From 476ec16a3d178ddf419b8201f45c6f6e6610b78a Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 23 Aug 2026 18:58:48 -0500
Subject: [PATCH] Split the AS and ASPP source kinds to match SCons

---
 esphome/platformio/library.py               | 13 +++++++------
 tests/unit_tests/test_platformio_library.py |  8 ++++----
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/esphome/platformio/library.py b/esphome/platformio/library.py
index 3cee9684e7..521337ff84 100644
--- a/esphome/platformio/library.py
+++ b/esphome/platformio/library.py
@@ -55,8 +55,9 @@ DEFAULT_BUILD_SRC_DIRS = "src"
 DEFAULT_BUILD_INCLUDE_DIR = "include"
 DEFAULT_BUILD_FLAGS = []
 # Suffix -> compiler kind (PlatformIO's CSUFFIXES/CXXSUFFIXES/ASSUFFIXES);
-# "asm" merges SCons's AS and ASPP sets. Per CXXSUFFIXES .C/.C++ are C++
-# here, even where SCons demotes .C on case-insensitive filesystems.
+# "aspp" is SCons's preprocessed-assembly set, "asm" its plain-assembler
+# set (no preprocessor, defines, or includes). Per CXXSUFFIXES .C/.C++ are
+# C++ here, even where SCons demotes .C on case-insensitive filesystems.
 SOURCE_KIND_FOR_SUFFIX: dict[str, str] = {
     ".c": "c",
     ".cpp": "cxx",
@@ -65,10 +66,10 @@ SOURCE_KIND_FOR_SUFFIX: dict[str, str] = {
     ".c++": "cxx",
     ".C": "cxx",
     ".C++": "cxx",
-    ".S": "asm",
-    ".spp": "asm",
-    ".SPP": "asm",
-    ".sx": "asm",
+    ".S": "aspp",
+    ".spp": "aspp",
+    ".SPP": "aspp",
+    ".sx": "aspp",
     ".s": "asm",
     ".asm": "asm",
     ".ASM": "asm",
diff --git a/tests/unit_tests/test_platformio_library.py b/tests/unit_tests/test_platformio_library.py
index ff7e027616..a565229bb1 100644
--- a/tests/unit_tests/test_platformio_library.py
+++ b/tests/unit_tests/test_platformio_library.py
@@ -905,11 +905,11 @@ def test_split_flag_entry_non_string_is_clean() -> None:
 
 
 def test_source_kind_map_shape() -> None:
-    """The kind values the native compile rules key on, and the deliberate
-    AS/ASPP merge (.s and .S both map to asm)."""
+    """The kind values the native compile rules key on; the AS/ASPP split
+    matches SCons (.S preprocessed, .s plain assembler)."""
 
-    assert set(SOURCE_KIND_FOR_SUFFIX.values()) == {"c", "cxx", "asm"}
+    assert set(SOURCE_KIND_FOR_SUFFIX.values()) == {"c", "cxx", "asm", "aspp"}
     assert SOURCE_KIND_FOR_SUFFIX[".s"] == "asm"
-    assert SOURCE_KIND_FOR_SUFFIX[".S"] == "asm"
+    assert SOURCE_KIND_FOR_SUFFIX[".S"] == "aspp"
     assert SOURCE_KIND_FOR_SUFFIX[".c"] == "c"
     assert SOURCE_KIND_FOR_SUFFIX[".cpp"] == "cxx"