[lvgl] Use contextvars to improve lvgl scheduling (#19242)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

tests/component_tests/lvgl/config/keyboard_before_textarea_test.yaml

@@ -0,0 +1,28 @@
+esphome:
+  name: test-keyboard-before-textarea
+
+esp32:
+  board: lolin_c3_mini
+
+spi:
+  mosi_pin:
+    number: GPIO2
+    ignore_strapping_warning: true
+  clk_pin: GPIO1
+
+display:
+  - platform: mipi_spi
+    data_rate: 20MHz
+    model: st7735
+    cs_pin:
+      number: GPIO8
+      ignore_strapping_warning: true
+    dc_pin: GPIO3
+
+lvgl:
+  widgets:
+    - keyboard:
+        id: kb
+        textarea: ta
+    - textarea:
+        id: ta

tests/component_tests/lvgl/config/keyboard_update_textarea_test.yaml

@@ -0,0 +1,34 @@
+esphome:
+  name: test-keyboard-update-textarea
+  on_boot:
+    - lvgl.keyboard.update:
+        id: kb
+        textarea: ta2
+
+esp32:
+  board: lolin_c3_mini
+
+spi:
+  mosi_pin:
+    number: GPIO2
+    ignore_strapping_warning: true
+  clk_pin: GPIO1
+
+display:
+  - platform: mipi_spi
+    data_rate: 20MHz
+    model: st7735
+    cs_pin:
+      number: GPIO8
+      ignore_strapping_warning: true
+    dc_pin: GPIO3
+
+lvgl:
+  widgets:
+    - keyboard:
+        id: kb
+        textarea: ta1
+    - textarea:
+        id: ta1
+    - textarea:
+        id: ta2

tests/component_tests/lvgl/config/multi_instance_theme_test.yaml

@@ -0,0 +1,35 @@
+esphome:
+  name: test-multi-instance-theme
+
+host:
+  mac_address: "62:23:45:AF:B3:DD"
+
+display:
+  - platform: snapshot
+    id: sdl0
+    dimensions:
+      width: 100
+      height: 100
+  - platform: snapshot
+    id: sdl1
+    dimensions:
+      width: 100
+      height: 100
+
+lvgl:
+  - id: lvgl_0
+    displays: sdl0
+    widgets:
+      - label:
+          id: label_0
+          text: "First"
+
+  - id: lvgl_1
+    displays: sdl1
+    theme:
+      label:
+        bg_color: 0xFF0000
+    widgets:
+      - label:
+          id: label_1
+          text: "Second"

tests/component_tests/lvgl/test_keyboard_before_textarea.py

@@ -0,0 +1,47 @@
+"""Regression test: a keyboard: declared before its textarea: sibling must
+still get attached to it, and only after both widgets exist.
+
+attach_textareas() runs as a deferred pass, after every widget (across every
+LVGL instance) is created, so it must emit the attach call after the
+keyboard's own creation statement, not inline during widget creation.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from esphome.__main__ import generate_cpp_contents
+from esphome.config import read_config
+from esphome.core import CORE
+
+
+@pytest.fixture(scope="module")
+def main_cpp(request: pytest.FixtureRequest) -> str:
+    config_path = (
+        Path(request.fspath).parent / "config" / "keyboard_before_textarea_test.yaml"
+    )
+    original_path = CORE.config_path
+    try:
+        CORE.config_path = config_path
+        CORE.config = read_config({})
+        generate_cpp_contents(CORE.config)
+        return CORE.cpp_main_section
+    finally:
+        CORE.config_path = original_path
+        CORE.reset()
+
+
+def test_keyboard_and_textarea_are_created(main_cpp: str) -> None:
+    assert "lv_keyboard_create(" in main_cpp
+    assert "lv_textarea_create(" in main_cpp
+
+
+def test_attach_call_runs_after_keyboard_and_textarea_are_created(
+    main_cpp: str,
+) -> None:
+    attach_index = main_cpp.find("lv_keyboard_set_textarea(kb->obj, ta);")
+    assert attach_index != -1, "keyboard was never attached to its textarea"
+    assert attach_index > main_cpp.find("lv_keyboard_create(")
+    assert attach_index > main_cpp.find("lv_textarea_create(")

tests/component_tests/lvgl/test_keyboard_update_textarea.py

@@ -0,0 +1,33 @@
+"""Regression test: lvgl.keyboard.update must be able to change which
+textarea a keyboard is attached to.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from esphome.__main__ import generate_cpp_contents
+from esphome.config import read_config
+from esphome.core import CORE
+
+
+@pytest.fixture(scope="module")
+def main_cpp(request: pytest.FixtureRequest) -> str:
+    config_path = (
+        Path(request.fspath).parent / "config" / "keyboard_update_textarea_test.yaml"
+    )
+    original_path = CORE.config_path
+    try:
+        CORE.config_path = config_path
+        CORE.config = read_config({})
+        generate_cpp_contents(CORE.config)
+        return CORE.cpp_main_section
+    finally:
+        CORE.config_path = original_path
+        CORE.reset()
+
+
+def test_keyboard_update_changes_textarea(main_cpp: str) -> None:
+    assert "lv_keyboard_set_textarea(kb->obj, ta2);" in main_cpp

