tests: Add test for recursive iternext stack overflow.

tests/misc/recursive_iternext.py

@@ -0,0 +1,33 @@
+# This tests that recursion with iternext doesn't lead to segfault.
+
+try:
+    x = (1, 2)
+    for i in range(1000):
+        x = enumerate(x)
+    tuple(x)
+except RuntimeError:
+    print("RuntimeError")
+
+try:
+    x = (1, 2)
+    for i in range(1000):
+        x = filter(None, x)
+    tuple(x)
+except RuntimeError:
+    print("RuntimeError")
+
+try:
+    x = (1, 2)
+    for i in range(1000):
+        x = map(max, x, ())
+    tuple(x)
+except RuntimeError:
+    print("RuntimeError")
+
+try:
+    x = (1, 2)
+    for i in range(1000):
+        x = zip(x)
+    tuple(x)
+except RuntimeError:
+    print("RuntimeError")

tests/misc/recursive_iternext.py.exp

@@ -0,0 +1,4 @@
+RuntimeError
+RuntimeError
+RuntimeError
+RuntimeError