SONARJAVA-6798 Collect dependencies from implicit single-constructor injection

java-frontend/src/main/java/org/sonar/java/model/springcontext/BeanDefinitionGatherer.java

@@ -306,21 +306,27 @@ private void collectBeanMethod(MethodTree method, String pkg) {
 
   private static Map<String, Set<String>> collectAutowiredDependencies(ClassTree classTree) {
     Map<String, Set<String>> deps = new LinkedHashMap<>();
+    List<MethodTree> unannotatedConstructors = new ArrayList<>();
     for (Tree member : classTree.members()) {
       if (member instanceof VariableTree field) {
         if (field.symbol().metadata().isAnnotatedWith(SpringUtils.AUTOWIRED_ANNOTATION)) {
           String typeFqn = field.symbol().type().fullyQualifiedName();
           String name = dependencyKey(field.simpleName().name(), extractQualifier(field.symbol().metadata()));
           deps.computeIfAbsent(typeFqn, k -> new LinkedHashSet<>()).add(name);
         }
-      } else if (member.is(Tree.Kind.CONSTRUCTOR, Tree.Kind.METHOD)) {
-        MethodTree method = (MethodTree) member;
+      } else if (member instanceof MethodTree method) {
         if (method.symbol().metadata().isAnnotatedWith(SpringUtils.AUTOWIRED_ANNOTATION)) {
           parameterDependencies(method).forEach((type, names) ->
             deps.computeIfAbsent(type, k -> new LinkedHashSet<>()).addAll(names));
+        } else if (method.is(Tree.Kind.CONSTRUCTOR)) {
+          unannotatedConstructors.add(method);
         }
       }
     }
+    if (deps.isEmpty() && unannotatedConstructors.size() == 1) {
+      parameterDependencies(unannotatedConstructors.get(0)).forEach((type, names) ->
+        deps.computeIfAbsent(type, k -> new LinkedHashSet<>()).addAll(names));
+    }
     return deps;
   }
 

java-frontend/src/test/files/springcontext/MultipleConstructorsNoDependencies.java

@@ -0,0 +1,22 @@
+package checks.spring.context;
+
+import org.springframework.context.ApplicationContext;
+import org.springframework.core.env.Environment;
+import org.springframework.stereotype.Component;
+
+@Component
+class MultipleConstructorsNoDependencies {
+
+  private final ApplicationContext applicationContext;
+  private final Environment environment;
+
+  MultipleConstructorsNoDependencies(ApplicationContext applicationContext) {
+    this.applicationContext = applicationContext;
+    this.environment = null;
+  }
+
+  MultipleConstructorsNoDependencies(ApplicationContext applicationContext, Environment environment) {
+    this.applicationContext = applicationContext;
+    this.environment = environment;
+  }
+}

java-frontend/src/test/files/springcontext/SingleConstructorDependencies.java

@@ -0,0 +1,17 @@
+package checks.spring.context;
+
+import org.springframework.context.ApplicationContext;
+import org.springframework.core.env.Environment;
+import org.springframework.stereotype.Component;
+
+@Component
+class SingleConstructorDependencies {
+
+  private final ApplicationContext applicationContext;
+  private final Environment environment;
+
+  SingleConstructorDependencies(ApplicationContext applicationContext, Environment environment) {
+    this.applicationContext = applicationContext;
+    this.environment = environment;
+  }
+}

java-frontend/src/test/java/org/sonar/java/model/springcontext/BeanDefinitionGathererTest.java

@@ -201,10 +201,22 @@ static Stream<Arguments> dependencyCollectionArguments() {
     return Stream.of(
       Arguments.of("src/test/files/springcontext/AutowiredDependencies.java", "autowiredDependencies"),
       Arguments.of("src/test/files/springcontext/AutowiredConstructorDependencies.java", "autowiredConstructorDependencies"),
-      Arguments.of("src/test/files/springcontext/BeanMethodWithDependencies.java", "myBean")
+      Arguments.of("src/test/files/springcontext/BeanMethodWithDependencies.java",    "myBean"),
+      Arguments.of("src/test/files/springcontext/SingleConstructorDependencies.java", "singleConstructorDependencies")
     );
   }
 
+  // ---- Implicit single-constructor injection --------------------------------
+
+  @Test
+  void multiple_constructors_without_autowired_yields_no_dependencies() {
+    scan("src/test/files/springcontext/MultipleConstructorsNoDependencies.java");
+
+    var beans = model.getBeanDefinitionRegistry().getByName("multipleConstructorsNoDependencies");
+    assertThat(beans).hasSize(1);
+    assertThat(beans.get(0).getDependingBeans()).isEmpty();
+  }
+
   // ---- @Qualifier handling --------------------------------------------------
 
   @ParameterizedTest(name = "{0}")