Fix exception mapping on OSX

Src/IronPython/Lib/iptest/__init__.py

@@ -2,7 +2,7 @@
 # The .NET Foundation licenses this file to you under the Apache 2.0 License.
 # See the LICENSE file in the project root for more information.
 
-from .ipunittest import IronPythonTestCase, stdout_trapper, stderr_trapper, path_modifier, retryOnFailure, run_test, skipUnlessIronPython, source_root
+from .ipunittest import IronPythonTestCase, stdout_trapper, stderr_trapper, path_modifier, retryOnFailure, run_test, skipUnlessIronPython, source_root, expectedFailureIf
 from .test_env import *
 from .type_util import *
 from .misc_util import ip_supported_encodings

Src/IronPython/Lib/iptest/ipunittest.py

@@ -53,6 +53,15 @@ def skipUnlessIronPython():
     """Skips the test unless currently running on IronPython"""
     return unittest.skipUnless(is_cli, 'IronPython specific test')
 
+def expectedFailureIf(condition):
+    """The test is marked as an expectedFailure if the condition is satisfied."""
+    def wrapper(func):
+        if condition:
+            return unittest.expectedFailure(func)
+        else:
+            return func
+    return wrapper
+
 MAX_FAILURE_RETRY = 3
 def retryOnFailure(f, times=MAX_FAILURE_RETRY, *args, **kwargs):
     '''

Src/IronPython/Runtime/Exceptions/PythonExceptions.cs

@@ -129,7 +129,7 @@ public partial class _OSError {
                             errno = WinErrorToErrno(winerror);
                         }
                     }
-                    cls = ErrnoToPythonType((Error)errno);
+                    cls = ErrnoToPythonType(ErrnoToErrorEnum(errno));
                 }
                 return Activator.CreateInstance(cls.UnderlyingSystemType, cls);
             }
@@ -183,25 +183,26 @@ public override void __init__(params object[] args) {
             }
 
             private enum Error {
+                UNSPECIFIED = -1,
                 EPERM = 1,
                 ENOENT = 2,
                 ESRCH = 3,
                 EINTR = 4,
                 ECHILD = 10,
-                EAGAIN = 11,
+                EAGAIN = 11, // 35 on OSX
                 EACCES = 13,
                 EEXIST = 17,
                 ENOTDIR = 20,
                 EISDIR = 21,
                 EPIPE = 32,
                 // Linux
-                ECONNABORTED = 103,
-                ECONNRESET = 104,
-                ESHUTDOWN = 108,
-                ETIMEDOUT = 110,
-                ECONNREFUSED = 111,
-                EALREADY = 114,
-                EINPROGRESS = 115,
+                ECONNABORTED = 103, // 53 on OSX
+                ECONNRESET = 104, // 54 on OSX
+                ESHUTDOWN = 108, // 58 on OSX
+                ETIMEDOUT = 110, // 60 on OSX
+                ECONNREFUSED = 111, // 61 on OSX
+                EALREADY = 114, // 37 on OSX
+                EINPROGRESS = 115, // 36 on OSX
                 // Windows
                 WSAEWOULDBLOCK = 10035,
                 WSAEINPROGRESS = 10036,
@@ -213,6 +214,14 @@ private enum Error {
                 WSAECONNREFUSED = 10061,
             }
 
+            private static Error ErrnoToErrorEnum(int errno) {
+                if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX)) {
+                    if (errno == 11) return Error.UNSPECIFIED; // EAGAIN on Linux/Windows but EDEADLK on OSX, which is not being remapped
+                    if (errno >= 35) errno += 10000; // add WSABASEERR to map to Windows error range
+                }
+                return (Error)errno;
+            }
+
             private static PythonType ErrnoToPythonType(Error errno) {
                 var res = errno switch
                 {
@@ -229,10 +238,10 @@ private static PythonType ErrnoToPythonType(Error errno) {
                     Error.EPIPE => BrokenPipeError,
                     _ => null
                 };
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows)) {
+                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || RuntimeInformation.IsOSPlatform(OSPlatform.OSX)) {
                     res ??= errno switch
                     {
-                        // Windows
+                        // Windows or remapped OSX
                         Error.WSAEWOULDBLOCK => BlockingIOError,
                         Error.WSAEINPROGRESS => BlockingIOError,
                         Error.WSAEALREADY => BlockingIOError,
@@ -243,8 +252,7 @@ private static PythonType ErrnoToPythonType(Error errno) {
                         Error.WSAECONNREFUSED => ConnectionRefusedError,
                         _ => null
                     };
-                } else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux) || RuntimeInformation.IsOSPlatform(OSPlatform.OSX)) {
-                    // TODO: verify that these are the same on OSX
+                } else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux)) {
                     res ??= errno switch
                     {
                         // Linux

Tests/test_exceptions.py

@@ -5,7 +5,7 @@
 import sys
 import unittest
 
-from iptest import IronPythonTestCase, is_cli, is_netcoreapp, run_test, skipUnlessIronPython
+from iptest import IronPythonTestCase, is_cli, is_netcoreapp, run_test, skipUnlessIronPython, expectedFailureIf
 
 class CP35300_Derived(EnvironmentError):
     def __init__(self, *args, **kwargs):
@@ -828,7 +828,7 @@ def __new__(cls, *args): return 42
         with self.assertRaises(TypeError): # TypeError: exceptions must derive from BaseException
             raise MyException('abc')
 
-    @unittest.expectedFailure # https://github.com/IronLanguages/ironpython3/issues/876
+    @expectedFailureIf(is_cli) # https://github.com/IronLanguages/ironpython3/issues/876
     def test_oserror_init(self):
         x = OSError()
         self.assertEqual(x.errno, None)
@@ -1025,6 +1025,39 @@ def test_windows_error(self):
         # winerror code is mapped to Python error code
         self.assertEqual(OSError('foo', 'bar', 'baz', 10).errno, 7)
 
+    def test_os_error_mapping(self):
+        import errno
+        import itertools
+
+        error_map = {
+            errno.EPERM : PermissionError,
+            errno.ENOENT : FileNotFoundError,
+            errno.ESRCH : ProcessLookupError,
+            errno.EINTR : InterruptedError,
+            errno.ECHILD : ChildProcessError,
+            errno.EAGAIN : BlockingIOError,
+            errno.EACCES : PermissionError,
+            errno.EEXIST : FileExistsError,
+            errno.ENOTDIR : NotADirectoryError,
+            errno.EISDIR : IsADirectoryError,
+            errno.EPIPE : BrokenPipeError,
+            errno.EWOULDBLOCK : BlockingIOError,
+            errno.ECONNABORTED : ConnectionAbortedError,
+            errno.ECONNRESET : ConnectionResetError,
+            errno.ESHUTDOWN : BrokenPipeError,
+            errno.ETIMEDOUT : TimeoutError,
+            errno.ECONNREFUSED : ConnectionRefusedError,
+            errno.EALREADY : BlockingIOError,
+            errno.EINPROGRESS : BlockingIOError,
+        }
+
+        for errno, exc in error_map.items():
+            self.assertIsInstance(OSError(errno, ''), exc)
+
+        for errno in itertools.chain(range(200), range(10000, 10200)):
+            if errno not in error_map:
+                self.assertIsInstance(OSError(errno, ''), OSError)
+
     def test_derived_keyword_args(self):
         class ED(Exception):
             def __init__(self, args=''):