SONARPY-2939 Fix FP for NotImplemented and NotImplementedError (#304)

GitOrigin-RevId: 8526b4fb4f3f34f7efc4a3c4363fbf8c1b7b5965

Author: guillaume-dequenne

python-checks/src/main/java/org/sonar/python/checks/AsyncFunctionNotAsyncCheck.java

@@ -24,6 +24,7 @@
 import org.sonar.plugins.python.api.tree.BaseTreeVisitor;
 import org.sonar.plugins.python.api.tree.ForStatement;
 import org.sonar.plugins.python.api.tree.FunctionDef;
+import org.sonar.plugins.python.api.tree.ReturnStatement;
 import org.sonar.plugins.python.api.tree.Statement;
 import org.sonar.plugins.python.api.tree.StatementList;
 import org.sonar.plugins.python.api.tree.Token;
@@ -33,19 +34,27 @@
 import org.sonar.plugins.python.api.tree.YieldStatement;
 import org.sonar.plugins.python.api.types.v2.ClassType;
 import org.sonar.plugins.python.api.types.v2.FunctionType;
+import org.sonar.plugins.python.api.types.v2.TriBool;
 import org.sonar.python.checks.utils.CheckUtils;
+import org.sonar.python.types.v2.TypeCheckBuilder;
 
 @Rule(key = "S7503")
 public class AsyncFunctionNotAsyncCheck extends PythonSubscriptionCheck {
 
   private static final String MESSAGE = "Use asynchronous features in this function or remove the `async` keyword.";
+  private TypeCheckBuilder notImplementedTypeChecker;
 
   @Override
   public void initialize(Context context) {
-    context.registerSyntaxNodeConsumer(Tree.Kind.FUNCDEF, AsyncFunctionNotAsyncCheck::checkAsyncFunction);
+    context.registerSyntaxNodeConsumer(Tree.Kind.FILE_INPUT, this::setupTypeChecks);
+    context.registerSyntaxNodeConsumer(Tree.Kind.FUNCDEF, this::checkAsyncFunction);
   }
 
-  private static void checkAsyncFunction(SubscriptionContext ctx) {
+  private void setupTypeChecks(SubscriptionContext ctx) {
+    notImplementedTypeChecker = ctx.typeChecker().typeCheckBuilder().isTypeWithName("NotImplemented");
+  }
+
+  private void checkAsyncFunction(SubscriptionContext ctx) {
     FunctionDef functionDef = (FunctionDef) ctx.syntaxNode();
 
     Token asyncKeyword = functionDef.asyncKeyword();
@@ -60,9 +69,9 @@ private static void checkAsyncFunction(SubscriptionContext ctx) {
     }
   }
 
-  private static boolean isException(FunctionDef functionDef) {
+  private boolean isException(FunctionDef functionDef) {
     return CheckUtils.isAbstract(functionDef) ||
-      isEmptyFunction(functionDef.body()) ||
+      isTrivialFunction(functionDef.body()) ||
       isDunderMethod(functionDef) ||
       !functionDef.decorators().isEmpty() ||
       mightBeOverridingMethod(functionDef);
@@ -73,15 +82,20 @@ private static boolean isDunderMethod(FunctionDef functionDef) {
     return methodName.startsWith("__");
   }
 
-  private static boolean isEmptyFunction(StatementList body) {
+  private boolean isTrivialFunction(StatementList body) {
     for (Statement statement : body.statements()) {
-      if (!CheckUtils.isEmptyStatement(statement)) {
+      if (!CheckUtils.isEmptyStatement(statement) && !statement.is(Tree.Kind.RAISE_STMT) && !isReturnNotImplemented(statement)) {
         return false;
       }
     }
     return true;
   }
 
+  private boolean isReturnNotImplemented(Statement statement) {
+    return statement.is(Tree.Kind.RETURN_STMT) &&
+      ((ReturnStatement) statement).expressions().stream().allMatch(e -> notImplementedTypeChecker.check(e.typeV2()) == TriBool.TRUE);
+  }
+
   private static boolean mightBeOverridingMethod(FunctionDef functionDef) {
     FunctionType functionType = (FunctionType) functionDef.name().typeV2();
     return functionType.owner() instanceof ClassType classType && (classType.hasUnresolvedHierarchy() || classType.inheritedMember(functionType.name()).isPresent());

python-checks/src/test/resources/checks/asyncFunctionNotAsync.py

@@ -77,7 +77,11 @@ async def async_generator_with_expression():  # Compliant
     return x
 
 class AsyncClass:
+    async def async_method_without_await_trivial(self):  # Noncompliant
+        return self.some_attribute
+
     async def async_method_without_await(self):  # Noncompliant
+        do_something()
         return self.some_attribute
 
     async def async_method_with_await(self):  # Compliant
@@ -120,6 +124,12 @@ async def __unknown_dunder__(self):
         # Avoid risk of FPs
         pass
 
+    async def not_implemented_error(self):
+        raise NotImplementedError("This method is not implemented")
+
+    async def not_implemented(self):
+        return NotImplemented
+
 class AsyncIterator:
     async def __aiter__(self):
         return self