gh-135028: Increase parser MAXSTACK for nested parenthesis (#135031)

Lib/test/test_grammar.py

@@ -1,7 +1,7 @@
 # Python test set -- part 1, grammar.
 # This just tests whether the parser accepts them all.
 
-from test.support import check_syntax_error
+from test.support import check_syntax_error, skip_wasi_stack_overflow
 from test.support import import_helper
 import annotationlib
 import inspect
@@ -249,6 +249,18 @@ the \'lazy\' dog.\n\
                 compile(s, "<test>", "exec")
             self.assertIn("was never closed", str(cm.exception))
 
+    @skip_wasi_stack_overflow()
+    def test_max_level(self):
+        # Macro defined in Parser/lexer/state.h
+        MAXLEVEL = 200
+
+        result = eval("(" * MAXLEVEL + ")" * MAXLEVEL)
+        self.assertEqual(result, ())
+
+        with self.assertRaises(SyntaxError) as cm:
+            eval("(" * (MAXLEVEL + 1) + ")" * (MAXLEVEL + 1))
+        self.assertStartsWith(str(cm.exception), 'too many nested parentheses')
+
 var_annot_global: int # a global annotated is necessary for test_var_annot
 
 

Parser/parser.c

@@ -14,7 +14,7 @@
 #    define MAXSTACK 4000
 #  endif
 #else
-#  define MAXSTACK 4000
+#  define MAXSTACK 6000
 #endif
 static const int n_keyword_lists = 9;
 static KeywordToken *reserved_keywords[] = {

Tools/peg_generator/pegen/c_generator.py

@@ -44,7 +44,7 @@ EXTENSION_PREFIX = """\
 #    define MAXSTACK 4000
 #  endif
 #else
-#  define MAXSTACK 4000
+#  define MAXSTACK 6000
 #endif
 
 """