Cheroot ('s test suite?) is hardcoding error codes specific to x86 Linux

[mgorny]

❓ I'm submitting a ...

• 🐞 bug report
• 🐣 feature request
• ❓ question about the decisions made in the repository

🐞 Describe the bug. What is the current behavior?
At least the test suite (haven't checked other code) seems to hardcode a number of errno.h error codes, based on the values present on x86 Linux. This causes the tests to fail on other Linux architectures, particularly Alpha, MIPS, PA/RISC, SPARC.

❓ What is the motivation / use case for changing the behavior?
A passing test suite would help us verify that the package will work on expected on these architectures that aren't tested upstream.

💡 To Reproduce
Run pytest on one of the affected architectures.

💡 Expected behavior
The package not hardcoding errno values, and instead using the value obtained from the errno Python module.

📋 Details

For example, on Gentoo Linux SPARC we're seeing the following failures:

=================================== FAILURES ===================================
_______________ test_plat_specific_errors[err_names1-err_nums1] ________________

err_names = ('EPROTOTYPE', 'EAGAIN', 'EWOULDBLOCK', 'WSAEWOULDBLOCK', 'EPIPE')
err_nums = (91, 11, 32)

    @pytest.mark.parametrize(
        ('err_names', 'err_nums'),
        (
            (('', 'some-nonsense-name'), []),
            (
                (
                    'EPROTOTYPE', 'EAGAIN', 'EWOULDBLOCK',
                    'WSAEWOULDBLOCK', 'EPIPE',
                ),
                (91, 11, 32) if IS_LINUX else
                (32, 35, 41) if IS_MACOS else
                (98, 11, 32) if IS_SOLARIS else
                (32, 10041, 11, 10035) if IS_WINDOWS else
                (),
            ),
        ),
    )
    def test_plat_specific_errors(err_names, err_nums):
        """Test that ``plat_specific_errors`` gets correct error numbers list."""
        actual_err_nums = errors.plat_specific_errors(*err_names)
        assert len(actual_err_nums) == len(err_nums)
>       assert sorted(actual_err_nums) == sorted(err_nums)
E       assert [11, 32, 41] == [11, 32, 91]
E         
E         At index 2 diff: 41 != 91
E         
E         Full diff:
E           [
E               11,
E               32,
E         -     91,
E         ?     ^
E         +     41,
E         ?     ^
E           ]

actual_err_nums = [32, 41, 11]
err_names  = ('EPROTOTYPE', 'EAGAIN', 'EWOULDBLOCK', 'WSAEWOULDBLOCK', 'EPIPE')
err_nums   = (91, 11, 32)

cheroot/test/test_errors.py:31: AssertionError
_________________ test_http_over_https_error[0.0.0.0-builtin] __________________

http_request_timeout = 0.1
tls_http_server = functools.partial(<function make_tls_http_server at 0xfff800011772e2a0>, request=<SubRequest 'tls_http_server' for <Function test_http_over_https_error[0.0.0.0-builtin]>>)
adapter_type = 'builtin', ca = <trustme.CA object at 0xfff800011bab9cd0>
ip_addr = '0.0.0.0'
tls_certificate = <trustme.LeafCert object at 0xfff800011baf3230>
tls_certificate_chain_pem_path = '/var/tmp/portage/dev-python/cheroot-10.0.1/temp/tmpbg1u6oc_.pem'
tls_certificate_private_key_pem_path = '/var/tmp/portage/dev-python/cheroot-10.0.1/temp/tmp_toxj2g6.pem'

