Expand ar response files in the shim and honor bundled library.json manifests

tests/unit_tests/build_gen/test_build_tool.py

@@ -27,7 +27,8 @@ def test_ar_removes_stale_archive(tmp_path: Path) -> None:
     ):
         assert build_tool.main() == 0
     assert not archive.exists()
-    assert mock_run.call_args[0][0] == ["ar-bin", "rc", str(archive), f"@{rsp}"]
+    # The rspfile is expanded by the shim (GNU ar would escape backslashes)
+    assert mock_run.call_args[0][0] == ["ar-bin", "rc", str(archive), "a.o"]
 
 
 def test_copy(tmp_path: Path) -> None:
@@ -61,3 +62,28 @@ def test_runs_as_script(tmp_path: Path) -> None:
     )
     assert result.returncode == 0
     assert dst.read_text() == "x"
+
+
+def test_ar_expands_rspfile_without_escaping(tmp_path) -> None:
+    """Backslash paths survive: the shim expands the rspfile itself instead
+    of letting GNU ar treat backslashes as escapes."""
+    rsp = tmp_path / "objs.rsp"
+    rsp.write_text("obj/a.o\nsub\\b.o\n")
+    with (
+        patch.object(
+            build_tool.sys,
+            "argv",
+            ["build_tool", "ar", "ar-bin", str(tmp_path / "lib.a"), str(rsp)],
+        ),
+        patch.object(
+            build_tool.subprocess, "run", return_value=MagicMock(returncode=0)
+        ) as mock_run,
+    ):
+        assert build_tool.main() == 0
+    assert mock_run.call_args[0][0] == [
+        "ar-bin",
+        "rc",
+        str(tmp_path / "lib.a"),
+        "obj/a.o",
+        "sub\\b.o",
+    ]

tests/unit_tests/test_arduino8266_component.py

@@ -304,3 +304,18 @@ def test_resolve_libraries_lib_ignore_covers_bundled_dependencies(
         libs = component.resolve_libraries(framework)
 
     assert [lib.name for lib in libs] == ["some__External"]
+
+
+def test_bundled_library_prefers_library_json(tmp_path: Path) -> None:
+    """A bundled library.json wins over library.properties (PIO semantics);
+    its build section is honored."""
+    framework = _make_framework(tmp_path)
+    lib_dir = framework / "libraries" / "GDBStub"
+    (lib_dir / "custom").mkdir(parents=True)
+    (lib_dir / "custom" / "gdb.cpp").write_text("")
+    (lib_dir / "library.properties").write_text("name=GDBStub\n")
+    (lib_dir / "library.json").write_text(
+        '{"name": "GDBStub", "build": {"srcDir": "custom"}}'
+    )
+    lib = component._bundled_library(framework, "GDBStub")
+    assert [s.name for s in lib.sources] == ["gdb.cpp"]