Initial commit of Python queries and QL libraries.

python/ql/src/Classes/ShouldBeContextManager.ql

@@ -0,0 +1,19 @@
+/**
+ * @name Class should be a context manager
+ * @description Making a class a context manager allows instances to be used in a 'with' statement.
+ *              This improves resource handling and code readability.
+ * @kind problem
+ * @tags maintainability
+ *       readability
+ *       convention
+ * @problem.severity recommendation
+ * @sub-severity high
+ * @precision medium
+ * @id py/should-be-context-manager
+ */
+
+import python
+
+from ClassObject c
+where not c.isC() and not c.isContextManager() and exists(c.declaredAttribute("__del__"))
+select c, "Class " + c.getName() + " implements __del__ (presumably to release some resource). Consider making it a context manager."