type submit. This is the template

        <button type="button" page="{{request.resolver_match.view_name}}" type="submit" id="bullets_submit"
            class="btn btn-primary px-5 py-2">
            Next Step
        </button>

In localhost everything works well. But, on Heroku, the HTML I receive is without the type="submit". Same button just without this attribute.

2. I have a for loop that iterates on a model and create a li

        <div class="h5 mx-4 px-3 bg-white" style="position: absolute; top: -20px;">
            About the role <a href="{% url 'app:responsibilities' description.pk %}" type="button" class="btn btn-outline-light px-2 text-muted border border-0"><i class="far fa-edit"></a></button>
        </div>
        <div class="border border-primary rounded shadow p-2 pt-3 m-2">
            <ul>
                {% for responsibility in description_responsibilities%}
                <li>{{responsibility}}</li>
                {% endfor %}
            </ul>
        </div>

On Heroku, even though the <i class="far fa-edit"> is clearly outside of the for loop, it still get generated several times in the HTML I receive from the server, as if it was inside the for loop.

Any idea what might cause this weird behavior? Or how I can debug it?

question from:https://stackoverflow.com/questions/65875280/django-deployment-on-heroku-returns-different-html-than-local-host

Answer 1

Found the reason. It was stupid (missing HTML tag).

What's interesting is that the page rendered nicely on my local Windows machine, but on Heroku, the issue appeared. It made it really hard to find what's wrong.

So I cloned my app to a linux shell and then the issue reproduced locally. From there it took 2 minutes to fix. I'm not sure why Windows django rendered a different page then linux.