first commit

backend/app/dataset/rules/java/resource_leak.py

@@ -0,0 +1,50 @@
+"""AST-level resource leak injection for Java using javalang."""
+
+from typing import Optional
+
+import javalang
+
+from app.dataset.rules.base import Mutation, MutationRule
+
+
+class JavaResourceLeakRule(MutationRule):
+    """Replace try-with-resources with a plain try block, leaking the resource.
+
+    Uses `javalang` to locate a try-with-resources statement and removes the
+    resource specification, leaving the stream unclosed.
+    """
+
+    name = "java_resource_leak"
+    language = "java"
+    defect_type = "resource_not_closed"
+
+    def detect_and_mutate(self, source: str, filename: str = "") -> Optional[Mutation]:
+        try:
+            tree = javalang.parse.parse(source)
+        except Exception:
+            return None
+
+        for path, node in tree:
+            if not isinstance(node, javalang.tree.TryStatement):
+                continue
+            if not node.resources:
+                continue
+            pos = node.position
+            if not pos:
+                continue
+            lines = source.splitlines(keepends=True)
+            start = pos.line
+            # Find the resource clause line e.g. try (BufferedReader br = ...)
+            resource_line = lines[start - 1]
+            new_header = resource_line.split("(", 1)[0].rstrip() + " {\n"
+            mutated = "".join(lines[: start - 1] + [new_header] + lines[start:])
+            return Mutation(
+                defect_type=self.defect_type,
+                language=self.language,
+                line_start=start,
+                line_end=start,
+                mutated_source=mutated,
+                reference_fix="Use try-with-resources or explicitly close the stream in finally.",
+                description="Removed try-with-resources, leaking the acquired resource.",
+            )
+        return None