SONARPY-1345 Fix stack overflow when a nested class inherits from a c…

…lass with the same name (#1498)

python-frontend/src/main/java/org/sonar/python/tree/TreeUtils.java

@@ -22,6 +22,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.EnumSet;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
@@ -145,21 +146,22 @@ public static ClassSymbol getClassSymbolFromDef(@Nullable ClassDef classDef) {
   }
 
   public static List<String> getParentClassesFQN(ClassDef classDef) {
-    return getParentClasses(TreeUtils.getClassSymbolFromDef(classDef)).stream()
+    return getParentClasses(TreeUtils.getClassSymbolFromDef(classDef), new HashSet<>()).stream()
       .map(Symbol::fullyQualifiedName)
       .filter(Objects::nonNull)
       .collect(Collectors.toList());
   }
 
-  private static List<Symbol> getParentClasses(@Nullable ClassSymbol classSymbol) {
+  private static List<Symbol> getParentClasses(@Nullable ClassSymbol classSymbol, Set<ClassSymbol> visitedSymbols) {
     List<Symbol> superClasses = new ArrayList<>();
-    if (classSymbol == null) {
+    if (classSymbol == null || visitedSymbols.contains(classSymbol)) {
       return superClasses;
     }
+    visitedSymbols.add(classSymbol);
     for (Symbol symbol : classSymbol.superClasses()) {
       superClasses.add(symbol);
       if (symbol instanceof ClassSymbol) {
-        superClasses.addAll(getParentClasses((ClassSymbol) symbol));
+        superClasses.addAll(getParentClasses((ClassSymbol) symbol, visitedSymbols));
       }
     }
     return superClasses;

python-frontend/src/test/java/org/sonar/python/semantic/ProjectLevelSymbolTableTest.java

@@ -38,15 +38,18 @@
 import org.sonar.plugins.python.api.symbols.Symbol;
 import org.sonar.plugins.python.api.symbols.Usage;
 import org.sonar.plugins.python.api.tree.CallExpression;
+import org.sonar.plugins.python.api.tree.ClassDef;
 import org.sonar.plugins.python.api.tree.FileInput;
 import org.sonar.plugins.python.api.tree.FunctionDef;
 import org.sonar.plugins.python.api.tree.ImportFrom;
 import org.sonar.plugins.python.api.tree.QualifiedExpression;
+import org.sonar.plugins.python.api.tree.Statement;
 import org.sonar.plugins.python.api.tree.Tree;
 import org.sonar.python.PythonTestUtils;
 import org.sonar.python.index.Descriptor;
 import org.sonar.python.index.DescriptorUtils;
 import org.sonar.python.index.VariableDescriptor;
+import org.sonar.python.tree.TreeUtils;
 import org.sonar.python.types.DeclaredType;
 import org.sonar.python.types.InferredTypes;
 
@@ -697,7 +700,25 @@ public void class_having_itself_as_superclass_should_not_trigger_error() {
     FileInput fileInput = parseWithoutSymbols("class A(A): pass");
     Set<Symbol> globalSymbols = globalSymbols(fileInput, "mod");
     ClassSymbol a = (ClassSymbol) globalSymbols.iterator().next();
+    // SONARPY-1350: The parent "A" is not yet defined  at the time it is read, so this is actually not correct
     assertThat(a.superClasses()).containsExactly(a);
+    ClassDef classDef = (ClassDef) fileInput.statements().statements().get(0);
+    assertThat(TreeUtils.getParentClassesFQN(classDef)).containsExactly("mod.mod.A");
+  }
+
+
+  @Test
+  public void class_having_another_class_with_same_name_should_not_trigger_error() {
+    FileInput fileInput = parseWithoutSymbols(
+      "from external import B",
+      "class A:",
+      "  class B(B): pass"
+    );
+    globalSymbols(fileInput, "mod");
+    ClassDef outerClassDef = (ClassDef) fileInput.statements().statements().get(1);
+    ClassDef innerClassDef = (ClassDef) outerClassDef.body().statements().get(0);
+    // SONARPY-1350: Parent should be external.B
+    assertThat(TreeUtils.getParentClassesFQN(innerClassDef)).containsExactly("mod.mod.A.B");
   }
 
   @Test