    @pytest.mark.parametrize(
        'adapter_type',
        (
            'builtin',
            'pyopenssl',
        ),
    )
    @pytest.mark.parametrize(
        'ip_addr',
        (
            ANY_INTERFACE_IPV4,
            pytest.param(ANY_INTERFACE_IPV6, marks=missing_ipv6),
        ),
    )
    @pytest.mark.flaky(reruns=3, reruns_delay=2)
    def test_http_over_https_error(
        http_request_timeout,
        tls_http_server, adapter_type,
        ca, ip_addr,
        tls_certificate,
        tls_certificate_chain_pem_path,
        tls_certificate_private_key_pem_path,
    ):
        """Ensure that connecting over HTTP to HTTPS port is handled."""
        # disable some flaky tests
        # https://github.com/cherrypy/cheroot/issues/225
        issue_225 = (
            IS_MACOS
            and adapter_type == 'builtin'
        )
        if issue_225:
            pytest.xfail('Test fails in Travis-CI')
    
        tls_adapter_cls = get_ssl_adapter_class(name=adapter_type)
        tls_adapter = tls_adapter_cls(
            tls_certificate_chain_pem_path, tls_certificate_private_key_pem_path,
        )
        if adapter_type == 'pyopenssl':
            tls_adapter.context = tls_adapter.get_context()
    
        tls_certificate.configure_cert(tls_adapter.context)
    
        interface, _host, port = _get_conn_data(ip_addr)
        tlshttpserver = tls_http_server((interface, port), tls_adapter)
    
        interface, _host, port = _get_conn_data(
            tlshttpserver.bind_addr,
        )
    
        fqdn = interface
        if ip_addr is ANY_INTERFACE_IPV6:
            fqdn = '[{fqdn}]'.format(**locals())
    
        expect_fallback_response_over_plain_http = (
            (
                adapter_type == 'pyopenssl'
            )
        )
        if expect_fallback_response_over_plain_http:
            resp = requests.get(
                'http://{host!s}:{port!s}/'.format(host=fqdn, port=port),
                timeout=http_request_timeout,
            )
            assert resp.status_code == 400
            assert resp.text == (
                'The client sent a plain HTTP request, '
                'but this server only speaks HTTPS on this port.'
            )
            return
    
        with pytest.raises(requests.exceptions.ConnectionError) as ssl_err:
            requests.get(  # FIXME: make stdlib ssl behave like PyOpenSSL
                'http://{host!s}:{port!s}/'.format(host=fqdn, port=port),
                timeout=http_request_timeout,
            )
    
        if IS_LINUX:
            expected_error_code, expected_error_text = (
                104, 'Connection reset by peer',
            )
        if IS_MACOS:
            expected_error_code, expected_error_text = (
                54, 'Connection reset by peer',
            )
        if IS_WINDOWS:
            expected_error_code, expected_error_text = (
                10054,
                'An existing connection was forcibly closed by the remote host',
            )
    
        underlying_error = ssl_err.value.args[0].args[-1]
        err_text = str(underlying_error)
>       assert underlying_error.errno == expected_error_code, (
            'The underlying error is {underlying_error!r}'.
            format(**locals())
        )
E       AssertionError: The underlying error is ConnectionResetError(54, 'Connection reset by peer')
E       assert 54 == 104
E        +  where 54 = ConnectionResetError(54, 'Connection reset by peer').errno

_host      = '127.0.0.1'
adapter_type = 'builtin'
ca         = <trustme.CA object at 0xfff800011bab9cd0>
err_text   = '[Errno 54] Connection reset by peer'
expect_fallback_response_over_plain_http = False
expected_error_code = 104
expected_error_text = 'Connection reset by peer'
fqdn       = '127.0.0.1'
http_request_timeout = 0.1
interface  = '127.0.0.1'
ip_addr    = '0.0.0.0'
issue_225  = False
port       = 37263
ssl_err    = <ExceptionInfo ConnectionError(ProtocolError('Connection aborted.', ConnectionResetError(54, 'Connection reset by peer'))) tblen=6>
tls_adapter = <cheroot.ssl.builtin.BuiltinSSLAdapter object at 0xfff800011be1fe60>
tls_adapter_cls = <class 'cheroot.ssl.builtin.BuiltinSSLAdapter'>
tls_certificate = <trustme.LeafCert object at 0xfff800011baf3230>
tls_certificate_chain_pem_path = '/var/tmp/portage/dev-python/cheroot-10.0.1/temp/tmpbg1u6oc_.pem'
tls_certificate_private_key_pem_path = '/var/tmp/portage/dev-python/cheroot-10.0.1/temp/tmp_toxj2g6.pem'
tls_http_server = functools.partial(<function make_tls_http_server at 0xfff800011772e2a0>, request=<SubRequest 'tls_http_server' for <Function test_http_over_https_error[0.0.0.0-builtin]>>)
tlshttpserver = <cheroot.server.HTTPServer object at 0xfff800011be3e7b0>
underlying_error = ConnectionResetError(54, 'Connection reset by peer')

