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backend/app/dataset/rules/python/logic_operator.py

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+"""AST-level logical operator misuse injection for Python."""
+
+import ast
+from typing import Optional
+
+from app.dataset.rules.base import Mutation, MutationRule
+
+
+class LogicOperatorRule(MutationRule):
+    """Swap `and` with `or` in a boolean expression.
+
+    Uses `ast` to locate a BoolOp using `And` and replaces it with `Or`,
+    preserving exact source position via line replacement.
+    """
+
+    name = "logic_operator"
+    language = "python"
+    defect_type = "logic_operator_misuse"
+
+    def detect_and_mutate(self, source: str, filename: str = "") -> Optional[Mutation]:
+        try:
+            tree = ast.parse(source)
+        except SyntaxError:
+            return None
+
+        for node in ast.walk(tree):
+            if isinstance(node, ast.BoolOp) and isinstance(node.op, ast.And):
+                line_no = node.lineno
+                lines = source.splitlines(keepends=True)
+                line = lines[line_no - 1]
+                mutated_line = line.replace(" and ", " or ", 1)
+                if mutated_line == line:
+                    continue
+                mutated = "".join(lines[:line_no - 1] + [mutated_line] + lines[line_no:])
+                return Mutation(
+                    defect_type=self.defect_type,
+                    language=self.language,
+                    line_start=line_no,
+                    line_end=getattr(node, "end_lineno", line_no) or line_no,
+                    mutated_source=mutated,
+                    reference_fix="Restore the original `and` operator for correct short-circuit logic.",
+                    description="Replaced boolean `and` with `or`.",
+                )
+        return None