Fix infinite recursion bug (fixes #68) (#74)

* Add regression test for recursion bug, #68

* Only allow slots to access slot nodelists provided to their immediate parent component to prevent infinite recursions.

* Fix import ordering bug in test

* Add slot.super to docs

Remove unused imports

* Bump version

Co-authored-by: rbeard0330 <@dul2k3BKW6m>

README.md

@@ -214,7 +214,7 @@ Components support something called slots. They work a lot like Django blocks, b
         {% slot "header" %}Calendar header{% endslot %}
     </div>
     <div class="body">
-        {% slot "body" %}Calendar body{% endslot %}
+        {% slot "body" %}Today's date is <span>{{ date }}</span>{% endslot %}
     </div>
 </div>
 ```
@@ -222,8 +222,8 @@ Components support something called slots. They work a lot like Django blocks, b
 When using the component, you specify what slots you want to fill and where you want to use the defaults from the template. It looks like this:
 
 ```htmldjango
-{% component_block "calendar" %}
-    {% slot "body" %}Today's date is <span>{{ date }}</span>{% endslot %}
+{% component_block "calendar" date="2020-06-06" %}
+    {% slot "body" %}Can you belive it's already <span>{{ date }}</span>??{% endslot %}
 {% endcomponent_block %}
 ```
 
@@ -235,7 +235,7 @@ Since the header block is unspecified, it's taken from the base template. If you
         Calendar header
     </div>
     <div class="body">
-        Today's date is <span>2020-06-06</span>
+        Can you believe it's already <span>2020-06-06</span>??
     </div>
 </div>
 
@@ -243,7 +243,28 @@ Since the header block is unspecified, it's taken from the base template. If you
 
 As you can see, component slots lets you write reusable containers, that you fill out when you use a component. This makes for highly reusable components, that can be used in different circumstances.
 
-# Component context
+If you want to include a slot's default content while adding additional content, you can call `slot.super` to insert the base content, which works similarly to `block.super`.  
+
+```htmldjango
+{% component_block "calendar" date="2020-06-06" %}
+    {% slot "body" %}{ slot.super }. Have a great day!{% endslot %}
+{% endcomponent_block %}
+``` 
+
+Produces:
+
+```html
+<div class="calendar-component">
+    <div class="header">
+        Calendar header
+    </div>
+    <div class="body">
+        Today's date is <span>2020-06-06</span>.  Have a great day!
+    </div>
+</div>
+```
+
+# Component context and scope
 
 By default, components can access context variables from the parent template, just like templates that are included with the `{% include %}` tag. Just like with `{% include %}`, if you don't want the component template to have access to the parent context, add `only` to the end of the `{% component %}` (or `{% component_block %}` tag):
 
@@ -255,6 +276,7 @@ NOTE: `{% csrf_token %}` tags need access to the top-level context, and they wil
 
 Components can also access the outer context in their context methods by accessing the property `outer_context`. 
 
+
 # Available settings
 
 All library settings are handled from a global COMPONENTS variable that is read from settings.py. By default you don't need it set, there are resonable defaults.

django_components/component.py

@@ -114,8 +114,7 @@ class Component(metaclass=SimplifiedInterfaceMediaDefiningClass):
     def render(self, context):
         template_name = self.template(context)
         instance_template = self.get_processed_template(template_name)
-        active_slots = {**context.get(ACTIVE_SLOT_CONTEXT_KEY, {}), **self.slots}
-        with context.update({ACTIVE_SLOT_CONTEXT_KEY: active_slots}):
+        with context.update({ACTIVE_SLOT_CONTEXT_KEY: self.slots}):
             return instance_template.render(context)
 
     class Media:

django_components/templatetags/component_tags.py

@@ -1,4 +1,3 @@
-import inspect
 from collections import defaultdict
 
 from django import template
@@ -7,7 +6,7 @@ from django.template.base import Node, NodeList, TemplateSyntaxError, TokenType
 from django.template.library import parse_bits
 from django.utils.safestring import mark_safe
 
-from django_components.component import ACTIVE_SLOT_CONTEXT_KEY, Component, registry
+from django_components.component import ACTIVE_SLOT_CONTEXT_KEY, registry
 from django_components.middleware import CSS_DEPENDENCY_PLACEHOLDER, JS_DEPENDENCY_PLACEHOLDER
 
 register = template.Library()

setup.py

@@ -3,7 +3,7 @@ import os
 
 from setuptools import find_packages, setup
 
-VERSION = '0.14'
+VERSION = '0.15'
 
 setup(
     name="django_components",

tests/test_component.py

@@ -215,3 +215,45 @@ class ComponentIsolationTests(SimpleTestCase):
             </custom-template>
         """
         )
+
+
+class RecursiveSlotNameTest(SimpleTestCase):
+    def setUp(self):
+        @component.register('outer')
+        class OuterComponent(component.Component):
+            def template(self, context):
+                return "slotted_template.html"
+
+        @component.register('inner')
+        class InnerComponent(component.Component):
+            def template(self, context):
+                return "slotted_template.html"
+
+    def test_no_infinite_recursion_when_slot_name_is_reused(self):
+        template = Template(
+            """
+            {% load component_tags %}
+            {% component_block "outer" %}
+                {% slot "header" %}
+                    {% component_block "inner" %}{% endcomponent_block %}
+                {% endslot %}
+            {% endcomponent_block %}
+        """
+        )
+
+        self.assertHTMLEqual(
+            template.render(Context({})),
+            """
+            <custom-template>
+                <header>
+                    <custom-template>
+                        <header>Default header</header>
+                        <main>Default main</main>
+                        <footer>Default footer</footer>
+                    </custom-template>
+                </header>
+                <main>Default main</main>
+                <footer>Default footer</footer>
+            </custom-template>
+            """
+        )

tests/test_templatetags.py

@@ -2,9 +2,8 @@ from textwrap import dedent
 
 from django.template import Context, Template, TemplateSyntaxError
 
-from django_components import component
-
 from .django_test_setup import *  # NOQA
+from django_components import component
 from .testutils import Django30CompatibleSimpleTestCase as SimpleTestCase