Fixed Issue [#40](#40)

Fixed badly-formatted dates in the changelog
Added ability for pySHACL to track and monitor its evaluation path during validation
- This allows for the validator to detect two different scenarios:
  - A recursive shape has triggered an infinitely-recursive validation, back out
  - Evaluation Path too deep (error generated, prevents python recursion depth errors)
Added a test for Issue #40

pyshacl/__init__.py

@@ -3,6 +3,6 @@
 from pyshacl.validate import validate, Validator
 
 # version compliant with https://www.python.org/dev/peps/pep-0440/
-__version__ = '0.11.3.post1'
+__version__ = '0.11.4'
 
 __all__ = ['validate', 'Validator', '__version__']

pyshacl/cli.py

@@ -43,6 +43,7 @@
 parser.add_argument('-o', '--output', dest='output', nargs='?', type=argparse.FileType('w'),
                     help='Send output to a file (defaults to stdout).',
                     default=sys.stdout)
+#parser.add_argument('-h', '--help', action="help", help='Show this help text.')
 
 
 def main():

pyshacl/constraints/constraint_component.py

@@ -38,9 +38,36 @@ def shacl_constraint_class(cls):
         return NotImplementedError()  # pragma: no cover
 
     @abc.abstractmethod
-    def evaluate(self, target_graph, focus_value_nodes):
+    def evaluate(self, target_graph, focus_value_nodes, _evaluation_path):
         return NotImplementedError()  # pragma: no cover
 
+    def __str__(self):
+        c_name = str(self.__class__.__name__)
+        shape_id = str(self.shape)
+        return "<{} on {}>".format(c_name, shape_id)
+
+    def recursion_triggers(self, _evaluation_path):
+        shape = self.shape
+        eval_length = len(_evaluation_path)
+        maybe_recursive = []
+        if eval_length >= 6:
+            _shape, _self = _evaluation_path[eval_length - 2:]
+            if _shape is not shape or _self is not self:
+                raise RuntimeError("Bad evaluation path construction")
+            seen_before = [i for i, x in enumerate(_evaluation_path[:eval_length-2]) if x is shape] #_evaluation_path.index(shape, 0, eval_length - 2)
+            for s in seen_before:
+                for i, p in enumerate(_evaluation_path[s + 1:-2]):
+                    if isinstance(p, ConstraintComponent):
+                        if p.shape is shape and p.__class__ == self.__class__:
+                            try:
+                                next_shape = _evaluation_path[s + 1 + i + 1]
+                                maybe_recursive.append(next_shape)
+                            except IndexError:
+                                pass
+                        break
+        return maybe_recursive
+
+
     def make_v_result_description(self, datagraph, focus_node, severity, value_node=None, result_path=None,
                                   constraint_component=None, source_constraint=None, extra_messages=None):
         """

pyshacl/constraints/core/cardinality_constraints.py

@@ -64,7 +64,7 @@ def constraint_name(cls):
     def shacl_constraint_class(cls):
         return SH_MinCountConstraintComponent
 
-    def evaluate(self, target_graph, focus_value_nodes):
+    def evaluate(self, target_graph, focus_value_nodes, _evaluation_path):
         """
 
         :type focus_value_nodes: dict
@@ -132,7 +132,7 @@ def constraint_name(cls):
     def shacl_constraint_class(cls):
         return SH_MaxCountConstraintComponent
 
-    def evaluate(self, target_graph, focus_value_nodes):
+    def evaluate(self, target_graph, focus_value_nodes, _evaluation_path):
         """
 
         :type focus_value_nodes: dict