tests/component_tests/lvgl/test_list.py

@@ -286,7 +286,7 @@ def test_add_text_with_index_moves_before_firing_on_add(main_cpp: str) -> None:
 
 
 def test_add_button_with_checkable_flag(main_cpp: str) -> None:
-    assert "lv_obj_t *dyn_button_VAR_ = lv_btn_create(test_list);" in main_cpp
+    assert "lv_obj_t *dyn_button_VAR_ = lv_button_create(test_list);" in main_cpp
     assert (
         "lv_obj_add_flag(dyn_button_VAR_, (lv_obj_flag_t)(LV_OBJ_FLAG_CHECKABLE));"
         in main_cpp
@@ -310,7 +310,7 @@ def test_add_nested_hierarchy_with_compound_child(main_cpp: str) -> None:
     assert (
         "lv_obj_t *dyn_label_1_VAR_ = lv_label_create(dyn_obj_VAR_);\n"
         "            lv_obj_add_style(dyn_label_1_VAR_, _lv_theme_style_label_main_default, "
-        "(lv_state_t)(LV_PART_MAIN));\n"
+        "LV_PART_MAIN);\n"
         '            lv_label_set_text(dyn_label_1_VAR_, "Nested");'
     ) in main_cpp
 
@@ -321,7 +321,7 @@ def test_add_applies_theme_styles_to_dynamic_widget(main_cpp: str) -> None:
     """
     assert (
         "lv_obj_add_style(dyn_label_1_VAR_, _lv_theme_style_label_main_default, "
-        "(lv_state_t)(LV_PART_MAIN));"
+        "LV_PART_MAIN);"
     ) in main_cpp
     assert "LvDropdownType *dyn_dropdown_1_VAR_ = new LvDropdownType();" in main_cpp
     assert "lv_dropdown_create(dyn_obj_VAR_)" in main_cpp
@@ -343,7 +343,7 @@ def test_add_nested_same_type_child_does_not_shadow_parent(main_cpp: str) -> Non
     assert (
         "lv_obj_t *dyn_label_2_VAR_ = lv_label_create(dyn_obj_1_VAR_);\n"
         "                lv_obj_add_style(dyn_label_2_VAR_, _lv_theme_style_label_main_default, "
-        "(lv_state_t)(LV_PART_MAIN));\n"
+        "LV_PART_MAIN);\n"
         '                lv_label_set_text(dyn_label_2_VAR_, "Grandchild");'
     ) in main_cpp
 

tests/component_tests/lvgl/test_list_on_add_lvgl_action.py

@@ -1,16 +1,4 @@
-"""Regression test: on_add:/on_remove: containing an lvgl action must not deadlock.
-
-ListType.to_code() used to build the on_add/on_remove automations directly, during
-widget creation. Every lvgl action's to_code awaits wait_for_widgets(), which only
-resolves once *all* widgets - including the list itself - have finished being
-created. Building an automation containing an lvgl action from inside that same
-widget-creation walk therefore could never complete: codegen deadlocked with
-"Circular dependency detected!". Fixed by deferring the actual build_automation()
-call to finish_list_triggers(), run after set_widgets_completed(True) - and,
-critically, before generate_triggers(), which is what processes other widgets'
-on_click etc. automations that might reference this list (e.g. via lvgl.list.add),
-and which therefore need the list's own on_add/on_remove triggers to already exist.
-"""
+"""Regression test: on_add:/on_remove: containing an lvgl action must not deadlock."""
 
 from __future__ import annotations
 

tests/component_tests/lvgl/test_multi_instance_theme.py

@@ -0,0 +1,44 @@
+"""Regression test: a widget's theme style must be attached regardless of
+which LVGL instance declares theme: and which instance's widgets are built
+first.
+
+theme_to_code() runs once per LVGL instance, interleaved with that instance's
+own add_widgets(). A widget built by an earlier instance, before any instance
+has declared theming for its type, must still pick up a later instance's
+theme: declaration for that type - including on the later instance's own
+widgets, which get_widget_theme_styles()'s memoisation can poison too.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from esphome.__main__ import generate_cpp_contents
+from esphome.config import read_config
+from esphome.core import CORE
+
+
+@pytest.fixture(scope="module")
+def main_cpp(request: pytest.FixtureRequest) -> str:
+    config_path = (
+        Path(request.fspath).parent / "config" / "multi_instance_theme_test.yaml"
+    )
+    original_path = CORE.config_path
+    try:
+        CORE.config_path = config_path
+        CORE.config = read_config({})
+        generate_cpp_contents(CORE.config)
+        return CORE.cpp_main_section
+    finally:
+        CORE.config_path = original_path
+        CORE.reset()
+
+
+def test_earlier_instance_widget_is_themed(main_cpp: str) -> None:
+    assert "lv_obj_add_style(label_0, _lv_theme_style_label_main_default," in main_cpp
+
+
+def test_later_instance_widget_is_themed(main_cpp: str) -> None:
+    assert "lv_obj_add_style(label_1, _lv_theme_style_label_main_default," in main_cpp