Avoid re-initializing factories that are already initialized. This is necessary because we share the internal factory implementation, which leads to initialize(..) being called multiple times. There are other consequences/quirks of this, but re-initialization is the worst of it.

(cherry-picked into the 6.0 release.)

Author: sameb

core/src/com/google/inject/internal/RealMapBinder.java

@@ -813,6 +813,7 @@ private static final class RealProviderMapProvider<K, V>
       extends RealMapBinderProviderWithDependencies<K, V, Map<K, Provider<V>>> {
     private Map<K, Provider<V>> mapOfProviders;
     private Set<Dependency<?>> dependencies = RealMapBinder.MODULE_DEPENDENCIES;
+    private boolean initialized;
 
     private RealProviderMapProvider(BindingSelection<K, V> bindingSelection) {
       super(bindingSelection);
@@ -825,6 +826,10 @@ public Set<Dependency<?>> getDependencies() {
 
     @Override
     protected void doInitialize(InjectorImpl injector, Errors errors) {
+      if (initialized) {
+        return;
+      }
+      initialized = true;
       ImmutableMap.Builder<K, Provider<V>> mapOfProvidersBuilder = ImmutableMap.builder();
       ImmutableSet.Builder<Dependency<?>> dependenciesBuilder = ImmutableSet.builder();
       for (Map.Entry<K, Binding<V>> entry : bindingSelection.getMapBindings().entrySet()) {
@@ -855,6 +860,8 @@ private static final class RealMapProvider<K, V>
 
     K[] keys;
 
+    private boolean initialized = false;
+
     RealMapProvider(BindingSelection<K, V> bindingSelection) {
       super(bindingSelection);
     }
@@ -865,6 +872,10 @@ BindingSelection<K, V> getBindingSelection() {
 
     @Override
     protected void doInitialize(InjectorImpl injector, Errors errors) throws ErrorsException {
+      if (initialized) {
+        return;
+      }
+      initialized = true;
       @SuppressWarnings("unchecked")
       K[] keysArray = (K[]) new Object[bindingSelection.getMapBindings().size()];
       keys = keysArray;
@@ -1209,6 +1220,7 @@ private static final class RealProviderMultimapProvider<K, V>
         extends RealMultimapBinderProviderWithDependencies<K, V, Map<K, Set<Provider<V>>>> {
       private Map<K, Set<Provider<V>>> multimapOfProviders;
       private Set<Dependency<?>> dependencies = RealMapBinder.MODULE_DEPENDENCIES;
+      private boolean initialized;
 
       private RealProviderMultimapProvider(Key<Map<K, V>> mapKey) {
         super(mapKey);
@@ -1221,6 +1233,10 @@ public Set<Dependency<?>> getDependencies() {
 
       @Override
       protected void doInitialize(InjectorImpl injector, Errors errors) {
+        if (initialized) {
+          return;
+        }
+        initialized = true;
         ImmutableMap.Builder<K, Set<Provider<V>>> multimapOfProvidersBuilder =
             ImmutableMap.builder();
         ImmutableSet.Builder<Dependency<?>> dependenciesBuilder = ImmutableSet.builder();
@@ -1271,6 +1287,8 @@ private PerKeyData(K key, Binding<V>[] bindings, SingleParameterInjector<V>[] in
 
       private PerKeyData<K, V>[] perKeyDatas;
 
+      private boolean initialized = false;
+
       private RealMultimapProvider(Key<Map<K, V>> mapKey) {
         super(mapKey);
       }
@@ -1282,6 +1300,11 @@ public Set<Dependency<?>> getDependencies() {
 
       @Override
       protected void doInitialize(InjectorImpl injector, Errors errors) throws ErrorsException {
+        if (initialized) {
+          return;
+        }
+        initialized = true;
+
         @SuppressWarnings({"unchecked", "rawtypes"})
         PerKeyData<K, V>[] typedPerKeyData =
             new PerKeyData[bindingSelection.getMapBindings().size()];

core/src/com/google/inject/internal/RealOptionalBinder.java

@@ -749,6 +749,7 @@ public int hashCode() {
   private abstract static class RealOptionalBinderProviderWithDependencies<T, P>
       extends InternalProviderInstanceBindingImpl.Factory<P> {
     protected final BindingSelection<T> bindingSelection;
+    private boolean initialized = false;
 
     RealOptionalBinderProviderWithDependencies(BindingSelection<T> bindingSelection) {
       // We need delayed initialization so we can detect jit bindings created by other bindings
@@ -760,8 +761,15 @@ private abstract static class RealOptionalBinderProviderWithDependencies<T, P>
 
     @Override
     final void initialize(InjectorImpl injector, Errors errors) throws ErrorsException {
-      bindingSelection.initialize(injector, errors);
-      doInitialize();
+      if (!initialized) {
+        initialized = true;
+        // Note that bindingSelection.initialize has its own guard, because multiple Factory impls
+        // will delegate to the same bindingSelection (intentionally). The selection has some
+        // initialization, and each factory impl has other initialization that it may additionally
+        // do.
+        bindingSelection.initialize(injector, errors);
+        doInitialize();
+      }
     }
 
     /**