From 3899429cfa5af617c2239b807b8c50e2d126a3da Mon Sep 17 00:00:00 2001
From: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
Date: Fri, 31 Jul 2026 12:34:44 +1200
Subject: [PATCH] [esp32] Restrict toolchain validation to supported values
 (#17972)

---
 esphome/components/esp32/__init__.py      |  4 +++-
 tests/component_tests/esp32/test_esp32.py | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/esphome/components/esp32/__init__.py b/esphome/components/esp32/__init__.py
index 8219b0c6d8..6491b9a5e6 100644
--- a/esphome/components/esp32/__init__.py
+++ b/esphome/components/esp32/__init__.py
@@ -1031,7 +1031,9 @@ def _check_esp_idf_versions(config: ConfigType) -> ConfigType:
 
 
 def _validate_toolchain(value) -> Toolchain:
-    return Toolchain(cv.one_of(*(t.value for t in Toolchain), lower=True)(value))
+    return Toolchain(
+        cv.one_of(Toolchain.PLATFORMIO, Toolchain.ESP_IDF, lower=True)(value)
+    )
 
 
 def _resolve_toolchain(value: ConfigType) -> ConfigType:
diff --git a/tests/component_tests/esp32/test_esp32.py b/tests/component_tests/esp32/test_esp32.py
index 4d18bbf6e4..c374e7c964 100644
--- a/tests/component_tests/esp32/test_esp32.py
+++ b/tests/component_tests/esp32/test_esp32.py
@@ -108,6 +108,24 @@ def test_esp32_default_toolchain_is_esp_idf(
     assert CORE.toolchain == expected
 
 
+@pytest.mark.parametrize(
+    "config_toolchain",
+    [Toolchain.SDK_NRF.value, "nonsense"],
+)
+def test_esp32_rejects_unsupported_toolchains(
+    set_core_config: SetCoreConfigCallable,
+    config_toolchain: str,
+) -> None:
+    """Toolchains esp32 does not support are rejected at validation time."""
+    set_core_config(PlatformFramework.ESP32_IDF)
+
+    from esphome.components.esp32 import CONFIG_SCHEMA
+
+    CORE.toolchain = None
+    with pytest.raises(cv.Invalid, match="Unknown value"):
+        CONFIG_SCHEMA({"variant": VARIANT_ESP32, "toolchain": config_toolchain})
+
+
 @pytest.mark.parametrize(
     ("config", "error_match"),
     [