[lvgl] Fix nested lambdas in automations unable to access parameters (#11583)

Co-authored-by: clydebarrow <2366188+clydebarrow@users.noreply.github.com>

esphome/components/lvgl/defines.py

@@ -5,6 +5,7 @@ Constants already defined in esphome.const are not duplicated here and must be i
 """
 
 import logging
+from typing import TYPE_CHECKING, Any
 
 from esphome import codegen as cg, config_validation as cv
 from esphome.const import CONF_ITEMS
@@ -12,6 +13,7 @@ from esphome.core import ID, Lambda
 from esphome.cpp_generator import LambdaExpression, MockObj
 from esphome.cpp_types import uint32
 from esphome.schema_extractors import SCHEMA_EXTRACT, schema_extractor
+from esphome.types import Expression, SafeExpType
 
 from .helpers import requires_component
 
@@ -42,7 +44,13 @@ def static_cast(type, value):
 def call_lambda(lamb: LambdaExpression):
     expr = lamb.content.strip()
     if expr.startswith("return") and expr.endswith(";"):
-        return expr[6:][:-1].strip()
+        return expr[6:-1].strip()
+    # If lambda has parameters, call it with those parameter names
+    # Parameter names come from hardcoded component code (like "x", "it", "event")
+    # not from user input, so they're safe to use directly
+    if lamb.parameters and lamb.parameters.parameters:
+        param_names = ", ".join(str(param.id) for param in lamb.parameters.parameters)
+        return f"{lamb}({param_names})"
     return f"{lamb}()"
 
 
@@ -65,10 +73,20 @@ class LValidator:
             return cv.returning_lambda(value)
         return self.validator(value)
 
-    async def process(self, value, args=()):
+    async def process(
+        self, value: Any, args: list[tuple[SafeExpType, str]] | None = None
+    ) -> Expression:
         if value is None:
             return None
         if isinstance(value, Lambda):
+            # Local import to avoid circular import
+            from .lvcode import CodeContext, LambdaContext
+
+            if TYPE_CHECKING:
+                # CodeContext does not have get_automation_parameters
+                # so we need to assert the type here
+                assert isinstance(CodeContext.code_context, LambdaContext)
+            args = args or CodeContext.code_context.get_automation_parameters()
             return cg.RawExpression(
                 call_lambda(
                     await cg.process_lambda(value, args, return_type=self.rtype)

esphome/components/lvgl/lv_validation.py

@@ -1,3 +1,5 @@
+from typing import TYPE_CHECKING, Any
+
 import esphome.codegen as cg
 from esphome.components import image
 from esphome.components.color import CONF_HEX, ColorStruct, from_rgbw
@@ -17,6 +19,7 @@ from esphome.cpp_generator import MockObj
 from esphome.cpp_types import ESPTime, int32, uint32
 from esphome.helpers import cpp_string_escape
 from esphome.schema_extractors import SCHEMA_EXTRACT, schema_extractor
+from esphome.types import Expression, SafeExpType
 
 from . import types as ty
 from .defines import (
@@ -388,11 +391,23 @@ class TextValidator(LValidator):
             return value
         return super().__call__(value)
 
-    async def process(self, value, args=()):
+    async def process(
+        self, value: Any, args: list[tuple[SafeExpType, str]] | None = None
+    ) -> Expression:
+        # Local import to avoid circular import at module level
+
+        from .lvcode import CodeContext, LambdaContext
+
+        if TYPE_CHECKING:
+            # CodeContext does not have get_automation_parameters
+            # so we need to assert the type here
+            assert isinstance(CodeContext.code_context, LambdaContext)
+        args = args or CodeContext.code_context.get_automation_parameters()
+
         if isinstance(value, dict):
             if format_str := value.get(CONF_FORMAT):
-                args = [str(x) for x in value[CONF_ARGS]]
+                str_args = [str(x) for x in value[CONF_ARGS]]
-                arg_expr = cg.RawExpression(",".join(args))
+                arg_expr = cg.RawExpression(",".join(str_args))
                 format_str = cpp_string_escape(format_str)
                 return literal(f"str_sprintf({format_str}, {arg_expr}).c_str()")
             if time_format := value.get(CONF_TIME_FORMAT):

esphome/components/lvgl/lvcode.py

@@ -164,6 +164,9 @@ class LambdaContext(CodeContext):
             code_text.append(text)
         return code_text
 
