Move slot rendering to BoundComponent and remove Slots abstraction (#138)

Author: joshuadavidthomas

CHANGELOG.md

@@ -18,6 +18,19 @@ and this project attempts to adhere to [Semantic Versioning](https://semver.org/
 
 ## [Unreleased]
 
+### Changed
+
+- **Internal**: Refactored slot handling logic by moving slot processing from `BirdNode` to `BoundComponent`.
+- **Internal**: Simplified component context management in `BirdNode` by offloading context prep to `BoundComponent`.
+
+### Removed
+
+- **Internal**: Removed standalone `Slots` dataclass abstraction in favor of handling in `BoundComponent`.
+
+### Fixed
+
+- Fixed default slot content handling when using `only` keyword for component context isolation.
+
 ## [0.12.0]
 
 ### Added

src/django_bird/components.py

@@ -5,11 +5,15 @@
 from hashlib import md5
 from pathlib import Path
 from threading import Lock
+from typing import TYPE_CHECKING
 
 from cachetools import LRUCache
 from django.apps import apps
 from django.conf import settings
 from django.template.backends.django import Template as DjangoTemplate
+from django.template.base import Node
+from django.template.base import NodeList
+from django.template.base import TextNode
 from django.template.context import Context
 from django.template.engine import Engine
 from django.template.exceptions import TemplateDoesNotExist
@@ -19,11 +23,16 @@
 from django_bird.params import Params
 from django_bird.params import Value
 from django_bird.staticfiles import Asset
+from django_bird.templatetags.tags.slot import DEFAULT_SLOT
+from django_bird.templatetags.tags.slot import SlotNode
 
 from .conf import app_settings
 from .staticfiles import AssetType
 from .templates import get_template_names
 
+if TYPE_CHECKING:
+    from django_bird.templatetags.tags.bird import BirdNode
+
 
 @dataclass(frozen=True, slots=True)
 class Component:
@@ -37,9 +46,9 @@ def get_asset(self, asset_filename: str) -> Asset | None:
                 return asset
         return None
 
-    def get_bound_component(self, attrs: list[Param]):
-        params = Params.with_attrs(attrs)
-        return BoundComponent(component=self, params=params)
+    def get_bound_component(self, node: BirdNode):
+        params = Params.with_attrs(node.attrs)
+        return BoundComponent(component=self, params=params, nodelist=node.nodelist)
 
     @property
     def data_attribute_name(self):
@@ -108,6 +117,7 @@ def next(self, component: Component) -> int:
 class BoundComponent:
     component: Component
     params: Params
+    nodelist: NodeList | None
     _sequence: SequenceGenerator = field(default_factory=SequenceGenerator)
 
     def render(self, context: Context):
@@ -123,15 +133,46 @@ def render(self, context: Context):
 
         props = self.params.render_props(self.component.nodelist, context)
         attrs = self.params.render_attrs(context)
+        slots = self.fill_slots(context)
 
         with context.push(
             **{
                 "attrs": attrs,
                 "props": props,
+                "slot": slots.get(DEFAULT_SLOT),
+                "slots": slots,
             }
         ):
             return self.component.template.template.render(context)
 
+    def fill_slots(self, context: Context):
+        if self.nodelist is None:
+            return {
+                DEFAULT_SLOT: None,
+            }
+
+        slot_nodes = {
+            node.name: node for node in self.nodelist if isinstance(node, SlotNode)
+        }
+        default_nodes = NodeList(
+            [node for node in self.nodelist if not isinstance(node, SlotNode)]
+        )
+
+        slots: dict[str, Node | NodeList] = {
+            DEFAULT_SLOT: default_nodes,
+            **slot_nodes,
+        }
+
+        if context.get("slots"):
+            for name, content in context["slots"].items():
+                if name not in slots or not slots.get(name):
+                    slots[name] = TextNode(str(content))
+
+        if not slots[DEFAULT_SLOT] and "slot" in context:
+            slots[DEFAULT_SLOT] = TextNode(context["slot"])
+
+        return {name: node.render(context) for name, node in slots.items() if node}
+
     @property
     def id(self):
         return str(self._sequence.next(self.component))

