[platformio] Add exponential backoff and session reset to download retries (#14191)

tests/unit_tests/test_platformio_api.py

@@ -6,7 +6,7 @@ import os
 from pathlib import Path
 import shutil
 from types import SimpleNamespace
-from unittest.mock import MagicMock, Mock, patch
+from unittest.mock import MagicMock, Mock, call, patch
 
 import pytest
 
@@ -673,6 +673,200 @@ def test_process_stacktrace_bad_alloc(
     assert state is False
 
 
+def test_patch_file_downloader_succeeds_first_try() -> None:
+    """Test patch_file_downloader succeeds on first attempt."""
+    mock_exception_cls = type("PackageException", (Exception,), {})
+    original_init = MagicMock()
+
+    with patch.dict(
+        "sys.modules",
+        {
+            "platformio": MagicMock(),
+            "platformio.package": MagicMock(),
+            "platformio.package.download": SimpleNamespace(
+                FileDownloader=type("FileDownloader", (), {"__init__": original_init})
+            ),
+            "platformio.package.exception": SimpleNamespace(
+                PackageException=mock_exception_cls
+            ),
+        },
+    ):
+        platformio_api.patch_file_downloader()
+
+        from platformio.package.download import FileDownloader
+
+        instance = object.__new__(FileDownloader)
+        FileDownloader.__init__(instance, "http://example.com/file.zip")
+
+        original_init.assert_called_once()
+
+
+def test_patch_file_downloader_retries_on_failure() -> None:
+    """Test patch_file_downloader retries with backoff on PackageException."""
+    mock_exception_cls = type("PackageException", (Exception,), {})
+    call_count = 0
+
+    def failing_init(self, *args, **kwargs):
+        nonlocal call_count
+        call_count += 1
+        if call_count < 3:
+            raise mock_exception_cls(f"502 error attempt {call_count}")
+
+    with (
+        patch.dict(
+            "sys.modules",
+            {
+                "platformio": MagicMock(),
+                "platformio.package": MagicMock(),
+                "platformio.package.download": SimpleNamespace(
+                    FileDownloader=type(
+                        "FileDownloader", (), {"__init__": failing_init}
+                    )
+                ),
+                "platformio.package.exception": SimpleNamespace(
+                    PackageException=mock_exception_cls
+                ),
+            },
+        ),
+        patch("time.sleep") as mock_sleep,
+    ):
+        platformio_api.patch_file_downloader()
+
+        from platformio.package.download import FileDownloader
+
+        instance = object.__new__(FileDownloader)
+        FileDownloader.__init__(instance, "http://example.com/file.zip")
+
+        # Should have been called 3 times (2 failures + 1 success)
+        assert call_count == 3
+
+        # Should have slept with exponential backoff: 2s, 4s
+        assert mock_sleep.call_count == 2
+        mock_sleep.assert_any_call(2)
+        mock_sleep.assert_any_call(4)
+
+
+def test_patch_file_downloader_raises_after_max_retries() -> None:
+    """Test patch_file_downloader raises after exhausting all retries."""
+    mock_exception_cls = type("PackageException", (Exception,), {})
+
+    def always_failing_init(self, *args, **kwargs):
+        raise mock_exception_cls("502 error")
+
+    with (
+        patch.dict(
+            "sys.modules",
+            {
+                "platformio": MagicMock(),
+                "platformio.package": MagicMock(),
+                "platformio.package.download": SimpleNamespace(
+                    FileDownloader=type(
+                        "FileDownloader", (), {"__init__": always_failing_init}
+                    )
+                ),
+                "platformio.package.exception": SimpleNamespace(
+                    PackageException=mock_exception_cls
+                ),
+            },
+        ),
+        patch("time.sleep") as mock_sleep,
+    ):
+        platformio_api.patch_file_downloader()
+
+        from platformio.package.download import FileDownloader
+
+        instance = object.__new__(FileDownloader)
+        with pytest.raises(mock_exception_cls, match="502 error"):
+            FileDownloader.__init__(instance, "http://example.com/file.zip")
+
+        # Should have slept 4 times (before attempts 2-5), not on final attempt
+        assert mock_sleep.call_count == 4
+        mock_sleep.assert_has_calls([call(2), call(4), call(8), call(16)])
+
+
+def test_patch_file_downloader_closes_session_and_response_between_retries() -> None:
+    """Test patch_file_downloader closes HTTP session and response between retries."""
+    mock_exception_cls = type("PackageException", (Exception,), {})
+    mock_session = MagicMock()
+    mock_response = MagicMock()
+    call_count = 0
+
+    def failing_init_with_session(self, *args, **kwargs):
+        nonlocal call_count
+        call_count += 1
+        self._http_session = mock_session
+        self._http_response = mock_response
+        if call_count < 2:
+            raise mock_exception_cls("502 error")
+
+    with (
+        patch.dict(
+            "sys.modules",
+            {
+                "platformio": MagicMock(),
+                "platformio.package": MagicMock(),
+                "platformio.package.download": SimpleNamespace(
+                    FileDownloader=type(
+                        "FileDownloader",
+                        (),
+                        {"__init__": failing_init_with_session},
+                    )
+                ),
+                "platformio.package.exception": SimpleNamespace(
+                    PackageException=mock_exception_cls
+                ),
+            },
+        ),
+        patch("time.sleep"),
+    ):
+        platformio_api.patch_file_downloader()
+
+        from platformio.package.download import FileDownloader
+
+        instance = object.__new__(FileDownloader)
+        FileDownloader.__init__(instance, "http://example.com/file.zip")
+
+        # Both response and session should have been closed between retries
+        mock_response.close.assert_called_once()
+        mock_session.close.assert_called_once()
+
+
+def test_patch_file_downloader_idempotent() -> None:
+    """Test patch_file_downloader does not stack wrappers when called multiple times."""
+    mock_exception_cls = type("PackageException", (Exception,), {})
+    call_count = 0
+
+    def counting_init(self, *args, **kwargs):
+        nonlocal call_count
+        call_count += 1
+
+    with patch.dict(
+        "sys.modules",
+        {
+            "platformio": MagicMock(),
+            "platformio.package": MagicMock(),
+            "platformio.package.download": SimpleNamespace(
+                FileDownloader=type("FileDownloader", (), {"__init__": counting_init})
+            ),
+            "platformio.package.exception": SimpleNamespace(
+                PackageException=mock_exception_cls
+            ),
+        },
+    ):
+        # Patch multiple times
+        platformio_api.patch_file_downloader()
+        platformio_api.patch_file_downloader()
+        platformio_api.patch_file_downloader()
+
+        from platformio.package.download import FileDownloader
+
+        instance = object.__new__(FileDownloader)
+        FileDownloader.__init__(instance, "http://example.com/file.zip")
+
+        # Should only be called once, not 3 times from stacked wrappers
+        assert call_count == 1
+
+
 def test_platformio_log_filter_allows_non_platformio_messages() -> None:
     """Test that non-platformio logger messages are allowed through."""
     log_filter = platformio_api.PlatformioLogFilter()