bpo-18049: Sync thread stack size to main thread size on macOS (GH-14748)

This changeset increases the default size of the stack
for threads on macOS to the size of the stack
of the main thread and reenables the relevant
recursion test.

Lib/test/test_threading.py

@@ -1057,8 +1057,6 @@ class ThreadingExceptionTests(BaseTestCase):
         lock = threading.Lock()
         self.assertRaises(RuntimeError, lock.release)
 
-    @unittest.skipUnless(sys.platform == 'darwin' and test.support.python_is_optimized(),
-                         'test macosx problem')
     def test_recursion_limit(self):
         # Issue 9670
         # test that excessive recursion within a non-main thread causes

Misc/NEWS.d/next/macOS/2019-07-13-15-58-18.bpo-18049.MklhQQ.rst

+Increase the default stack size of threads from 5MB to 16MB on macOS, to
+match the stack size of the main thread. This avoids crashes on deep recursion
+in threads.

Python/thread_pthread.h

@@ -40,7 +40,8 @@
  */
 #if defined(__APPLE__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
 #undef  THREAD_STACK_SIZE
-#define THREAD_STACK_SIZE       0x500000
+/* Note: This matches the value of -Wl,-stack_size in configure.ac */
+#define THREAD_STACK_SIZE       0x1000000
 #endif
 #if defined(__FreeBSD__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
 #undef  THREAD_STACK_SIZE

configure

@@ -9542,6 +9542,8 @@ then
 		# Issue #18075: the default maximum stack size (8MBytes) is too
 		# small for the default recursion limit. Increase the stack size
 		# to ensure that tests don't crash
+		# Note: This matches the value of THREAD_STACK_SIZE in
+		# thread_pthread.h
 		LINKFORSHARED="-Wl,-stack_size,1000000 $LINKFORSHARED"
 
 		if test "$enable_framework"

configure.ac

@@ -2694,6 +2694,8 @@ then
 		# Issue #18075: the default maximum stack size (8MBytes) is too
 		# small for the default recursion limit. Increase the stack size
 		# to ensure that tests don't crash
+		# Note: This matches the value of THREAD_STACK_SIZE in
+		# thread_pthread.h
 		LINKFORSHARED="-Wl,-stack_size,1000000 $LINKFORSHARED"
 
 		if test "$enable_framework"