+    def get_automation_parameters(self) -> list[tuple[SafeExpType, str]]:
+        return self.parameters
+
     async def __aenter__(self):
         await super().__aenter__()
         add_line_marks(self.where)
@@ -178,9 +181,8 @@ class LvContext(LambdaContext):
 
     added_lambda_count = 0
 
-    def __init__(self, args=None):
+    def __init__(self):
-        self.args = args or LVGL_COMP_ARG
+        super().__init__(parameters=LVGL_COMP_ARG)
-        super().__init__(parameters=self.args)
 
     async def __aexit__(self, exc_type, exc_val, exc_tb):
         await super().__aexit__(exc_type, exc_val, exc_tb)
@@ -189,6 +191,11 @@ class LvContext(LambdaContext):
         cg.add(expression)
         return expression
 
+    def get_automation_parameters(self) -> list[tuple[SafeExpType, str]]:
+        # When generating automations, we don't want the `lv_component` parameter to be passed
+        # to the lambda.
+        return []
+
     def __call__(self, *args):
         return self.add(*args)
 

esphome/components/lvgl/sensor/__init__.py

@@ -5,7 +5,6 @@ from ..defines import CONF_WIDGET
 from ..lvcode import (
     API_EVENT,
     EVENT_ARG,
-    LVGL_COMP_ARG,
     UPDATE_EVENT,
     LambdaContext,
     LvContext,
@@ -30,7 +29,7 @@ async def to_code(config):
     await wait_for_widgets()
     async with LambdaContext(EVENT_ARG) as lamb:
         lv_add(sensor.publish_state(widget.get_value()))
-    async with LvContext(LVGL_COMP_ARG):
+    async with LvContext():
         lv_add(
             lvgl_static.add_event_cb(
                 widget.obj,

tests/components/lvgl/common.yaml

@@ -52,6 +52,19 @@ number:
     widget: spinbox_id
     id: lvgl_spinbox_number
     name: LVGL Spinbox Number
+  - platform: template
+    id: test_brightness
+    name: "Test Brightness"
+    min_value: 0
+    max_value: 255
+    step: 1
+    optimistic: true
+    # Test lambda in automation accessing x parameter directly
+    # This is a real-world pattern from user configs
+    on_value:
+      - lambda: !lambda |-
+          // Direct use of x parameter in automation
+          ESP_LOGD("test", "Brightness: %.0f", x);
 
 light:
   - platform: lvgl
@@ -110,3 +123,21 @@ text:
     platform: lvgl
     widget: hello_label
     mode: text
+
+text_sensor:
+  - platform: template
+    id: test_text_sensor
+    name: "Test Text Sensor"
+    # Test nested lambdas in LVGL actions can access automation parameters
+    on_value:
+      - lvgl.label.update:
+          id: hello_label
+          text: !lambda return x.c_str();
+      - lvgl.label.update:
+          id: hello_label
+          text: !lambda |-
+            // Test complex lambda with conditionals accessing x parameter
+            if (x == "*") {
+              return "WILDCARD";
+            }
+            return x.c_str();

tests/components/lvgl/lvgl-package.yaml

@@ -257,7 +257,30 @@ lvgl:
             text: "Hello shiny day"
             text_color: 0xFFFFFF
             align: bottom_mid
+        - label:
+            id: setup_lambda_label
+            # Test lambda in widget property during setup (LvContext)
+            # Should NOT receive lv_component parameter
+            text: !lambda |-
+              char buf[32];
+              snprintf(buf, sizeof(buf), "Setup: %d", 42);
+              return std::string(buf);
+            align: top_mid
             text_font: space16
+        - label:
+            id: chip_info_label
+            # Test complex setup lambda (real-world pattern)
+            # Should NOT receive lv_component parameter
+            text: !lambda |-
+              // Test conditional compilation and string formatting
+              char buf[64];
+              #ifdef USE_ESP_IDF
+              snprintf(buf, sizeof(buf), "IDF: v%d.%d", ESP_IDF_VERSION_MAJOR, ESP_IDF_VERSION_MINOR);
+              #else
+              snprintf(buf, sizeof(buf), "Arduino");
+              #endif
+              return std::string(buf);
+            align: top_left
         - obj:
             align: center
             arc_opa: COVER