cheroot/test/test_ssl.py:697: AssertionError
----------------------------- Captured stderr call -----------------------------
Client ('127.0.0.1', 50238) attempted to speak plain HTTP into a TCP connection configured for TLS-only traffic — trying to send back a plain HTTP error response: (1, '[SSL: HTTP_REQUEST] http request (_ssl.c:1004)')
____________________ test_http_over_https_error[::-builtin] ____________________

http_request_timeout = 0.1
tls_http_server = functools.partial(<function make_tls_http_server at 0xfff800011772e2a0>, request=<SubRequest 'tls_http_server' for <Function test_http_over_https_error[::-builtin]>>)
adapter_type = 'builtin', ca = <trustme.CA object at 0xfff800011be69100>
ip_addr = '::'
tls_certificate = <trustme.LeafCert object at 0xfff800011b060c80>
tls_certificate_chain_pem_path = '/var/tmp/portage/dev-python/cheroot-10.0.1/temp/tmpeqe56lh4.pem'
tls_certificate_private_key_pem_path = '/var/tmp/portage/dev-python/cheroot-10.0.1/temp/tmptjfpplob.pem'

    @pytest.mark.parametrize(
        'adapter_type',
        (
            'builtin',
            'pyopenssl',
        ),
    )
    @pytest.mark.parametrize(
        'ip_addr',
        (
            ANY_INTERFACE_IPV4,
            pytest.param(ANY_INTERFACE_IPV6, marks=missing_ipv6),
        ),
    )
    @pytest.mark.flaky(reruns=3, reruns_delay=2)
    def test_http_over_https_error(
        http_request_timeout,
        tls_http_server, adapter_type,
        ca, ip_addr,
        tls_certificate,
        tls_certificate_chain_pem_path,
        tls_certificate_private_key_pem_path,
    ):
        """Ensure that connecting over HTTP to HTTPS port is handled."""
        # disable some flaky tests
        # https://github.com/cherrypy/cheroot/issues/225
        issue_225 = (
            IS_MACOS
            and adapter_type == 'builtin'
        )
        if issue_225:
            pytest.xfail('Test fails in Travis-CI')
    
        tls_adapter_cls = get_ssl_adapter_class(name=adapter_type)
        tls_adapter = tls_adapter_cls(
            tls_certificate_chain_pem_path, tls_certificate_private_key_pem_path,
        )
        if adapter_type == 'pyopenssl':
            tls_adapter.context = tls_adapter.get_context()
    
        tls_certificate.configure_cert(tls_adapter.context)
    
        interface, _host, port = _get_conn_data(ip_addr)
        tlshttpserver = tls_http_server((interface, port), tls_adapter)
    
        interface, _host, port = _get_conn_data(
            tlshttpserver.bind_addr,
        )
    
        fqdn = interface
        if ip_addr is ANY_INTERFACE_IPV6:
            fqdn = '[{fqdn}]'.format(**locals())
    
        expect_fallback_response_over_plain_http = (
            (
                adapter_type == 'pyopenssl'
            )
        )
        if expect_fallback_response_over_plain_http:
            resp = requests.get(
                'http://{host!s}:{port!s}/'.format(host=fqdn, port=port),
                timeout=http_request_timeout,
            )
            assert resp.status_code == 400
            assert resp.text == (
                'The client sent a plain HTTP request, '
                'but this server only speaks HTTPS on this port.'
            )
            return
    