src/django_bird/slots.py

@@ -1,8 +1,6 @@
 # pyright: reportAny=false
 from __future__ import annotations
 
-from typing import Any
-
 from django import template
 from django.template.base import NodeList
 from django.template.base import Parser
@@ -11,11 +9,8 @@
 
 from django_bird._typing import TagBits
 from django_bird._typing import override
-from django_bird.components import Component
 from django_bird.components import components
 from django_bird.params import Param
-from django_bird.slots import DEFAULT_SLOT
-from django_bird.slots import Slots
 
 TAG = "bird"
 END_TAG = "endbird"
@@ -73,12 +68,11 @@ def __init__(
     def render(self, context: Context) -> str:
         component_name = self.get_component_name(context)
         component = components.get_component(component_name)
-        component_context = self.get_component_context_data(component, context)
-        bound_component = component.get_bound_component(attrs=self.attrs)
+        bound_component = component.get_bound_component(node=self)
 
         if self.isolated_context:
-            return bound_component.render(context.new(component_context))
-        with context.push(**component_context):
+            return bound_component.render(context.new())
+        else:
             return bound_component.render(context)
 
     def get_component_name(self, context: Context) -> str:
@@ -87,14 +81,3 @@ def get_component_name(self, context: Context) -> str:
         except template.VariableDoesNotExist:
             name = self.name
         return name
-
-    def get_component_context_data(
-        self, component: Component, context: Context
-    ) -> dict[str, Any]:
-        slots = Slots.collect(self.nodelist, context).render()
-        default_slot = slots.get(DEFAULT_SLOT) or context.get("slot")
-
-        return {
-            "slot": default_slot,
-            "slots": slots,
-        }

src/django_bird/templatetags/tags/bird.py

@@ -17,6 +17,8 @@
 TAG = "bird:slot"
 END_TAG = "endbird:slot"
 
+DEFAULT_SLOT = "default"
+
 
 def do_slot(parser: Parser, token: Token) -> SlotNode:
     bits = token.split_contents()
@@ -27,7 +29,7 @@ def do_slot(parser: Parser, token: Token) -> SlotNode:
 
 def parse_slot_name(bits: TagBits) -> str:
     if len(bits) == 1:
-        return "default"
+        return DEFAULT_SLOT
     elif len(bits) == 2:
         name = bits[1]
         if name.startswith("name="):

src/django_bird/templatetags/tags/slot.py

@@ -1374,11 +1374,11 @@ def test_parent_context_access(test_case, templates_dir, normalize_whitespace):
             ),
             template_content="""
                 {% bird button only %}
-                    {% bird:slot prefix %}{{ user.role }}{% endbird:slot %}
+                    {% bird:slot prefix %}{{ user.role|default:"User" }}{% endbird:slot %}
                 {% endbird %}
             """,
             template_context={"user": {"name": "John", "role": "Admin"}},
-            expected="<button>Admin Anonymous</button>",
+            expected="<button>User Anonymous</button>",
         ),
         TestComponentCase(
             description="Only flag with self-closing tag",

tests/templatetags/test_bird.py

@@ -36,10 +36,6 @@ def test_from_name_basic(self, templates_dir):
         assert comp.name == "button"
         assert isinstance(comp.template, DjangoTemplate)
 
-        bound = comp.get_bound_component([])
-
-        assert bound.render(Context({})) == "<button>Click me</button>"
-
     def test_from_name_with_assets(self, templates_dir):
         button = TestComponent(
             name="button", content="<button>Click me</button>"
@@ -109,10 +105,6 @@ def test_from_name_custom_component_dir(self, templates_dir, override_app_settin
         assert comp.name == "button"
         assert isinstance(comp.template, DjangoTemplate)
 
-        bound = comp.get_bound_component([])
-
-        assert bound.render(Context({})) == "<button>Click me</button>"
-
     def test_id_is_consistent(self, templates_dir):
         button = TestComponent(
             name="button", content="<button>Click me</button>"