Change set_state comparison method (#1256)

Author: Archmonger

docs/source/about/changelog.rst

@@ -20,6 +20,7 @@ Unreleased
 - :pull:`1251` - Substitute client-side usage of ``react`` with ``preact``.
 - :pull:`1239` - Script elements no longer support behaving like effects. They now strictly behave like plain HTML script elements.
 - :pull:`1255` - The ``reactpy.html`` module has been modified to allow for auto-creation of any HTML nodes. For example, you can create a ``<data-table>`` element by calling ``html.data_table()``.
+- :pull:`1256` - Change ``set_state`` comparison method to check equality with ``==`` more consistently.
 
 **Removed**
 
@@ -34,6 +35,7 @@ Unreleased
 
 v1.1.0
 ------
+:octicon:`milestone` *released on 2024-11-24*
 
 **Fixed**
 
@@ -69,6 +71,7 @@ v1.1.0
 
 v1.0.2
 ------
+:octicon:`milestone` *released on 2023-07-03*
 
 **Fixed**
 
@@ -77,6 +80,7 @@ v1.0.2
 
 v1.0.1
 ------
+:octicon:`milestone` *released on 2023-06-16*
 
 **Changed**
 

src/reactpy/core/hooks.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import asyncio
+import contextlib
 from collections.abc import Coroutine, MutableMapping, Sequence
 from logging import getLogger
 from types import FunctionType
@@ -517,18 +518,30 @@ def strictly_equal(x: Any, y: Any) -> bool:
     - ``bytearray``
     - ``memoryview``
     """
-    return x is y or (type(x) in _NUMERIC_TEXT_BINARY_TYPES and x == y)
-
-
-_NUMERIC_TEXT_BINARY_TYPES = {
-    # numeric
-    int,
-    float,
-    complex,
-    # text
-    str,
-    # binary types
-    bytes,
-    bytearray,
-    memoryview,
-}
+    # Return early if the objects are not the same type
+    if type(x) is not type(y):
+        return False
+
+    # Compare the source code of lambda and local functions
+    if (
+        hasattr(x, "__qualname__")
+        and ("<lambda>" in x.__qualname__ or "<locals>" in x.__qualname__)
+        and hasattr(x, "__code__")
+    ):
+        if x.__qualname__ != y.__qualname__:
+            return False
+
+        return all(
+            getattr(x.__code__, attr) == getattr(y.__code__, attr)
+            for attr in dir(x.__code__)
+            if attr.startswith("co_")
+            and attr not in {"co_positions", "co_linetable", "co_lines"}
+        )
+
+    # Check via the `==` operator if possible
+    if hasattr(x, "__eq__"):
+        with contextlib.suppress(Exception):
+            return x == y  # type: ignore
+
+    # Fallback to identity check
+    return x is y

tests/test_core/test_hooks.py

@@ -159,7 +159,7 @@ def Counter():
             await layout.render()
 
 
-async def test_set_state_checks_identity_not_equality(display: DisplayFixture):
+async def test_set_state_checks_equality_not_identity(display: DisplayFixture):
     r_1 = reactpy.Ref("value")
     r_2 = reactpy.Ref("value")
 
@@ -219,12 +219,12 @@ def TestComponent():
     await client_r_2_button.click()
 
     await poll_event_count.until_equals(2)
-    await poll_render_count.until_equals(2)
+    await poll_render_count.until_equals(1)
 
     await client_r_2_button.click()
 
     await poll_event_count.until_equals(3)
-    await poll_render_count.until_equals(2)
+    await poll_render_count.until_equals(1)
 
 
 async def test_simple_input_with_use_state(display: DisplayFixture):
@@ -1172,6 +1172,28 @@ def test_strictly_equal(x, y, result):
     assert strictly_equal(x, y) is result
 
 
+def test_strictly_equal_named_closures():
+    assert strictly_equal(lambda: "text", lambda: "text") is True
+    assert strictly_equal(lambda: "text", lambda: "not-text") is False
+
+    def x():
+        return "text"
+
+    def y():
+        return "not-text"
+
+    def generator():
+        def z():
+            return "text"
+
+        return z
+
+    assert strictly_equal(x, x) is True
+    assert strictly_equal(x, y) is False
+    assert strictly_equal(x, generator()) is False
+    assert strictly_equal(generator(), generator()) is True
+
+
 STRICT_EQUALITY_VALUE_CONSTRUCTORS = [
     lambda: "string-text",
     lambda: b"byte-text",

tests/test_testing.py

@@ -173,7 +173,7 @@ def test_list_logged_excptions():
         assert logged_errors == [the_error]
 
 
-async def test_hostwap_update_on_change(display: DisplayFixture):
+async def test_hotswap_update_on_change(display: DisplayFixture):
     """Ensure shared hotswapping works
 
     This basically means that previously rendered views of a hotswap component get updated
@@ -183,34 +183,39 @@ async def test_hostwap_update_on_change(display: DisplayFixture):
     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 hotswap_1():
+        return html.div({"id": "hotswap-1"}, 1)
 
-        def constructor():
-            count.current += 1
-            return html.div({"id": f"hotswap-{count.current}"}, count.current)
+    def hotswap_2():
+        return html.div({"id": "hotswap-2"}, 2)
 
-        return constructor
+    def hotswap_3():
+        return html.div({"id": "hotswap-3"}, 3)
 
     @component
     def ButtonSwapsDivs():
         count = Ref(0)
+        mount, hostswap = _hotswap(update_on_change=True)
 
         async def on_click(event):
-            mount(make_next_count_constructor(count))
-
-        incr = html.button({"on_click": 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)
+            count.set_current(count.current + 1)
+            if count.current == 1:
+                mount(hotswap_1)
+            if count.current == 2:
+                mount(hotswap_2)
+            if count.current == 3:
+                mount(hotswap_3)
+
+        return html.div(
+            html.button({"on_click": on_click, "id": "incr-button"}, "incr"),
+            hostswap(),
+        )
 
     await display.show(ButtonSwapsDivs)
 
     client_incr_button = await display.page.wait_for_selector("#incr-button")
 
+    await client_incr_button.click()
     await display.page.wait_for_selector("#hotswap-1")
     await client_incr_button.click()
     await display.page.wait_for_selector("#hotswap-2")