[globals] Emit globals.set value lambda with declared global type

Pass the global's declared C++ type as the lambda return type so
TemplatableFn stores a direct function pointer instead of hitting the
deprecated converting trampoline when the value expression deduces to a
different type (e.g. an int literal or int-returning lambda assigned to
a float global).

esphome/components/globals/__init__.py

@@ -1,3 +1,4 @@
+from dataclasses import dataclass, field
 import hashlib
 
 from esphome import automation, codegen as cg, config_validation as cv
@@ -8,10 +9,11 @@ from esphome.const import (
     CONF_TYPE,
     CONF_VALUE,
 )
-from esphome.core import CoroPriority, coroutine_with_priority
+from esphome.core import CORE, CoroPriority, coroutine_with_priority
 from esphome.types import ConfigType
 
 CODEOWNERS = ["@esphome/core"]
+DOMAIN = "globals"
 globals_ns = cg.esphome_ns.namespace("globals")
 GlobalsComponent = globals_ns.class_("GlobalsComponent", cg.Component)
 RestoringGlobalsComponent = globals_ns.class_(
@@ -60,11 +62,25 @@ MULTI_CONF = True
 CONFIG_SCHEMA = _globals_schema
 
 
+@dataclass
+class GlobalsData:
+    # Map of global id -> user-declared C++ type string (e.g. 'float') so the
+    # globals.set action can emit lambdas with the matching return type.
+    types: dict = field(default_factory=dict)
+
+
+def _get_data() -> GlobalsData:
+    if DOMAIN not in CORE.data:
+        CORE.data[DOMAIN] = GlobalsData()
+    return CORE.data[DOMAIN]
+
+
 # Run with low priority so that namespaces are registered first
 @coroutine_with_priority(CoroPriority.LATE)
 async def to_code(config):
     type_ = cg.RawExpression(config[CONF_TYPE])
     restore = config[CONF_RESTORE_VALUE]
+    _get_data().types[config[CONF_ID]] = config[CONF_TYPE]
 
     # Special casing the strings to their own class with a different save/restore mechanism
     if str(type_) == "std::string" and restore:
@@ -108,8 +124,13 @@ async def globals_set_to_code(config, action_id, template_arg, args):
     full_id, paren = await cg.get_variable_with_full_id(config[CONF_ID])
     template_arg = cg.TemplateArguments(full_id.type, *template_arg)
     var = cg.new_Pvariable(action_id, template_arg, paren)
+    # Use the global's declared C++ type as the lambda return type so
+    # TemplatableFn stores a direct function pointer instead of going through
+    # the deprecated converting trampoline when the value expression deduces
+    # to a different type (e.g. int literal assigned to a float global).
+    value_type = cg.RawExpression(_get_data().types[config[CONF_ID]])
     templ = await cg.templatable(
-        config[CONF_VALUE], args, None, to_exp=cg.RawExpression, wrap_constant=True
+        config[CONF_VALUE], args, value_type, to_exp=cg.RawExpression
     )
     cg.add(var.set_value(templ))
     return var

tests/components/globals/common.yaml

@@ -4,6 +4,14 @@ esphome:
       - globals.set:
           id: glob_int
           value: "10"
+      # Set a float global with an integer literal - must emit the correct
+      # return type so TemplatableFn stores a direct function pointer.
+      - globals.set:
+          id: glob_float
+          value: "102"
+      - globals.set:
+          id: glob_float
+          value: !lambda "return 42;"
 
 globals:
   - id: glob_int