Make the remaining silent drops visible across backends

The depends=-without-dependencies warning moves into the shared walk so
espidf builds report it too; the arduino backend keeps it only for
bundled libraries the walk never sees. Version-less dependencies now
pass the platform filter before the reconciliation records them, so a
platform-excluded entry no longer draws a spurious drop warning.

A converted library whose matched files all fall through the source
suffix map warns instead of silently producing an empty archive, and
unhonored precompiled/ldflags properties fields warn by library name.
The ar rspfile parser undoes ninja's POSIX inner-quote escape and the
module docstring records the one-object-per-line contract. The
includeDir comment now states that warn-and-drop is intended.

esphome/arduino/library.py

@@ -6,7 +6,9 @@ library builds its own archive; all include dirs join one global path.
 
 Deviations from PlatformIO: flat-layout libraries get the recursive default
 source filter; ``dot_a_linkage`` is honored; bundled libraries never run a
-manifest ``extraScript``; manifest ``-I`` flags join the global include path.
+manifest ``extraScript``; manifest ``-I`` flags join the global include path;
+``precompiled``/``ldflags`` properties are not honored (a warning names the
+library).
 """
 
 from __future__ import annotations
@@ -36,6 +38,7 @@ from esphome.platformio.library import (
     normalize_dependencies,
     parse_library_json,
     parse_library_properties,
+    warn_properties_depends,
 )
 
 _LOGGER = logging.getLogger(__name__)
@@ -72,21 +75,6 @@ def _is_safe_library_name(name: object) -> bool:
     )
 
 
-def _warn_properties_depends(name: str, data: object) -> None:
-    """Warn when a manifest declares dependencies only as ``depends=``.
-
-    The dependency walk reads the JSON ``dependencies`` key; the raw
-    ``library.properties`` spelling would otherwise drop silently.
-    """
-    if isinstance(data, dict) and not data.get("dependencies") and data.get("depends"):
-        _LOGGER.warning(
-            "Library %s declares dependencies via library.properties "
-            "depends=, which are not resolved automatically; add them with "
-            "add_library() if needed",
-            name,
-        )
-
-
 def _manifest_build(name: str, data: object) -> dict:
     """The manifest's ``build`` section; a malformed manifest must fail
     naming the library, not with an AttributeError."""
@@ -114,6 +102,15 @@ def _library_info(name: str, read_path: Path, data: dict) -> ArduinoLibrary:
     else:
         src_dir = next((d for d in ("src", "Src") if (read_path / d).is_dir()), ".")
 
+    for dropped_key in ("precompiled", "ldflags"):
+        if data.get(dropped_key):
+            # PIO's Arduino lib builder honors these; building without them
+            # would fail far away at link with no stated cause
+            _LOGGER.warning(
+                "Library %s declares %s, which this backend does not honor",
+                name,
+                dropped_key,
+            )
     src_filter = ensure_list(build.get("srcFilter", DEFAULT_BUILD_SRC_FILTER))
     if not all(isinstance(entry, str) for entry in src_filter):
         raise EsphomeError(f"Library {name} has a malformed srcFilter")
@@ -170,24 +167,38 @@ def _library_info(name: str, read_path: Path, data: dict) -> ArduinoLibrary:
         if (path := (read_path / d)).is_dir():
             lib.include_dirs.append(path.resolve())
         elif explicit:
-            # The includeDir/srcDir defaults are probes; an explicitly
-            # declared path that does not resolve is a manifest error
+            # Warn-and-drop is intended (unlike srcDir, which raises): a
+            # missing include dir is harmless until a header is actually
+            # needed, and the compile names it then
             _LOGGER.warning(
                 "Library %s declares include dir %s which does not exist", name, d
             )
 
