gh-107545: Fix misleading setsockopt error message

Lib/test/test_socket.py

@@ -1538,6 +1538,31 @@ def testSetSockOpt(self):
         reuse = sock.getsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR)
         self.assertFalse(reuse == 0, "failed to set reuse mode")
 
+    @unittest.skipIf(_testcapi is None, "requires _testcapi")
+    def test_setsockopt_errors(self):
+        # See issue #107546.
+        from _testcapi import INT_MAX, INT_MIN
+
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.addCleanup(sock.close)
+
+        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)  # No error expected.
+
+        with self.assertRaises(OverflowError):
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, INT_MAX + 1)
+
+        with self.assertRaises(OverflowError):
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, INT_MIN - 1)
+
+        with self.assertRaises(OverflowError):
+            sock.setsockopt(socket.SOL_SOCKET, INT_MAX + 1, 1)
+
+        with self.assertRaises(OverflowError):
+            sock.setsockopt(INT_MAX + 1, socket.SO_REUSEADDR, 1)
+
+        with self.assertRaises(TypeError):
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, dict())
+
     def testSendAfterClose(self):
         # testing send() after close() with timeout
         with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:

Misc/NEWS.d/next/Core_and_Builtins/2025-06-24-00-21-27.gh-issue-107545.GDa7Zs.rst

@@ -0,0 +1,2 @@
+Improve error message when :meth:`~socket.socket.setsockopt` raises an error
+other than a :exc:`TypeError`.

Modules/socketmodule.c

@@ -3373,6 +3373,9 @@ sock_setsockopt(PyObject *self, PyObject *args)
                          (char*)&flag, sizeof flag);
         goto done;
     }
+    if (!PyErr_ExceptionMatches(PyExc_TypeError)) {
+        return NULL;
+    }
 
     PyErr_Clear();
     /* setsockopt(level, opt, None, flag) */
@@ -3383,6 +3386,9 @@ sock_setsockopt(PyObject *self, PyObject *args)
                          NULL, (socklen_t)optlen);
         goto done;
     }
+    if (!PyErr_ExceptionMatches(PyExc_TypeError)) {
+        return NULL;
+    }
 
     PyErr_Clear();
     /* setsockopt(level, opt, buffer) */