SONARPY-2809 Make LazyType resolution thread safe (#213)

GitOrigin-RevId: 54a5d3b4c2f95c64ce859d621c715902ee54b735

Author: maksim-grebeniuk-sonarsource

python-frontend/src/main/java/org/sonar/python/semantic/v2/LazyTypesContext.java

@@ -18,6 +18,7 @@
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import org.sonar.python.types.v2.LazyType;
 import org.sonar.python.types.v2.LazyTypeWrapper;
 import org.sonar.plugins.python.api.types.v2.PythonType;
@@ -28,7 +29,7 @@ public class LazyTypesContext {
   private final TypeTable typeTable;
 
   public LazyTypesContext(ProjectLevelTypeTable typeTable) {
-    this.lazyTypes = new HashMap<>();
+    this.lazyTypes = new ConcurrentHashMap<>();
     this.typeTable = typeTable;
   }
 
@@ -37,12 +38,7 @@ public TypeWrapper getOrCreateLazyTypeWrapper(String importPath) {
   }
 
   public LazyType getOrCreateLazyType(String importPath) {
-    if (lazyTypes.containsKey(importPath)) {
-      return lazyTypes.get(importPath);
-    }
-    var lazyType = new LazyType(importPath, this);
-    lazyTypes.put(importPath, lazyType);
-    return lazyType;
+    return lazyTypes.computeIfAbsent(importPath, ip -> new LazyType(ip, this));
   }
 
   public PythonType resolveLazyType(LazyType lazyType) {

python-frontend/src/main/java/org/sonar/python/semantic/v2/converter/FunctionDescriptorToPythonTypeConverter.java

@@ -17,6 +17,7 @@
 package org.sonar.python.semantic.v2.converter;
 
 import java.util.List;
+import java.util.Objects;
 import java.util.Optional;
 import org.sonar.python.index.Descriptor;
 import org.sonar.python.index.FunctionDescriptor;
@@ -49,6 +50,7 @@ public PythonType convert(ConversionContext ctx, FunctionDescriptor from) {
 
     var decorators = from.decorators()
       .stream()
+      .filter(Objects::nonNull) // SONARPY-2813 needs to be done to fix the null decorators
       .map(ctx.lazyTypesContext()::getOrCreateLazyType)
       .map(TypeWrapper::of)
       .toList();

python-frontend/src/main/java/org/sonar/python/types/v2/LazyType.java

@@ -16,9 +16,10 @@
  */
 package org.sonar.python.types.v2;
 
-import java.util.ArrayDeque;
+import java.util.ArrayList;
 import java.util.Optional;
-import java.util.Queue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
 import java.util.function.Consumer;
 import org.sonar.plugins.python.api.LocationInFile;
 import org.sonar.plugins.python.api.types.v2.PythonType;
@@ -29,14 +30,14 @@
 public class LazyType implements PythonType, ResolvableType {
 
   String importPath;
-  private final Queue<Consumer<PythonType>> consumers;
+  private final BlockingQueue<Consumer<PythonType>> consumers;
   private final LazyTypesContext lazyTypesContext;
   private static final String INTERACTION_MESSAGE = "Lazy types should not be interacted with.";
 
   public LazyType(String importPath, LazyTypesContext lazyTypesContext) {
     this.importPath = importPath;
     this.lazyTypesContext = lazyTypesContext;
-    consumers = new ArrayDeque<>();
+    consumers = new LinkedBlockingQueue<>();
   }
 
   public String importPath() {
@@ -49,18 +50,22 @@ public LazyType addConsumer(Consumer<PythonType> consumer) {
   }
 
   public LazyType resolve(PythonType type) {
-    consumers.forEach(c -> c.accept(type));
-    consumers.clear();
+    notifyConsumers(type);
     return this;
   }
 
-  public PythonType resolve() {
+  public synchronized PythonType resolve() {
     PythonType resolvedType = lazyTypesContext.resolveLazyType(this);
-    consumers.forEach(c -> c.accept(resolvedType));
-    consumers.clear();
+    notifyConsumers(resolvedType);
     return resolvedType;
   }
 
+  private void notifyConsumers(PythonType type) {
+    var toNotify = new ArrayList<Consumer<PythonType>>();
+    consumers.drainTo(toNotify);
+    toNotify.forEach(c -> c.accept(type));
+  }
+
   @Override
   public PythonType unwrappedType() {
     throw new IllegalStateException(INTERACTION_MESSAGE);