From 5a146ab6b75958fd855ccbbe965a95fe7e1f15ce Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Wed, 29 Apr 2026 14:20:15 -0500
Subject: [PATCH] [valve] Fold ControlAction fields into a single stateless
 lambda (#16123)

---
 esphome/components/valve/__init__.py  | 50 ++++++++++++++++++++-------
 esphome/components/valve/automation.h | 17 ++++-----
 2 files changed, 46 insertions(+), 21 deletions(-)

diff --git a/esphome/components/valve/__init__.py b/esphome/components/valve/__init__.py
index a6808c9da7..7377aea1ed 100644
--- a/esphome/components/valve/__init__.py
+++ b/esphome/components/valve/__init__.py
@@ -21,14 +21,14 @@ from esphome.const import (
     DEVICE_CLASS_GAS,
     DEVICE_CLASS_WATER,
 )
-from esphome.core import CORE, CoroPriority, coroutine_with_priority
+from esphome.core import CORE, CoroPriority, Lambda, coroutine_with_priority
 from esphome.core.entity_helpers import (
     entity_duplicate_validator,
     queue_entity_register,
     setup_device_class,
     setup_entity,
 )
-from esphome.cpp_generator import MockObjClass
+from esphome.cpp_generator import LambdaExpression, MockObjClass
 
 IS_PLATFORM_COMPONENT = True
 
@@ -43,6 +43,7 @@ DEVICE_CLASSES = [
 valve_ns = cg.esphome_ns.namespace("valve")
 
 Valve = valve_ns.class_("Valve", cg.EntityBase)
+ValveCall = valve_ns.class_("ValveCall")
 
 VALVE_OPEN = valve_ns.VALVE_OPEN
 VALVE_CLOSED = valve_ns.VALVE_CLOSED
@@ -228,17 +229,40 @@ VALVE_CONTROL_ACTION_SCHEMA = cv.Schema(
 )
 async def valve_control_to_code(config, action_id, template_arg, args):
     paren = await cg.get_variable(config[CONF_ID])
-    var = cg.new_Pvariable(action_id, template_arg, paren)
-    if stop_config := config.get(CONF_STOP):
-        template_ = await cg.templatable(stop_config, args, cg.bool_)
-        cg.add(var.set_stop(template_))
-    if state_config := config.get(CONF_STATE):
-        template_ = await cg.templatable(state_config, args, cg.float_)
-        cg.add(var.set_position(template_))
-    if (position_config := config.get(CONF_POSITION)) is not None:
-        template_ = await cg.templatable(position_config, args, cg.float_)
-        cg.add(var.set_position(template_))
-    return var
+
+    # All configured fields are folded into a single stateless lambda whose
+    # constants live in flash; the action stores only a function pointer.
+    # CONF_STATE and CONF_POSITION are cv.Exclusive in the schema, so at most
+    # one is present and both dispatch to set_position.
+    FIELDS = (
+        (CONF_STOP, "set_stop", cg.bool_),
+        (CONF_STATE, "set_position", cg.float_),
+        (CONF_POSITION, "set_position", cg.float_),
+    )
+
+    fwd_args = ", ".join(name for _, name in args)
+    body_lines: list[str] = []
+    for conf_key, setter, type_ in FIELDS:
+        if (value := config.get(conf_key)) is None:
+            continue
+        if isinstance(value, Lambda):
+            inner = await cg.process_lambda(value, args, return_type=type_)
+            body_lines.append(f"call.{setter}(({inner})({fwd_args}));")
+        else:
+            body_lines.append(f"call.{setter}({cg.safe_exp(value)});")
+
+    # Match ControlAction::ApplyFn signature: const Ts &... for trigger args.
+    apply_args = [
+        (ValveCall.operator("ref"), "call"),
+        *((t.operator("const").operator("ref"), n) for t, n in args),
+    ]
+    apply_lambda = LambdaExpression(
+        ["\n".join(body_lines)],
+        apply_args,
+        capture="",
+        return_type=cg.void,
+    )
+    return cg.new_Pvariable(action_id, template_arg, paren, apply_lambda)
 
 
 @coroutine_with_priority(CoroPriority.CORE)
diff --git a/esphome/components/valve/automation.h b/esphome/components/valve/automation.h
index a064f375f7..ae9ac0db76 100644
--- a/esphome/components/valve/automation.h
+++ b/esphome/components/valve/automation.h
@@ -47,24 +47,25 @@ template<typename... Ts> class ToggleAction : public Action<Ts...> {
   Valve *valve_;
 };
 
+// All configured fields are baked into a single stateless lambda whose
+// constants live in flash. The action only stores one function pointer
+// plus one parent pointer, regardless of how many fields the user set.
+// Trigger args are forwarded to the apply function so user lambdas
+// (e.g. `position: !lambda "return x;"`) keep working.
 template<typename... Ts> class ControlAction : public Action<Ts...> {
  public:
-  explicit ControlAction(Valve *valve) : valve_(valve) {}
-
-  TEMPLATABLE_VALUE(bool, stop)
-  TEMPLATABLE_VALUE(float, position)
+  using ApplyFn = void (*)(ValveCall &, const Ts &...);
+  ControlAction(Valve *valve, ApplyFn apply) : valve_(valve), apply_(apply) {}
 
   void play(const Ts &...x) override {
     auto call = this->valve_->make_call();
-    if (this->stop_.has_value())
-      call.set_stop(this->stop_.value(x...));
-    if (this->position_.has_value())
-      call.set_position(this->position_.value(x...));
+    this->apply_(call, x...);
     call.perform();
   }
 
  protected:
   Valve *valve_;
+  ApplyFn apply_;
 };
 
 template<typename... Ts> class ValveIsOpenCondition : public Condition<Ts...> {