globals is special

esphome/cpp_generator.py

@@ -600,7 +600,11 @@ def Pvariable(id_: ID, rhs: SafeExpType, type_: "MockObj" = None) -> "MockObj":
         )
         # Extract args from the CallExpression and rebuild as placement new
         call_expr = rhs.base  # CallExpression("new Type", args...)
-        placement_new = CallExpression(f"new({id_.id}) {the_type}", *call_expr.args)
+        placement_args: list[Expression] = []
+        if call_expr.template_args is not None:
+            placement_args.append(call_expr.template_args)
+        placement_args.extend(call_expr.args)
+        placement_new = CallExpression(f"new({id_.id}) {the_type}", *placement_args)
         CORE.add(ExpressionStatement(placement_new))
     else:
         decl = VariableDeclarationExpression(id_.type, "*", id_, static=True)

tests/component_tests/globals/config/globals_test.yaml

@@ -0,0 +1,16 @@
+esphome:
+  name: test
+
+esp32:
+  board: esp32dev
+
+globals:
+  - id: my_global_int
+    type: int
+    initial_value: "42"
+  - id: my_global_float
+    type: float
+    initial_value: "1.5"
+  - id: my_global_bool
+    type: bool
+    initial_value: "true"

tests/component_tests/globals/test_globals.py

@@ -0,0 +1,27 @@
+"""Tests for the globals component."""
+
+from __future__ import annotations
+
+from collections.abc import Callable
+from pathlib import Path
+
+
+def test_globals_placement_new_with_template_args(
+    generate_main: Callable[[str | Path], str],
+    component_config_path: Callable[[str], Path],
+) -> None:
+    """Test that globals uses placement new with template arguments preserved."""
+    main_cpp = generate_main(component_config_path("globals_test.yaml"))
+
+    # Globals uses Pvariable with Type.new(template_args, initial_value)
+    # which exercises the template_args preservation in placement new.
+    assert "static globals::GlobalsComponent<int> *const my_global_int" in main_cpp
+    assert "PlacementStorage<globals::GlobalsComponent<int>>" in main_cpp
+    assert "new(my_global_int) globals::GlobalsComponent<int>" in main_cpp
+
+    # Verify initial value is passed as constructor arg
+    assert "42" in main_cpp
+
+    # Check other globals are also generated
+    assert "PlacementStorage<globals::GlobalsComponent<float>>" in main_cpp
+    assert "PlacementStorage<globals::GlobalsComponent<bool>>" in main_cpp