GH-111808: Make the default value for test.support.infinite_recursion() conditional on compiler optimizations (GH-112223)

Co-authored-by: Victor Stinner <[email protected]>

Author: brettcannon

Lib/test/support/__init__.py

@@ -2120,13 +2120,21 @@ def set_recursion_limit(limit):
     finally:
         sys.setrecursionlimit(original_limit)
 
-def infinite_recursion(max_depth=100):
+def infinite_recursion(max_depth=None):
     """Set a lower limit for tests that interact with infinite recursions
     (e.g test_ast.ASTHelpers_Test.test_recursion_direct) since on some
     debug windows builds, due to not enough functions being inlined the
     stack size might not handle the default recursion limit (1000). See
     bpo-11105 for details."""
-    if max_depth < 3:
+    if max_depth is None:
+        if not python_is_optimized() or Py_DEBUG:
+            # Python built without compiler optimizations or in debug mode
+            # usually consumes more stack memory per function call.
+            # Unoptimized number based on what works under a WASI debug build.
+            max_depth = 50
+        else:
+            max_depth = 100
+    elif max_depth < 3:
         raise ValueError("max_depth must be at least 3, got {max_depth}")
     depth = get_recursion_depth()
     depth = max(depth - 1, 1)  # Ignore infinite_recursion() frame.

Lib/test/test_richcmp.py

@@ -221,7 +221,7 @@ def do(bad):
             self.assertRaises(Exc, func, Bad())
 
     @support.no_tracing
-    @support.infinite_recursion(25)
+    @support.infinite_recursion()
     def test_recursion(self):
         # Check that comparison for recursive objects fails gracefully
         from collections import UserList

Lib/test/test_typing.py

@@ -5621,7 +5621,7 @@ def fun(x: a): pass
         def cmp(o1, o2):
             return o1 == o2
 
-        with infinite_recursion(25):  # magic number, small but reasonable
+        with infinite_recursion():
             r1 = namespace1()
             r2 = namespace2()
             self.assertIsNot(r1, r2)

Misc/NEWS.d/next/Tests/2023-11-17-15-20-41.gh-issue-111808.jtIayt.rst

@@ -0,0 +1,4 @@
+Make the default value of ``test.support.infinite_recursion()`` to be
+conditional based on whether optimizations were used when compiling the
+interpreter. This helps with platforms like WASI whose stack size is greatly
+restricted in debug builds.