+    matched = collect_filtered_files(read_path / src_dir, src_filter)
     lib.sources = sorted(
         path.resolve()
-        for f in collect_filtered_files(read_path / src_dir, src_filter)
+        for f in matched
         if (path := Path(f)).suffix in SRC_FILE_EXTENSIONS
     )
-    if not lib.sources and ("srcFilter" in build or "srcDir" in build):
-        # A default probe finding nothing is a header-only library; a
-        # declared filter matching nothing is a manifest/tree problem.
-        _LOGGER.warning(
-            "Library %s declares srcFilter/srcDir but no source files matched",
-            name,
+    if skipped := [f for f in matched if Path(f).suffix not in SRC_FILE_EXTENSIONS]:
+        _LOGGER.debug(
+            "Library %s: %d matched files are not sources", name, len(skipped)
         )
+    if not lib.sources:
+        if matched:
+            # Every matched file fell through the suffix map: an empty
+            # archive would fail far away at link
+            _LOGGER.warning(
+                "Library %s: no matched file has a recognized source suffix",
+                name,
+            )
+        elif "srcFilter" in build or "srcDir" in build:
+            # A default probe finding nothing is a header-only library; a
+            # declared filter matching nothing is a manifest/tree problem.
+            _LOGGER.warning(
+                "Library %s declares srcFilter/srcDir but no source files matched",
+                name,
+            )
     return lib
 
 
@@ -213,7 +224,7 @@ def _bundled_library(framework_path: Path, name: str) -> ArduinoLibrary:
                 "resolved automatically; add them with add_library() if needed",
                 name,
             )
-        _warn_properties_depends(name, data)
+        warn_properties_depends(name, data)
         build = data.get("build")
         if isinstance(build, dict) and build.get("extraScript"):
             # apply_extra_script only runs on the converted path; a bundled
@@ -302,7 +313,6 @@ def resolve_libraries(
         # A version-less bare-name dependency ("Hash" in ESPAsyncWebServer)
         # is a core-bundled library; the shared converter skips it because
         # it cannot be resolved from the registry.
-        _warn_properties_depends(component.name, component.data)
         for dep in normalize_dependencies(
             component.data.get("dependencies"), component.name
         ):

esphome/build_gen/build_tool.py

@@ -6,6 +6,9 @@ started esphome and must not depend on the package being importable.
 Subcommands:
     ar <ar-binary> <archive> <rspfile>   remove stale archive, then ``ar rc``
     copy <src> <dst>                     copy a file
+
+The ar rspfile carries one object path per line (the generating rule must
+use ``$in_newline``, never ``$in``).
 """
 
 from pathlib import Path
@@ -24,8 +27,10 @@ def main() -> int:
         # GNU ar treats backslashes in response files as escapes (corrupts
         # Windows paths), so expand the rspfile into argv, stripping the
         # simple surrounding quote ninja adds to special paths.
+        # After stripping the outer pair, undo ninja's POSIX escape for an
+        # embedded quote ('a'\''b.o' -> a'b.o)
         objects = [
-            line[1:-1]
+            line[1:-1].replace("'\\''", "'")
             if len(line) >= 2 and line[0] == line[-1] and line[0] in "'\""
             else line
             for line in Path(rspfile).read_text(encoding="utf-8").splitlines()

esphome/platformio/library.py

@@ -628,6 +628,21 @@ def join_flag_args(tokens: Iterable[str], owner: str) -> list[str]:
     return out
 
 
+def warn_properties_depends(name: str, data: object) -> None:
+    """Warn when a manifest declares dependencies only as ``depends=``.
+
+    The dependency walk reads the JSON ``dependencies`` key; the raw
+    ``library.properties`` spelling would otherwise drop silently.
+    """
+    if isinstance(data, dict) and not data.get("dependencies") and data.get("depends"):
+        _LOGGER.warning(
+            "Library %s declares dependencies via library.properties "
+            "depends=, which are not resolved automatically; add them with "
+            "add_library() if needed",
+            name,
+        )
+
+
 def dependency_is_usable(
     dep: dict, platform: str | None, framework: str, requester: str
 ) -> bool:
@@ -1001,6 +1016,7 @@ def convert_libraries(
             # A bare json.load imposes no shape; every backend dereferences
             # data/build, so validate once here and name the library
             raise EsphomeError(f"Library {key} has a malformed manifest")
+        warn_properties_depends(component.name, component.data)
 
