gh-80931: Skip some socket tests while hunting for refleaks on macOS (#114057)

Some socket tests related to sending file descriptors cause a file descriptor leak on macOS, all of them tests that send one or more descriptors than cannot be received on the read end.  This appears to be a platform bug.

This PR skips those tests when doing a refleak test run to avoid hiding other problems.

Lib/test/libregrtest/refleak.py

@@ -5,6 +5,7 @@ from typing import Any
 
 from test import support
 from test.support import os_helper
+from test.support import refleak_helper
 
 from .runtests import HuntRefleak
 from .utils import clear_caches
@@ -96,7 +97,12 @@ def runtest_refleak(test_name, test_func,
     support.gc_collect()
 
     for i in rep_range:
-        results = test_func()
+        current = refleak_helper._hunting_for_refleaks
+        refleak_helper._hunting_for_refleaks = True
+        try:
+            results = test_func()
+        finally:
+            refleak_helper._hunting_for_refleaks = current
 
         dash_R_cleanup(fs, ps, pic, zdc, abcs)
         support.gc_collect()

Lib/test/support/refleak_helper.py

@@ -0,0 +1,8 @@
+"""
+Utilities for changing test behaviour while hunting
+for refleaks
+"""
+
+_hunting_for_refleaks = False
+def hunting_for_refleaks():
+    return _hunting_for_refleaks

Lib/test/test_socket.py

@@ -3,6 +3,7 @@ from test import support
 from test.support import os_helper
 from test.support import socket_helper
 from test.support import threading_helper
+from test.support import refleak_helper
 
 import _thread as thread
 import array
@@ -52,6 +53,35 @@ try:
 except ImportError:
     _socket = None
 
+def skipForRefleakHuntinIf(condition, issueref):
+    if not condition:
+        def decorator(f):
+            f.client_skip = lambda f: f
+            return f
+
+    else:
+        def decorator(f):
+            @contextlib.wraps(f)
+            def wrapper(*args, **kwds):
+                if refleak_helper.hunting_for_refleaks():
+                    raise unittest.SkipTest(f"ignore while hunting for refleaks, see {issueref}")
+
+                return f(*args, **kwds)
+
+            def client_skip(f):
+                @contextlib.wraps(f)
+                def wrapper(*args, **kwds):
+                    if refleak_helper.hunting_for_refleaks():
+                        return
+
+                    return f(*args, **kwds)
+
+                return wrapper
+            wrapper.client_skip = client_skip
+            return wrapper
+
+    return decorator
+
 def get_cid():
     if fcntl is None:
         return None
@@ -3814,6 +3844,7 @@ class SCMRightsTest(SendrecvmsgServerTimeoutBase):
         self.checkFlags(flags, eor=True, checkset=socket.MSG_CTRUNC,
                         ignore=ignoreflags)
 
+    @skipForRefleakHuntinIf(sys.platform == "darwin", "#80931")
     def testCmsgTruncNoBufSize(self):
         # Check that no ancillary data is received when no buffer size
         # is specified.
@@ -3823,26 +3854,32 @@ class SCMRightsTest(SendrecvmsgServerTimeoutBase):
                                   # received.
                                   ignoreflags=socket.MSG_CTRUNC)
 
+    @testCmsgTruncNoBufSize.client_skip
     def _testCmsgTruncNoBufSize(self):
         self.createAndSendFDs(1)
 
+    @skipForRefleakHuntinIf(sys.platform == "darwin", "#80931")
     def testCmsgTrunc0(self):
         # Check that no ancillary data is received when buffer size is 0.
         self.checkTruncatedHeader(self.doRecvmsg(self.serv_sock, len(MSG), 0),
                                   ignoreflags=socket.MSG_CTRUNC)
 
+    @testCmsgTrunc0.client_skip
     def _testCmsgTrunc0(self):
         self.createAndSendFDs(1)
 
     # Check that no ancillary data is returned for various non-zero
     # (but still too small) buffer sizes.
 
+    @skipForRefleakHuntinIf(sys.platform == "darwin", "#80931")
     def testCmsgTrunc1(self):
         self.checkTruncatedHeader(self.doRecvmsg(self.serv_sock, len(MSG), 1))
 
+    @testCmsgTrunc1.client_skip
     def _testCmsgTrunc1(self):
         self.createAndSendFDs(1)
 
+    @skipForRefleakHuntinIf(sys.platform == "darwin", "#80931")
     def testCmsgTrunc2Int(self):
         # The cmsghdr structure has at least three members, two of
         # which are ints, so we still shouldn't see any ancillary
@@ -3850,13 +3887,16 @@ class SCMRightsTest(SendrecvmsgServerTimeoutBase):
         self.checkTruncatedHeader(self.doRecvmsg(self.serv_sock, len(MSG),
                                                  SIZEOF_INT * 2))
 
+    @testCmsgTrunc2Int.client_skip
     def _testCmsgTrunc2Int(self):
         self.createAndSendFDs(1)
 
+    @skipForRefleakHuntinIf(sys.platform == "darwin", "#80931")
     def testCmsgTruncLen0Minus1(self):
         self.checkTruncatedHeader(self.doRecvmsg(self.serv_sock, len(MSG),
                                                  socket.CMSG_LEN(0) - 1))
 
+    @testCmsgTruncLen0Minus1.client_skip
     def _testCmsgTruncLen0Minus1(self):
         self.createAndSendFDs(1)
 
@@ -3887,29 +3927,38 @@ class SCMRightsTest(SendrecvmsgServerTimeoutBase):
                 len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
         self.checkFDs(fds)
 
+    @skipForRefleakHuntinIf(sys.platform == "darwin", "#80931")
     def testCmsgTruncLen0(self):
         self.checkTruncatedArray(ancbuf=socket.CMSG_LEN(0), maxdata=0)
 
+    @testCmsgTruncLen0.client_skip
     def _testCmsgTruncLen0(self):
         self.createAndSendFDs(1)
 
+    @skipForRefleakHuntinIf(sys.platform == "darwin", "#80931")
     def testCmsgTruncLen0Plus1(self):
         self.checkTruncatedArray(ancbuf=socket.CMSG_LEN(0) + 1, maxdata=1)
 
+    @testCmsgTruncLen0Plus1.client_skip
     def _testCmsgTruncLen0Plus1(self):
         self.createAndSendFDs(2)
 
+    @skipForRefleakHuntinIf(sys.platform == "darwin", "#80931")
     def testCmsgTruncLen1(self):
         self.checkTruncatedArray(ancbuf=socket.CMSG_LEN(SIZEOF_INT),
                                  maxdata=SIZEOF_INT)
 
+    @testCmsgTruncLen1.client_skip
     def _testCmsgTruncLen1(self):
         self.createAndSendFDs(2)
 
+
+    @skipForRefleakHuntinIf(sys.platform == "darwin", "#80931")
     def testCmsgTruncLen2Minus1(self):
         self.checkTruncatedArray(ancbuf=socket.CMSG_LEN(2 * SIZEOF_INT) - 1,
                                  maxdata=(2 * SIZEOF_INT) - 1)
 
+    @testCmsgTruncLen2Minus1.client_skip
     def _testCmsgTruncLen2Minus1(self):
         self.createAndSendFDs(2)