        with pytest.raises(requests.exceptions.ConnectionError) as ssl_err:
            requests.get(  # FIXME: make stdlib ssl behave like PyOpenSSL
                'http://{host!s}:{port!s}/'.format(host=fqdn, port=port),
                timeout=http_request_timeout,
            )
    
        if IS_LINUX:
            expected_error_code, expected_error_text = (
                104, 'Connection reset by peer',
            )
        if IS_MACOS:
            expected_error_code, expected_error_text = (
                54, 'Connection reset by peer',
            )
        if IS_WINDOWS:
            expected_error_code, expected_error_text = (
                10054,
                'An existing connection was forcibly closed by the remote host',
            )
    
        underlying_error = ssl_err.value.args[0].args[-1]
        err_text = str(underlying_error)
>       assert underlying_error.errno == expected_error_code, (
            'The underlying error is {underlying_error!r}'.
            format(**locals())
        )
E       AssertionError: The underlying error is ConnectionResetError(54, 'Connection reset by peer')
E       assert 54 == 104
E        +  where 54 = ConnectionResetError(54, 'Connection reset by peer').errno

_host      = '::1'
adapter_type = 'builtin'
ca         = <trustme.CA object at 0xfff800011be69100>
err_text   = '[Errno 54] Connection reset by peer'
expect_fallback_response_over_plain_http = False
expected_error_code = 104
expected_error_text = 'Connection reset by peer'
fqdn       = '[::1]'
http_request_timeout = 0.1
interface  = '::1'
ip_addr    = '::'
issue_225  = False
port       = 48763
ssl_err    = <ExceptionInfo ConnectionError(ProtocolError('Connection aborted.', ConnectionResetError(54, 'Connection reset by peer'))) tblen=6>
tls_adapter = <cheroot.ssl.builtin.BuiltinSSLAdapter object at 0xfff800011beadf70>
tls_adapter_cls = <class 'cheroot.ssl.builtin.BuiltinSSLAdapter'>
tls_certificate = <trustme.LeafCert object at 0xfff800011b060c80>
tls_certificate_chain_pem_path = '/var/tmp/portage/dev-python/cheroot-10.0.1/temp/tmpeqe56lh4.pem'
tls_certificate_private_key_pem_path = '/var/tmp/portage/dev-python/cheroot-10.0.1/temp/tmptjfpplob.pem'
tls_http_server = functools.partial(<function make_tls_http_server at 0xfff800011772e2a0>, request=<SubRequest 'tls_http_server' for <Function test_http_over_https_error[::-builtin]>>)
tlshttpserver = <cheroot.server.HTTPServer object at 0xfff800011beae390>
underlying_error = ConnectionResetError(54, 'Connection reset by peer')

cheroot/test/test_ssl.py:697: AssertionError
----------------------------- Captured stderr call -----------------------------
Client ('::1', 36804, 0, 0) attempted to speak plain HTTP into a TCP connection configured for TLS-only traffic — trying to send back a plain HTTP error response: (1, '[SSL: HTTP_REQUEST] http request (_ssl.c:1004)')

📋 Environment

• Cheroot version: 10.0.1
• CherryPy version: 18.10.0
• Python version: 3.12.7
• OS: Gentoo Linux
• Browser: n/a

📋 Additional context
The arch-specific errno values can be found in the Linux kernel sources, e.g.:

$ grep -R '#define.*EPROTOTYPE' arch
arch/alpha/include/uapi/asm/errno.h:#define	EPROTOTYPE	41	/* Protocol wrong type for socket */
arch/mips/include/uapi/asm/errno.h:#define EPROTOTYPE	98	/* Protocol wrong type for socket */
arch/parisc/include/uapi/asm/errno.h:#define	EPROTOTYPE	219	/* Protocol wrong type for socket */
arch/sparc/include/uapi/asm/errno.h:#define	EPROTOTYPE	41	/* Protocol wrong type for socket */

[webknjaz]

Yeah… I'm not happy about this, either. I've been meaning to come up with a better way, given how much problems said errors cause even in the runtime code. Thanks for documenting this!