deprecate hotswap

Author: rmorshea

docs/source/about/changelog.rst

@@ -23,14 +23,17 @@ more info, see the :ref:`Contributor Guide <Creating a Changelog Entry>`.
 Unreleased
 ----------
 
-No changes.
+**Deprecated**
+
+- :pull:`876` - ``idom.widgets.hotswap``. The function has no clear uses outside of some
+  internal applications. For this reason it has been deprecated.
 
 
 v0.43.0
 -------
 :octicon:`milestone` *released on 2023-01-09*
 
-**Removed**
+**Deprecated**
 
 - :pull:`870` - ``ComponentType.should_render()``. This method was implemented based on
   reading the React/Preact source code. As it turns out though it seems like it's mostly

pyproject.toml

@@ -52,4 +52,4 @@ max-complexity = 18
 select = ["B", "C", "E", "F", "W", "T4", "B9", "N", "ROH"]
 exclude = ["**/node_modules/*", ".eggs/*", ".tox/*"]
 # -- flake8-tidy-imports --
-ban-relative-imports = "parents"
+ban-relative-imports = "true"

scripts/one_example.py

@@ -32,7 +32,7 @@ def watch_for_change():
 def main():
     ex_name = _example_name_input()
 
-    mount, component = _hotswap(update_on_change=True)
+    mount, component = _hotswap()
 
     def update_component():
         print(f"Loading example: {ex_name!r}")

src/idom/__init__.py

@@ -1,10 +1,10 @@
-from . import backend, config, html, logging, sample, svg, types, web
-from .backend.hooks import use_connection, use_location, use_scope
-from .backend.utils import run
-from .core import hooks
-from .core.component import component
-from .core.events import event
-from .core.hooks import (
+from idom import backend, config, html, logging, sample, svg, types, web, widgets
+from idom.backend.hooks import use_connection, use_location, use_scope
+from idom.backend.utils import run
+from idom.core import hooks
+from idom.core.component import component
+from idom.core.events import event
+from idom.core.hooks import (
     create_context,
     use_callback,
     use_context,
@@ -15,11 +15,10 @@
     use_ref,
     use_state,
 )
-from .core.layout import Layout
-from .core.serve import Stop
-from .core.vdom import vdom
-from .utils import Ref, html_to_vdom, vdom_to_html
-from .widgets import _hotswap
+from idom.core.layout import Layout
+from idom.core.serve import Stop
+from idom.core.vdom import vdom
+from idom.utils import Ref, html_to_vdom, vdom_to_html
 
 
 __author__ = "idom-team"
@@ -32,7 +31,6 @@
     "create_context",
     "event",
     "hooks",
-    "_hotswap",
     "html_to_vdom",
     "html",
     "Layout",
@@ -57,4 +55,5 @@
     "vdom_to_html",
     "vdom",
     "web",
+    "widgets",
 ]

src/idom/testing/backend.py

@@ -7,11 +7,11 @@
 from typing import Any, Callable, Optional, Tuple, Type, Union
 from urllib.parse import urlencode, urlunparse
 
-from idom import component, use_effect, use_state
 from idom.backend import default as default_server
 from idom.backend.types import BackendImplementation
 from idom.backend.utils import find_available_port
-from idom.core.hooks import use_callback
+from idom.core.component import component
+from idom.core.hooks import use_callback, use_effect, use_state
 from idom.core.types import ComponentConstructor
 from idom.utils import Ref
 
@@ -190,28 +190,39 @@ def DivTwo(self):
     """
     constructor_ref: Ref[Callable[[], Any]] = Ref(lambda: None)
 
-    set_constructor_callbacks: set[Callable[[Callable[[], Any]], None]] = set()
+    if update_on_change:
+        set_constructor_callbacks: set[Callable[[Callable[[], Any]], None]] = set()
 
-    @component
-    def HotSwap() -> Any:
-        # new displays will adopt the latest constructor and arguments
-        constructor, _set_constructor = use_state(lambda: constructor_ref.current)
-        set_constructor = use_callback(lambda new: _set_constructor(lambda _: new))
+        @component
+        def HotSwap() -> Any:
+            # new displays will adopt the latest constructor and arguments
+            constructor, _set_constructor = use_state(lambda: constructor_ref.current)
+            set_constructor = use_callback(lambda new: _set_constructor(lambda _: new))
 