         try:
             check_library_data(component.data, backend.platform, backend.framework)
@@ -1036,7 +1052,13 @@ def convert_libraries(
                     dependency.get("name"),
                     component.name,
                 )
-                if not is_lib_ignored(dependency.get("name"), lib_ignore):
+                if not is_lib_ignored(
+                    dependency.get("name"), lib_ignore
+                ) and dependency_is_usable(
+                    dependency, backend.platform, backend.framework, component.name
+                ):
+                    # A platform-filtered or ignored dep is deliberately
+                    # absent, not a drop to reconcile
                     skipped_versionless.append(
                         (
                             dependency.get("name"),

tests/unit_tests/test_arduino_library.py

@@ -461,6 +461,31 @@ def test_library_info_lib_archive_parse(
     assert lib.lib_archive is expected
 
 
+def test_library_info_dropped_link_fields_warn(
+    tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """precompiled/ldflags properties are not honored; the drop is named."""
+    read_path = tmp_path / "lib"
+    (read_path / "src").mkdir(parents=True)
+    component._library_info(
+        "x", read_path, {"precompiled": "true", "ldflags": "-lfoo", "build": {}}
+    )
+    assert "declares precompiled, which this backend does not honor" in caplog.text
+    assert "declares ldflags, which this backend does not honor" in caplog.text
+
+
+def test_library_info_unmapped_sources_warn(
+    tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """Matched files that all fall through the suffix map are visible; an
+    empty archive would fail far away at link."""
+    read_path = tmp_path / "lib"
+    (read_path / "src").mkdir(parents=True)
+    (read_path / "src" / "impl.CPP").write_text("")
+    component._library_info("x", read_path, {"build": {}})
+    assert "no matched file has a recognized source suffix" in caplog.text
+
+
 def test_library_info_lib_archive_malformed_raises(tmp_path: Path) -> None:
     """A typo'd libArchive fails by name like the other build fields."""
     read_path = tmp_path / "lib"
@@ -645,18 +670,6 @@ def test_dict_shorthand_dependency_skips_registry_through_real_converter(
     assert any("locallib" in n.lower() for n in names)
 
 
-def test_converted_properties_depends_warns(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A converted library shipping only the properties depends= spelling
-    is visible, not a silent bundled-dependency drop."""
-    framework = _make_framework(tmp_path)
-    converted = _webserver(tmp_path, {"build": {}, "depends": "Wire,SPI"})
-    with _emitting_converter(converted):
-        _resolve(framework)
-    assert "declares dependencies via library.properties" in caplog.text
-
-
 @pytest.mark.parametrize(
     ("bad_name", "message"),
     [

tests/unit_tests/test_platformio_library.py

@@ -666,6 +666,40 @@ def test_convert_libraries_malformed_manifest_raises(
         convert_libraries([Library("esphome/A", None, None)], _backend())
 
 
+def test_walk_warns_for_properties_only_depends(
+    tmp_path, monkeypatch, caplog: pytest.LogCaptureFixture
+) -> None:
+    """A manifest declaring dependencies only as library.properties depends=
+    warns in the shared walk, so every backend reports the drop."""
+    _patch_download_with_manifests(
+        monkeypatch,
+        tmp_path,
+        {"esphome/A": "name=A\nversion=1.0\ndepends=Wire, SPI\n"},
+        properties=("esphome/A",),
+    )
+    convert_libraries([Library("esphome/A", "1.0.0", None)], _backend())
+    assert "declares dependencies via library.properties" in caplog.text
+
+
+def test_versionless_platform_filtered_dependency_stays_quiet(
+    tmp_path, monkeypatch, caplog: pytest.LogCaptureFixture
+) -> None:
+    """A version-less dependency the platform filter excludes is
+    deliberately absent, not a drop to warn about."""
+    _patch_download_with_manifests(
+        monkeypatch,
+        tmp_path,
+        {
+            "esphome/A": {
+                "name": "A",
+                "dependencies": [{"name": "Hash", "platforms": "espressif8266"}],
+            }
+        },
+    )
+    convert_libraries([Library("esphome/A", None, None)], _backend())
+    assert "has no version to resolve" not in caplog.text
+
+
 def test_versionless_ignored_dependency_stays_quiet(
     tmp_path, monkeypatch, caplog: pytest.LogCaptureFixture
 ) -> None: