bpo-18174: regrtest -R 3:3 checks for handle leak

Lib/test/libregrtest/refleak.py

@@ -13,6 +13,12 @@ def _get_dump(cls):
         return (cls._abc_registry, cls._abc_cache,
                 cls._abc_negative_cache, cls._abc_negative_cache_version)
 
+if sys.platform == 'win32':
+    from _winapi import GetProcessHandleCount as handle_count
+else:
+    def handle_count():
+        return 0
+
 
 def dash_R(the_module, test, indirect_test, huntrleaks):
     """Run a test multiple times, looking for reference leaks.
@@ -59,24 +65,27 @@ def get_pooled_int(value):
     rc_deltas = [0] * repcount
     alloc_deltas = [0] * repcount
     fd_deltas = [0] * repcount
+    handle_deltas = [0] * repcount
 
     print("beginning", repcount, "repetitions", file=sys.stderr)
     print(("1234567890"*(repcount//10 + 1))[:repcount], file=sys.stderr,
           flush=True)
     # initialize variables to make pyflakes quiet
-    rc_before = alloc_before = fd_before = 0
+    rc_before = alloc_before = fd_before = handle_before = 0
     for i in range(repcount):
         indirect_test()
-        alloc_after, rc_after, fd_after = dash_R_cleanup(fs, ps, pic, zdc,
-                                                         abcs)
+        result = dash_R_cleanup(fs, ps, pic, zdc, abcs)
+        alloc_after, rc_after, fd_after, handle_after = result
         print('.', end='', file=sys.stderr, flush=True)
         if i >= nwarmup:
             rc_deltas[i] = get_pooled_int(rc_after - rc_before)
             alloc_deltas[i] = get_pooled_int(alloc_after - alloc_before)
             fd_deltas[i] = get_pooled_int(fd_after - fd_before)
+            handle_deltas[i] = get_pooled_int(handle_after - handle_before)
         alloc_before = alloc_after
         rc_before = rc_after
         fd_before = fd_after
+        handle_before = handle_after
     print(file=sys.stderr)
 
     # These checkers return False on success, True on failure
@@ -102,7 +111,8 @@ def check_fd_deltas(deltas):
     for deltas, item_name, checker in [
         (rc_deltas, 'references', check_rc_deltas),
         (alloc_deltas, 'memory blocks', check_rc_deltas),
-        (fd_deltas, 'file descriptors', check_fd_deltas)
+        (fd_deltas, 'file descriptors', check_fd_deltas),
+        (handle_deltas, 'handles', check_rc_deltas),
     ]:
         # ignore warmup runs
         deltas = deltas[nwarmup:]
@@ -154,7 +164,7 @@ def dash_R_cleanup(fs, ps, pic, zdc, abcs):
     func1 = sys.getallocatedblocks
     func2 = sys.gettotalrefcount
     gc.collect()
-    return func1(), func2(), support.fd_count()
+    return func1(), func2(), support.fd_count(), handle_count()
 
 
 def clear_caches():

Lib/test/test_regrtest.py

@@ -857,6 +857,28 @@ def test_leak(self):
         """)
         self.check_leak(code, 'file descriptors')
 
+    @unittest.skipUnless(sys.platform == 'win32', 'specific to Windows')
+    @unittest.skipUnless(Py_DEBUG, 'need a debug build')
+    def test_huntrleaks_handle_leak(self):
+        # test --huntrleaks for file descriptor leak
+        code = textwrap.dedent("""
+            import os
+            import unittest
+            import _winapi
+
+            process = _winapi.GetCurrentProcess()
+            handle = process
+
+            class FDLeakTest(unittest.TestCase):
+                def test_leak(self):
+                    handle2 = _winapi.DuplicateHandle(
+                        process, handle, process,
+                        0, 1,
+                        _winapi.DUPLICATE_SAME_ACCESS)
+                    # bug: never close handle2
+        """)
+        self.check_leak(code, 'handles')
+
     def test_list_tests(self):
         # test --list-tests
         tests = [self.create_test() for i in range(5)]

Misc/NEWS.d/next/Tests/2018-06-20-16-55-12.bpo-18174.343gmT.rst

@@ -0,0 +1,2 @@
+regrtest now also checks for leak of Windows handles. Initial patch written
+by Richard Oudkerk.

Modules/_winapi.c

@@ -1229,6 +1229,33 @@ _winapi_GetModuleFileName_impl(PyObject *module, HMODULE module_handle)
     return PyUnicode_FromWideChar(filename, wcslen(filename));
 }
 
+/*[clinic input]
+_winapi.GetProcessHandleCount
+
+    ProcessHandle: HANDLE(c_default="GetCurrentProcess()") = NULL
+    /
+
+Return the number of open handles for the specified process.
+
+Return the number of open handles for the process specified
+by ProcessHandle.  If ProcessHandle is not given then the
+handle count for the current process is given.
+
+[clinic start generated code]*/
+
+static PyObject *
+_winapi_GetProcessHandleCount_impl(PyObject *module, HANDLE ProcessHandle)
+/*[clinic end generated code: output=af58910c23922016 input=089cb7546e598a2d]*/
+{
+    DWORD HandleCount;
+
+    if (!GetProcessHandleCount(ProcessHandle, &HandleCount))
+        return PyErr_SetFromWindowsErr(0);
+
+    return PyLong_FromUnsignedLong(HandleCount);
+}
+
+
 /*[clinic input]
 _winapi.GetStdHandle -> HANDLE
 
@@ -1714,6 +1741,7 @@ static PyMethodDef winapi_functions[] = {
     _WINAPI_GETEXITCODEPROCESS_METHODDEF
     _WINAPI_GETLASTERROR_METHODDEF
     _WINAPI_GETMODULEFILENAME_METHODDEF
+    _WINAPI_GETPROCESSHANDLECOUNT_METHODDEF
     _WINAPI_GETSTDHANDLE_METHODDEF
     _WINAPI_GETVERSION_METHODDEF
     _WINAPI_OPENPROCESS_METHODDEF