-        def add_callback() -> Callable[[], None]:
-            set_constructor_callbacks.add(set_constructor)
-            return lambda: set_constructor_callbacks.remove(set_constructor)
+            def add_callback() -> Callable[[], None]:
+                set_constructor_callbacks.add(set_constructor)
+                return lambda: set_constructor_callbacks.remove(set_constructor)
 
-        use_effect(add_callback)
+            use_effect(add_callback)
 
-        return constructor()
+            return constructor()
 
-    def swap(constructor: Callable[[], Any] | None) -> None:
-        constructor = constructor_ref.current = constructor or (lambda: None)
+        def swap(constructor: Callable[[], Any] | None) -> None:
+            constructor = constructor_ref.current = constructor or (lambda: None)
 
-        for set_constructor in set_constructor_callbacks:
-            set_constructor(constructor)
+            for set_constructor in set_constructor_callbacks:
+                set_constructor(constructor)
 
-        return None
+            return None
+
+    else:
+
+        @component
+        def HotSwap() -> Any:
+            return constructor_ref.current()
+
+        def swap(constructor: Callable[[], Any] | None) -> None:
+            constructor_ref.current = constructor or (lambda: None)
+            return None
 
     return swap, HotSwap

src/idom/widgets.py

@@ -1,30 +1,16 @@
 from __future__ import annotations
 
 from base64 import b64encode
-from typing import (
-    Any,
-    Callable,
-    Dict,
-    List,
-    Optional,
-    Sequence,
-    Set,
-    Tuple,
-    TypeVar,
-    Union,
-)
+from typing import Any, Callable, Dict, List, Optional, Sequence, Tuple, TypeVar, Union
 from warnings import warn
 
 from typing_extensions import Protocol
 
 import idom
 
 from . import html
-from .core import hooks
-from .core.component import component
 from .core.types import ComponentConstructor, VdomDict
 from .testing.backend import _hotswap, _MountFunc
-from .utils import Ref
 
 
 def image(
@@ -109,7 +95,9 @@ def __call__(self, value: str) -> _CastTo:
         ...
 
 
-def hotswap(update_on_change: bool = False) -> Tuple[_MountFunc, ComponentConstructor]:
+def hotswap(
+    update_on_change: bool = False,
+) -> Tuple[_MountFunc, ComponentConstructor]:  # pragma: no cover
     warn(
         "The 'hotswap' function is deprecated and will be removed in a future release",
         DeprecationWarning,

tests/test_testing.py

@@ -3,10 +3,12 @@
 
 import pytest
 
-from idom import testing
+from idom import Ref, component, html, testing
 from idom.backend import starlette as starlette_implementation
 from idom.logging import ROOT_LOGGER
 from idom.sample import SampleApp as SampleApp
+from idom.testing.backend import _hotswap
+from idom.testing.display import DisplayFixture
 
 
 def test_assert_idom_logged_does_not_supress_errors():
@@ -162,3 +164,48 @@ def test_list_logged_excptions():
 
         logged_errors = testing.logs.list_logged_exceptions(records)
         assert logged_errors == [the_error]
+
+
+async def test_hostwap_update_on_change(display: DisplayFixture):
+    """Ensure shared hotswapping works
+
+    This basically means that previously rendered views of a hotswap component get updated
+    when a new view is mounted, not just the next time it is re-displayed
+
+    In this test we construct a scenario where clicking a button will cause a pre-existing
+    hotswap component to be updated
+    """
+
+    def make_next_count_constructor(count):
+        """We need to construct a new function so they're different when we set_state"""
+
+        def constructor():
+            count.current += 1
+            return html.div({"id": f"hotswap-{count.current}"}, count.current)
+
+        return constructor
+
+    @component
+    def ButtonSwapsDivs():
+        count = Ref(0)
+
+        async def on_click(event):
+            mount(make_next_count_constructor(count))
+
+        incr = html.button({"onClick": on_click, "id": "incr-button"}, "incr")
+
+        mount, make_hostswap = _hotswap(update_on_change=True)
+        mount(make_next_count_constructor(count))
+        hotswap_view = make_hostswap()
+
+        return html.div(incr, hotswap_view)
+
+    await display.show(ButtonSwapsDivs)
+
+    client_incr_button = await display.page.wait_for_selector("#incr-button")
+
+    await display.page.wait_for_selector("#hotswap-1")
+    await client_incr_button.click()
+    await display.page.wait_for_selector("#hotswap-2")
+    await client_incr_button.click()
+    await display.page.wait_for_selector("#hotswap-3")