SONARPY-744 Avoid FP when subscription object is used inside 'in expressions' (SonarSource#861)

andrea-guarino-sonarsource · web-flow · commit 529b9f378d7e · 2020-08-28T14:10:45.000+02:00
diff --git a/python-checks/src/main/java/org/sonar/python/checks/ConfusingTypeCheckingCheck.java b/python-checks/src/main/java/org/sonar/python/checks/ConfusingTypeCheckingCheck.java
@@ -30,11 +30,13 @@
 import org.sonar.plugins.python.api.symbols.ClassSymbol;
 import org.sonar.plugins.python.api.symbols.Symbol;
 import org.sonar.plugins.python.api.tree.Expression;
+import org.sonar.plugins.python.api.tree.InExpression;
 import org.sonar.plugins.python.api.tree.IsExpression;
 import org.sonar.plugins.python.api.tree.RaiseStatement;
 import org.sonar.plugins.python.api.tree.Token;
 import org.sonar.plugins.python.api.tree.Tree;
 import org.sonar.plugins.python.api.types.InferredType;
+import org.sonar.python.tree.TreeUtils;
 import org.sonar.python.types.InferredTypes;
 import org.sonar.python.types.TypeShed;
 
@@ -110,7 +112,21 @@ public boolean isValidSubscription(Expression subscriptionObject, String require
         // handled by S5644
         return true;
       }
-      return type.declaresMember(requiredMethod);
+      return isUsedInsideInExpression(subscriptionObject) || type.declaresMember(requiredMethod);
+    }
+
+    private static boolean isUsedInsideInExpression(Expression subscriptionObject) {
+      return TreeUtils.getSymbolFromTree(subscriptionObject)
+        .filter(symbol -> symbol.usages().stream().anyMatch(usage -> isRightOperandInExpression(usage.tree())))
+        .isPresent();
+    }
+
+    private static boolean isRightOperandInExpression(Tree tree) {
+      Tree parent = tree.parent();
+      if (parent instanceof InExpression) {
+        return ((InExpression) parent).rightOperand() == tree;
+      }
+      return false;
     }
 
     @Override
diff --git a/python-checks/src/test/resources/checks/confusingTypeChecking/itemOperations.py b/python-checks/src/test/resources/checks/confusingTypeChecking/itemOperations.py
@@ -20,3 +20,15 @@ def f(val: object):
   if not isinstance(val, tuple):
     ...
   val[0]
+
+def checked_with_in(obj: object, other: object, prop):
+  if prop in obj:
+    obj[prop]
+  if other in obj:
+    other[prop] # Noncompliant
+
+def checked_with_not_in(obj: object, prop):
+  if prop not in obj:
+    return
+  obj[prop]
+
