limits

Author: mpharrigan

qualtran/l1/_eval.py

@@ -47,6 +47,8 @@ def eval_carg_nodes(
         args: The evaluated positional arguments
         kwargs: The evaluated keyword arguments
     """
+    if len(cargs) > 1_000 and safe:
+        raise ValueError("Too many arguments for safe=True loading.")
     args: List[Any] = []
     kwargs: Dict[str, Any] = {}
     kwarg_only = False
@@ -153,6 +155,8 @@ def eval_cvalue_node(node: CValueNode, *, safe: bool = True) -> Any:
 
     # Recurse on tuples
     if isinstance(node, TupleNode):
+        if len(node.items) > 1_000 and safe:
+            raise ValueError("Too many elements for safe=True tuple.")
         return tuple(eval_cvalue_node(n, safe=safe) for n in node.items)
 
     # Objects

qualtran/l1/_eval_test.py

@@ -208,3 +208,17 @@ def test_imported_bloq_class():
 def test_eval_cvalue_node_type_error():
     with pytest.raises(TypeError, match="Unknown AST node type"):
         eval_cvalue_node("just a string")  # type: ignore[arg-type]
+
+
+def test_too_many_args():
+    node = CObjectNode(name='Test', cargs=[CArgNode(None, LiteralNode(5))] * 1_001)
+
+    with pytest.raises(ValueError, match=r'Too many.*'):
+        _ = eval_cvalue_node(node, safe=True)
+
+
+def test_too_many_values():
+    node = TupleNode([LiteralNode(5)] * 1_001)
+
+    with pytest.raises(ValueError, match=r'Too many.*'):
+        _ = eval_cvalue_node(node, safe=True)

qualtran/l1/_parse_test.py

@@ -13,6 +13,7 @@
 #  limitations under the License.
 
 import io
+import sys
 
 import pytest
 
@@ -216,3 +217,28 @@ def test_parse_cvalue_cobject():
     node = parser.parse_cvalue()
     assert isinstance(node, CObjectNode)
     assert node.name == 'MyBloq'
+
+
+def test_parse_nested():
+    from qualtran.l1._eval import eval_cvalue_node
+
+    n = 100
+    str = '(' * n + '5,' + ')' * n
+    tokens = tokenize(str)
+    parser = QualtranL1Parser(tokens)
+    ast = parser.parse_cvalue()
+    result = eval_cvalue_node(ast)
+
+    should_be = 5
+    for i in range(n):
+        should_be = (should_be,)
+    assert result == should_be
+
+
+def test_parse_too_nested():
+    n = sys.getrecursionlimit() + 1
+    str = '(' * n + '5,' + ')' * n
+    tokens = tokenize(str)
+    parser = QualtranL1Parser(tokens)
+    with pytest.raises(RecursionError):
+        ast = parser.parse_cvalue()