bpo-34602: Avoid failures setting macOS stack resource limit (GH-14546) (GH-14549)

miss-islington · ned-deily · ned-deily · commit 782854f90ad5 · 2019-07-02T03:48:59.000-04:00
Under some conditions the earlier fix for bpo-18075, "Infinite recursion tests triggering a segfault on Mac OS X", now causes failures on macOS when attempting to change stack limit with resource.setrlimit resource.RLIMIT_STACK, like regrtest does when running the test suite. The reverted change had specified a non-default stack size when linking the python executable on macOS. As of macOS 10.14.4, the previous code causes a hard failure when running tests, although similar failures had been seen under some conditions under some earlier systems. Reverting the change to the interpreter stack size at link time helped for release builds but caused some tests to fail when built --with-pydebug. Try the opposite approach: continue to build the interpreter with an increased stack size on macOS and remove the failing setrlimit call in regrtest initialization. This will definitely avoid the resource.RLIMIT_STACK error and should have no, or fewer, side effects. (cherry picked from commit 5bbbc73) Co-authored-by: Ned Deily <nad@python.org>
diff --git a/Lib/test/libregrtest/setup.py b/Lib/test/libregrtest/setup.py
@@ -60,22 +60,6 @@ def setup_tests(ns):
         if getattr(module, '__file__', None):
             module.__file__ = os.path.abspath(module.__file__)
 
-    # MacOSX (a.k.a. Darwin) has a default stack size that is too small
-    # for deeply recursive regular expressions.  We see this as crashes in
-    # the Python test suite when running test_re.py and test_sre.py.  The
-    # fix is to set the stack limit to 2048.
-    # This approach may also be useful for other Unixy platforms that
-    # suffer from small default stack limits.
-    if sys.platform == 'darwin':
-        try:
-            import resource
-        except ImportError:
-            pass
-        else:
-            soft, hard = resource.getrlimit(resource.RLIMIT_STACK)
-            newsoft = min(hard, max(soft, 1024*2048))
-            resource.setrlimit(resource.RLIMIT_STACK, (newsoft, hard))
-
     if ns.huntrleaks:
         unittest.BaseTestSuite._cleanup = False
 
diff --git a/Misc/NEWS.d/next/macOS/2019-07-02-01-06-47.bpo-34602.10d4wl.rst b/Misc/NEWS.d/next/macOS/2019-07-02-01-06-47.bpo-34602.10d4wl.rst
@@ -0,0 +1,4 @@
+Avoid test suite failures on macOS by no longer calling resource.setrlimit
+to increase the process stack size limit at runtime.  The runtime change is
+no longer needed since the interpreter is being built with a larger default
+stack size.
diff --git a/configure b/configure
@@ -9504,6 +9504,12 @@ then
 	# -u libsys_s pulls in all symbols in libsys
 	Darwin/*)
 		LINKFORSHARED="$extra_undefs -framework CoreFoundation"
+
+		# 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
+		LINKFORSHARED="-Wl,-stack_size,1000000 $LINKFORSHARED"
+
 		if test "$enable_framework"
 		then
 			LINKFORSHARED="$LINKFORSHARED "'$(PYTHONFRAMEWORKDIR)/Versions/$(VERSION)/$(PYTHONFRAMEWORK)'
diff --git a/configure.ac b/configure.ac
@@ -2697,6 +2697,12 @@ then
 	# -u libsys_s pulls in all symbols in libsys
 	Darwin/*)
 		LINKFORSHARED="$extra_undefs -framework CoreFoundation"
+
+		# 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
+		LINKFORSHARED="-Wl,-stack_size,1000000 $LINKFORSHARED"
+
 		if test "$enable_framework"
 		then
 			LINKFORSHARED="$LINKFORSHARED "'$(PYTHONFRAMEWORKDIR)/Versions/$(VERSION)/$(PYTHONFRAMEWORK)'
