Difference between Include, Extends, Use, Macro, Embed in Twig - php

Question

What is the difference between use and include in Twig?
Documentation:
include
The include statement includes a template and returns the rendered content of that template into the current one:
{% include 'header.html' %}
Body here...
{% include 'footer.html' %}
use
The use statement tells Twig to import the blocks defined in blocks.html into the current template (it's like macros, but for blocks):
blocks.html
{% block sidebar %}{% endblock %}
main.html
{% extends "base.html" %}
{% use "blocks.html" %}
{% block title %}{% endblock %}
{% block content %}{% endblock %}
Possible answer:
I think this should explain the difference:
include is to get all the code from an external file and import it
into your actual file at the right location of the call.
use is completely different as it parses the linked file to find a
particular section of code and then overwrites the blocks with the
same name, in your current file, with the one found in this external
file.
include is like "go find this file and render it with my page here".
use is "parse this other file to find block definitions to use instead
of my owns defined here".
If use command finds nothing matching the task, nothing is displayed
at all from this file.
Question
is the explanation correct? are there any other explanations to this difference?

Answer 1

After months, I am posting an answer for any further reference to this question. I also added some description for extends & import & macro & embed for more clearance:
There are various types of inheritance and code reuse in Twig:
Include
Main Goal: Code Reuse
Use Case: Using header.html.twig & footer.html.twig inside base.html.twig.
header.html.twig
<nav>
<div>Homepage</div>
<div>About</div>
</nav>
footer.html.twig
<footer>
<div>Copyright</div>
</footer>
base.html.twig
{% include 'header.html.twig' %}
<main>{% block main %}{% endblock %}</main>
{% include 'footer.html.twig' %}
Extends
Main Goal: Vertical Reuse
Use Case: Extending base.html.twig inside homepage.html.twig & about.html.twig.
base.html.twig
{% include 'header.html.twig' %}
<main>{% block main %}{% endblock %}</main>
{% include 'footer.html.twig' %}
homepage.html.twig
{% extends 'base.html.twig' %}
{% block main %}
<p>Homepage</p>
{% endblock %}
about.html.twig
{% extends 'base.html.twig' %}
{% block main %}
<p>About page</p>
{% endblock %}
Use
Main Goal: Horizontal Reuse
Use Case: sidebar.html.twig in single.product.html.twig & single.service.html.twig.
sidebar.html.twig
{% block sidebar %}<aside>This is sidebar</aside>{% endblock %}
single.product.html.twig
{% extends 'product.layout.html.twig' %}
{% use 'sidebar.html.twig' %}
{% block main %}<main>Product page</main>{% endblock %}
single.service.html.twig
{% extends 'service.layout.html.twig' %}
{% use 'sidebar.html.twig' %}
{% block main %}<main>Service page</main>{% endblock %}
Notes:
It's like macros, but for blocks.
The use tag only imports a template if it does not extend another template, if it does not define macros, and if the body is empty.
Macro
Main Goal: Reusable Markup with Variables
Use Case: A function which gets some variables and outputs some markup.
form.html.twig
{% macro input(name, value, type) %}
<input type="{{ type|default('text') }}" name="{{ name }}" value="{{ value|e }}" }}" />
{% endmacro %}
profile.service.html.twig
{% import "form.html.twig" as form %}
<form action="/login" method="post">
<div>{{ form.input('username') }}</div>
<div>{{ form.input('password') }}</div>
<div>{{ form.input('submit', 'Submit', 'submit') }}</div>
</form>
Embed
Main Goal: Block Overriding
Use Case: Embedding pagination.html.twig in product.table.html.twig & service.table.html.twig.
pagination.html.twig
<div id="pagination">
<div>{% block first %}{% endblock %}</div>
{% for i in (min + 1)..(max - 1) %}
<div>{{ i }}</div>
{% endfor %}
<div>{% block last %}{% endblock %}</div>
</div>
product.table.html.twig
{% set min, max = 1, products.itemPerPage %}
{% embed 'pagination.html.twig' %}
{% block first %}First Product Page{% endblock %}
{% block last %}Last Product Page{% endblock %}
{% endembed %}
service.table.html.twig
{% set min, max = 1, services.itemPerPage %}
{% embed 'pagination.html.twig' %}
{% block first %}First Service Page{% endblock %}
{% block last %}Last Service Page{% endblock %}
{% endembed %}
Please note that embedded file (pagination.html.twig) has access to the current context (min, max variables).
Also you may pass extra variables to the embedded file:
pagination.html.twig
<p>{{ count }} items</p>
<div>
<div>{% block first %}{% endblock %}</div>
{% for i in (min + 1)..(max - 1) %}
<div>{{ i }}</div>
{% endfor %}
<div>{% block last %}{% endblock %}</div>
</div>
product.table.html.twig
{% set min, max = 1, products|length %}
{% embed 'pagination.html.twig' with {'count': products|length } %}
{% block first %}First Product Page{% endblock %}
{% block last %}Last Product Page{% endblock %}
{% endembed %}
Note:
It has functionality of both Use & Include together.

Answer 2

Twig performance is spectacular, so chances are you will never care, but be aware that there is a significant difference between using embeds, includes, or macros.
I set up a little test project to demonstrate it: https://github.com/janklan/twig-benchmark
The readme has all the information you need if you're interested to know more, but the general result is, that for the same task executed in a loop of 100k iterations, the times between individual methods on my computer were as follows (lower is better)
embed: 4253ms
include: 3428ms
macro: 2695ms
By the way, the project I shared via Github up generates separate cache directories for each approach (embed/include/macro). If you want to see how different methods in Twig map to the compiled PHP, I recommend you check it out. If you wish to see the cache without having to run the project, check out a branch called with-cache