Add ACN Mutator (assert(...) Condition Negation)

slither/tools/mutator/mutators/ACN.py

@@ -0,0 +1,63 @@
+from slither.core.declarations.solidity_variables import SolidityFunction
+from slither.core.expressions.call_expression import CallExpression
+from slither.core.expressions.identifier import Identifier
+from slither.core.expressions.unary_operation import UnaryOperation, UnaryOperationType
+from slither.tools.mutator.mutators.abstract_mutator import AbstractMutator
+from slither.tools.mutator.utils.patch import create_patch_with_line
+
+
+class ACN(AbstractMutator):
+    NAME = "ACN"
+    HELP = "Assert Condition Negation"
+
+    def _mutate(self) -> dict:
+        result: dict = {}
+
+        for function in self.contract.functions_and_modifiers_declared:
+            if not self.should_mutate_function(function):
+                continue
+
+            for node in function.nodes:
+                if not self.should_mutate_node(node):
+                    continue
+
+                try:
+                    expression = node.expression
+                except AttributeError:
+                    continue
+
+                if not isinstance(expression, CallExpression):
+                    continue
+
+                if not isinstance(expression.called, Identifier):
+                    continue
+
+                called = expression.called.value
+                if not isinstance(called, SolidityFunction):
+                    continue
+
+                if not called.name.startswith("assert("):
+                    continue
+
+                if not expression.arguments:
+                    continue
+
+                condition = expression.arguments[0]
+
+                start = condition.source_mapping.start
+                stop = start + condition.source_mapping.length
+                old_str = condition.source_mapping.content
+                line_no = condition.source_mapping.lines[0]
+                new_str = f"!({old_str})"
+
+                create_patch_with_line(
+                    result,
+                    self.in_file,
+                    start,
+                    stop,
+                    old_str,
+                    new_str,
+                    line_no,
+                )
+
+        return result

slither/tools/mutator/mutators/all_mutators.py

@@ -11,5 +11,6 @@
 from slither.tools.mutator.mutators.FHR import FHR  # severity medium
 from slither.tools.mutator.mutators.MIA import MIA  # severity medium
 from slither.tools.mutator.mutators.ROR import ROR  # severity medium
+from slither.tools.mutator.mutators.ACN import ACN  # severity medium
 from slither.tools.mutator.mutators.RR import RR  # severity high
 from slither.tools.mutator.mutators.CR import CR  # severity high

tests/tools/mutator/test_data/test_source_unit/src/Counter.sol

@@ -11,6 +11,7 @@ contract Counter {
     }
 
     function setNumber(uint256 newNumber) public {
+        assert(newNumber != 7);
         number = newNumber;
     }
 

tests/tools/mutator/test_mutator.py

@@ -14,6 +14,7 @@
 from slither.tools.mutator.utils.file_handling import get_sol_file_list, backup_source_file
 from slither.utils.function import get_function_id
 from slither.tools.mutator.mutators.RR import RR
+from slither.tools.mutator.mutators.ACN import ACN
 
 
 TEST_DATA_DIR = Path(__file__).resolve().parent / "test_data"
@@ -283,3 +284,34 @@ def test_should_mutate_function_includes_modifier(solc_binary_path):
         for mod in contract.modifiers:
             if mod.name == "onlyOwner":
                 assert mutator.should_mutate_function(mod) is True
+
+
+def test_acn_mutates_assert_condition(solc_binary_path):
+    solc_path = solc_binary_path("0.8.15")
+    file_path = (TEST_DATA_DIR / "test_source_unit" / "src" / "Counter.sol").as_posix()
+    sl = Slither(file_path, solc=solc_path, compile_force_framework="solc")
+    contract = next(c for c in sl.contracts if c.name == "Counter")
+
+    with tempfile.TemporaryDirectory() as tmpdir:
+        mutator = ACN(
+            sl.compilation_units[0],
+            timeout=30,
+            testing_command="true",
+            testing_directory=None,
+            contract_instance=contract,
+            solc_remappings=None,
+            verbose=False,
+            output_folder=Path(tmpdir),
+            dont_mutate_line=[],
+            target_selectors=None,
+            target_modifiers=None,
+        )
+
+        patches = mutator._mutate()
+        assert "patches" in patches
+        assert file_path in patches["patches"]
+
+        assert any(
+            patch["old_string"] == "newNumber != 7" and patch["new_string"] == "!(newNumber != 7)"
+            for patch in patches["patches"][file_path]
+        )