windows-result: unwrap FACILITY_WIN32 HRESULTs when converting to std::io::Error

[Copilot]

The From<Error> for std::io::Error impl in windows-result previously stored the full HRESULT into from_raw_os_error. Because Rust's std::io::Error::kind() on Windows decodes raw OS errors as Win32 error codes (small values), passing a full HRESULT meant ErrorKind for every Win32-origin error fell through to Uncategorized, defeating pattern matching.

This change unwraps HRESULTs whose facility is FACILITY_WIN32 into their underlying Win32 code via the existing WIN32_ERROR::from_error helper, while preserving the full HRESULT unchanged for HRESULTs from other facilities (E_FAIL, E_NOTIMPL, RPC/COM/custom facilities). This mirrors the conventions used by .NET's Marshal.GetExceptionForHR and Rust's own internal Win32 error decoding (option 2 from the issue discussion).

Tests

Updated crates/tests/misc/error/tests/std.rs to cover:

• ERROR_FILE_NOT_FOUND → ErrorKind::NotFound
• E_INVALIDARG (which is HRESULT_FROM_WIN32(ERROR_INVALID_PARAMETER)) unwraps to 87 → ErrorKind::InvalidInput
• ERROR_INVALID_DATA unwraps to its Win32 code (13) and formats with the expected message (no ErrorKind assertion, since Rust's std maps code 13 to Uncategorized)
• E_NOTIMPL, E_FAIL (non-FACILITY_WIN32) preserve the full HRESULT
• Round-trip ERROR_INVALID_DATA → std::io::Error → windows::core::Error is information-preserving

Note on behavior change

This is a behavioral change to a public From impl: HRESULTs with FACILITY_WIN32 now surface as their underlying Win32 code in std::io::Error::raw_os_error() rather than the full HRESULT. This is the explicit goal — to make ErrorKind matching work — but it affects existing users that read raw_os_error() expecting the full HRESULT. Non-FACILITY_WIN32 HRESULTs are unaffected.

[kennykerr]

@copilot fix test failure

[Copilot]

@copilot fix test failure

Fixed in cb52490. The arm64 Windows test was failing on assert_eq!(std_error.kind(), ErrorKind::InvalidData) for ERROR_INVALID_DATA (13) — Rust's std doesn't map that code to InvalidData (it falls through to Uncategorized). Removed that assertion; the NotFound and InvalidInput checks remain since those codes are decoded by Rust's std.

[Copilot]

Pull request overview

Adjusts windows-result’s From<windows::core::Error> for std::io::Error conversion so Win32-origin HRESULTs map to Win32 error codes in raw_os_error(), enabling meaningful std::io::Error::kind() matching on Windows.

Changes:

• Unwrap FACILITY_WIN32 HRESULTs to the underlying Win32 error code when converting Error -> std::io::Error.
• Extend tests to validate ErrorKind mapping for common Win32 codes and preserve non-Win32 HRESULT behavior.
• Add a round-trip test to ensure Win32 HRESULT information remains recoverable via std::io::Error -> windows::core::Error.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
crates/libs/result/src/error.rs	Updates From<Error> for std::io::Error to unwrap FACILITY_WIN32 HRESULTs to Win32 codes.
crates/tests/misc/error/tests/std.rs	Updates and expands conversion tests to cover ErrorKind decoding and round-trips.

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