Make the testing-mode require explicit, reject a missing declared srcDir, and validate installs before marking success

esphome/arduino8266/component.py

@@ -17,7 +17,7 @@ from dataclasses import dataclass, field
 import logging
 from pathlib import Path
 
-from esphome.core import CORE, Library
+from esphome.core import CORE, EsphomeError, Library
 from esphome.espidf.extra_script import apply_extra_script
 from esphome.platformio.library import (
     DEFAULT_BUILD_INCLUDE_DIR,
@@ -68,9 +68,11 @@ def _library_info(name: str, read_path: Path, data: dict) -> ArduinoLibrary:
         (d for d in ("src", "Src") if (read_path / d).is_dir()), "."
     )
     if "srcDir" in build and not (read_path / src_dir).is_dir():
-        # A silently empty source set would surface as link errors instead
-        _LOGGER.warning(
-            "Library %s declares srcDir %s which does not exist", name, src_dir
+        # Unlike the default probes, an explicitly declared srcDir that does
+        # not resolve is unambiguously a manifest/tree error; a silently
+        # empty source set would surface as link errors far from the cause
+        raise EsphomeError(
+            f"Library {name} declares srcDir {src_dir} which does not exist"
         )
 
     src_filter = ensure_list(build.get("srcFilter", DEFAULT_BUILD_SRC_FILTER))

esphome/arduino8266/framework.py

@@ -17,6 +17,7 @@ toolchain has always used, so the bits are identical); the
 
 from __future__ import annotations
 
+from collections.abc import Collection
 import functools
 import logging
 import os
@@ -178,6 +179,7 @@ def _install_package(
     version: str,
     dest: Path,
     mirrors: list[str],
+    expect: Collection[str] = (),
 ) -> None:
     """Download, verify, and extract one package if not already installed.
 
@@ -207,6 +209,14 @@ def _install_package(
         download_with_resume(url, archive, sha256=sha256, size=size)
     _LOGGER.info("Extracting %s ...", name)
     archive_extract_all(archive, dest, progress_header="Extracting")
+    # Validate the layout before recording success, so an unexpected package
+    # is never cached as a working install.
+    for rel in expect:
+        if not (dest / rel).is_dir():
+            raise EsphomeError(
+                f"{name} {version} extracted without the expected {rel} "
+                "directory; run 'esphome clean-all' and retry"
+            )
     marker.touch()
     archive.unlink(missing_ok=True)
 
@@ -245,6 +255,7 @@ def check_and_install(framework_version: cv.Version) -> dict[str, Path]:
         package_version,
         framework_path,
         ESPHOME_ARDUINO8266_FRAMEWORK_MIRRORS,
+        expect=("cores/esp8266", "tools/sdk"),
     )
     toolchain_path = get_toolchain_path()
     _install_package(
@@ -252,6 +263,7 @@ def check_and_install(framework_version: cv.Version) -> dict[str, Path]:
         TOOLCHAIN_VERSION,
         toolchain_path,
         ESPHOME_ARDUINO8266_TOOLCHAIN_MIRRORS,
+        expect=("bin",),
     )
     return {
         "framework_path": framework_path,

esphome/build_gen/arduino8266.py

@@ -481,7 +481,8 @@ def write_project(paths: dict[str, Path]) -> bool:
     for required in include_dirs:
         if not required.is_dir():
             raise EsphomeError(
-                f"Arduino toolchain install is incomplete: missing {required}"
+                f"Arduino toolchain install is incomplete: missing {required}; "
+                "run 'esphome clean-all' and retry"
             )
     for lib in libraries:
         include_dirs += lib.include_dirs

esphome/components/esp8266/build_surgery.py

@@ -60,7 +60,7 @@ def _patch_segment_size(content: str, segment_name: str, new_size: str) -> str:
     return re.sub(pattern, rf"\g<1>{new_size}", content)
 
 
-def apply_testing_memory_patches(content: str, require: Collection[str] = ()) -> str:
+def apply_testing_memory_patches(content: str, require: Collection[str]) -> str:
     """Enlarge IRAM/DRAM/flash segments so grouped CI test builds can link.
 
     ``require`` names the segments this file must define; a silently