Warn only for source-like suffix drops, batch ar argv, name non-iterable dependencies

The unmapped-suffix warning fired for every header-only library (the
default +<*> filter matches headers), so ArduinoJson would have warned
on every ESP8266 build. It now names exactly the source-like files
(.CPP, .ino and case-variants of the map) the case-sensitive suffix map
rejects, partial drops included, and stays quiet for headers and
metadata.

The ar shim batches the expanded object list by argv length (rc then q
appends), keeping the command line under the Windows 32767-char limit
the rspfile existed to avoid. A non-iterable dependencies value in a
manifest now warns by library name instead of raising a bare
TypeError.

tests/unit_tests/build_gen/test_build_tool.py

@@ -124,3 +124,48 @@ def test_ar_empty_object_list_fails(
         rc = build_tool.main()
     assert rc == 1
     assert "no objects listed" in capsys.readouterr().err
+
+
+def test_ar_batches_long_object_lists(tmp_path: Path) -> None:
+    """The expanded argv must stay under the Windows 32767-char limit: a
+    long object list creates with rc, then appends with q."""
+    archive = tmp_path / "lib.a"
+    rsp = tmp_path / "lib.a.rsp"
+    objects = [f"dir/{'x' * 120}_{i}.o" for i in range(400)]
+    rsp.write_text("\n".join(objects) + "\n")
+    with (
+        patch.object(
+            build_tool.sys,
+            "argv",
+            ["build_tool", "ar", "ar-bin", str(archive), str(rsp)],
+        ),
+        patch.object(
+            build_tool.subprocess, "run", return_value=MagicMock(returncode=0)
+        ) as mock_run,
+    ):
+        assert build_tool.main() == 0
+    calls = [c[0][0] for c in mock_run.call_args_list]
+    assert len(calls) > 1
+    assert calls[0][1] == "rc"
+    assert all(c[1] == "q" for c in calls[1:])
+    assert [o for c in calls for o in c[3:]] == objects
+    assert all(sum(len(a) + 1 for a in c) < 32000 for c in calls)
+
+
+def test_ar_batch_failure_stops(tmp_path: Path) -> None:
+    """A failing batch propagates its exit code without running the rest."""
+    archive = tmp_path / "lib.a"
+    rsp = tmp_path / "lib.a.rsp"
+    rsp.write_text("\n".join(f"{'y' * 200}_{i}.o" for i in range(300)) + "\n")
+    with (
+        patch.object(
+            build_tool.sys,
+            "argv",
+            ["build_tool", "ar", "ar-bin", str(archive), str(rsp)],
+        ),
+        patch.object(
+            build_tool.subprocess, "run", return_value=MagicMock(returncode=3)
+        ) as mock_run,
+    ):
+        assert build_tool.main() == 3
+    assert mock_run.call_count == 1

tests/unit_tests/test_arduino_library.py

@@ -477,13 +477,32 @@ def test_library_info_dropped_link_fields_warn(
 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."""
+    """Source-like files the case-sensitive suffix map rejects are named,
+    even when other sources compiled (a partial drop links with undefined
+    symbols far from the cause)."""
     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
+    (read_path / "src" / "sketch.ino").write_text("")
+    (read_path / "src" / "ok.cpp").write_text("")
+    lib = component._library_info("x", read_path, {"build": {}})
+    assert [s.name for s in lib.sources] == ["ok.cpp"]
+    assert "not compiled: impl.CPP, sketch.ino" in caplog.text
+
+
+def test_library_info_header_only_src_stays_quiet(
+    tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """A header-only library (real headers in src/) is routine, not a
+    warning (the default +<*> filter matches the headers too)."""
+    read_path = tmp_path / "lib"
+    (read_path / "src").mkdir(parents=True)
+    (read_path / "src" / "ArduinoJson.h").write_text("")
+    (read_path / "keywords.txt").write_text("")
+    lib = component._library_info("x", read_path, {"build": {}})
+    assert lib.sources == []
+    assert "not compiled" not in caplog.text
+    assert "srcFilter" not in caplog.text
 
 
 def test_library_info_lib_archive_malformed_raises(tmp_path: Path) -> None:

tests/unit_tests/test_platformio_library.py

@@ -645,6 +645,9 @@ def test_normalize_dependencies_forms(caplog) -> None:
         {"name": "SPI"},
     ]
     assert normalize_dependencies("Wire") == [{"name": "Wire"}]
+    # A non-iterable value fails by manifest name, never a bare TypeError
+    assert normalize_dependencies(5, "libx") == []
+    assert "Ignoring unrecognized dependencies 5 of libx" in caplog.text
     # The dict-shorthand form validates names like the list form: an empty
     # key and a spec overriding name with a non-string both warn and drop
     assert normalize_dependencies(