[3.9] bpo-25130: Make unit-test about restricting the maximum number of nested blocks...

PyPy and potentially other implementations have different or no
contraints on the number of blocks that can be statically nested. move
the test that checks for this behaviour into a unit test and mark it as
CPython-only..
(cherry picked from commit eb263f9a356f5c5f21b8d5ce20bac92f31c40cad)

Co-authored-by: Carl Friedrich Bolz-Tereick <cfbolz@gmx.de>

diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index f54b09f54f03de3f46868cab64f7314ff9fac7c5..eaa94ea92b5cd2d16f47daaf8f03d924d372e011 100644 (file)
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -531,38 +531,6 @@ isn't, there should be a syntax error.
      ...
    SyntaxError: 'break' outside loop
 
-This raises a SyntaxError, it used to raise a SystemError.
-Context for this change can be found on issue #27514
-
-In 2.5 there was a missing exception and an assert was triggered in a debug
-build.  The number of blocks must be greater than CO_MAXBLOCKS.  SF #1565514
-
-   >>> while 1:
-   ...  while 2:
-   ...   while 3:
-   ...    while 4:
-   ...     while 5:
-   ...      while 6:
-   ...       while 8:
-   ...        while 9:
-   ...         while 10:
-   ...          while 11:
-   ...           while 12:
-   ...            while 13:
-   ...             while 14:
-   ...              while 15:
-   ...               while 16:
-   ...                while 17:
-   ...                 while 18:
-   ...                  while 19:
-   ...                   while 20:
-   ...                    while 21:
-   ...                     while 22:
-   ...                      break
-   Traceback (most recent call last):
-     ...
-   SyntaxError: too many statically nested blocks
-
 Misuse of the nonlocal and global statement can lead to a few unique syntax errors.
 
    >>> def f():
@@ -995,6 +963,42 @@ def func2():
         self._check_error("A.\u03bc\\\n",
                           "unexpected EOF while parsing")
 
+    @support.cpython_only
+    def test_syntax_error_on_deeply_nested_blocks(self):
+        # This raises a SyntaxError, it used to raise a SystemError. Context
+        # for this change can be found on issue #27514
+
+        # In 2.5 there was a missing exception and an assert was triggered in a
+        # debug build.  The number of blocks must be greater than CO_MAXBLOCKS.
+        # SF #1565514
+
+        source = """
+while 1:
+ while 2:
+  while 3:
+   while 4:
+    while 5:
+     while 6:
+      while 8:
+       while 9:
+        while 10:
+         while 11:
+          while 12:
+           while 13:
+            while 14:
+             while 15:
+              while 16:
+               while 17:
+                while 18:
+                 while 19:
+                  while 20:
+                   while 21:
+                    while 22:
+                     break
+"""
+        self._check_error(source, "too many statically nested blocks")
+
+
 def test_main():
     support.run_unittest(SyntaxTestCase)
     from test import test_syntax