[core] Configure the platform again after prefetching its packages (#18830)

tests/unit_tests/test_platformio_prefetch.py

@@ -1417,6 +1417,76 @@ def test_prefetch_installs_cached_archives_without_downloads(
     assert not (tmp_path / pf._SENTINEL_NAME).exists()
 
 
+@pytest.mark.parametrize(
+    ("platform_group", "lib_group", "expected"),
+    [
+        (
+            [("toolchain-x@1", _FakeSpec(name="toolchain-x"))],
+            [],
+            ["configure", "install", "configure"],
+        ),
+        ([], [("noise-c@1.0", _FakeSpec(name="noise-c"))], ["configure", "install"]),
+    ],
+)
+def test_prefetch_reconfigures_only_after_platform_installs(
+    tmp_path: Path, platform_group: list, lib_group: list, expected: list[str]
+) -> None:
+    """Installed platform packages get a second configure pass; libraries do not."""
+    _write_ini(tmp_path, "[env:testenv]\nplatform = fake/p@1\n")
+    order: list[str] = []
+    fake_platform = MagicMock()
+    fake_platform.packages = {}
+    fake_platform.configure_project_packages.side_effect = lambda env, targets: (
+        order.append("configure")
+    )
+    config = _fake_config(
+        tmp_path, {"platform": "fake/p@1", "lib_deps": ["esphome/noise-c@1.0"]}
+    )
+    modules = _pio_modules(tmp_path, fake_platform, MagicMock(), config)
+    with (
+        patch.dict("sys.modules", modules),
+        patch.object(
+            pf,
+            "_registry_jobs",
+            side_effect=[([], 0, platform_group), ([], 0, lib_group)],
+        ),
+        patch.object(pf, "_uri_jobs", return_value=([], 0, [])),
+        patch.object(pf, "_preinstall", side_effect=lambda *_: order.append("install")),
+    ):
+        pf._prefetch(tmp_path, "testenv")
+    assert order == expected
+
+
+@pytest.mark.parametrize(
+    "err", [RuntimeError("idf_tools.py failed"), SystemExit("postinstall exited")]
+)
+def test_prefetch_settle_failure_warns_and_continues(
+    tmp_path: Path, caplog: pytest.LogCaptureFixture, err: BaseException
+) -> None:
+    """A failing second configure pass only costs the speedup."""
+    _write_ini(tmp_path, "[env:testenv]\nplatform = fake/p@1\n")
+    fake_platform = MagicMock()
+    fake_platform.packages = {}
+    fake_platform.configure_project_packages.side_effect = [None, err]
+    config = _fake_config(tmp_path, {"platform": "fake/p@1"})
+    modules = _pio_modules(tmp_path, fake_platform, MagicMock(), config)
+    with (
+        patch.dict("sys.modules", modules),
+        patch.object(
+            pf,
+            "_registry_jobs",
+            side_effect=[
+                ([], 0, [("toolchain-x@1", _FakeSpec(name="toolchain-x"))]),
+                ([], 0, []),
+            ],
+        ),
+        patch.object(pf, "_uri_jobs", return_value=([], 0, [])),
+        patch.object(pf, "_preinstall"),
+    ):
+        pf._prefetch(tmp_path, "testenv")
+    assert f"Could not settle platform packages: {err}" in caplog.text
+
+
 def test_preinstall_extracts_in_parallel_under_one_lock(tmp_path: Path) -> None:
     """The manager lock wraps the whole batch; per-thread managers share
     its package dir; one failing install leaves the rest alone."""