fix: incorrect copying behavior when copying view containers, optimiz…

…ation to prevent graph traversal when copying already-immutable containers (or immutable views)

buildSrc/src/main/groovy/ethylene.library-conventions.gradle

@@ -6,7 +6,7 @@ plugins {
 }
 
 group 'com.github.steanky'
-version '0.26.0'
+version '0.26.1'
 
 publishing {
     publications {

ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/ConfigContainers.java

@@ -58,6 +58,10 @@ final class ConfigContainers {
      * @return an immutable copy of the original
      */
     static @NotNull ConfigContainer immutableCopy(@NotNull ConfigContainer original) {
+        if (original instanceof Immutable) {
+            return original;
+        }
+
         return Graph.process(original, (ConfigElement node) -> {
             ConfigContainer configContainer = node.asContainer();
             Collection<ConfigEntry> entryCollection = configContainer.entryCollection();
@@ -111,11 +115,16 @@ public void accept(String s, ConfigElement element, boolean circular) {
      * @return an immutable view of the provided container
      */
     static @NotNull ConfigContainer immutableView(@NotNull ConfigContainer container) {
+        if (container instanceof ImmutableView) {
+            return container;
+        }
+
         return Graph.process(container, (ConfigElement node) -> {
             ConfigContainer configContainer = node.asContainer();
             Collection<ConfigEntry> entryCollection = configContainer.entryCollection();
 
-            if (configContainer instanceof Immutable) {
+            // all Immutable are also ImmutableView, so we don't explore those either!
+            if (configContainer instanceof ImmutableView) {
                 return Graph.node(Iterators.iterator(), Graph.output(configContainer, Graph.emptyAccumulator()));
             }
 
@@ -130,7 +139,7 @@ public void accept(String s, ConfigElement element, boolean circular) {
         }, ConfigElement::isContainer, Function.identity(), Graph.Options.TRACK_REFERENCES).asContainer();
     }
 
-    private static class ConfigNodeView extends AbstractConfigNode implements Immutable {
+    private static class ConfigNodeView extends AbstractConfigNode implements ImmutableView {
         private final ConfigNode underlying;
 
         private ConfigNodeView(ConfigNode underlying) {
@@ -191,7 +200,7 @@ public Set<Entry<String, ConfigElement>> entrySet() {
         }
     }
 
-    static final class ConfigListView extends AbstractConfigList implements Immutable, RandomAccess {
+    static final class ConfigListView extends AbstractConfigList implements RandomAccess, ImmutableView {
         private final ConfigList underlying;
 
         private ConfigListView(ConfigList underlying) {

ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/DefaultingConfigList.java

@@ -15,7 +15,7 @@
  *
  * @see ConfigList#defaulting(ConfigList, ConfigList)
  */
-class DefaultingConfigList extends AbstractConfigList implements Immutable, RandomAccess {
+class DefaultingConfigList extends AbstractConfigList implements RandomAccess {
     private final ConfigList base;
     private final ConfigList defaults;
 

ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/DefaultingConfigNode.java

@@ -12,7 +12,7 @@
  *
  * @see ConfigNode#defaulting(ConfigNode, ConfigNode)
  */
-class DefaultingConfigNode extends AbstractConfigNode implements Immutable {
+class DefaultingConfigNode extends AbstractConfigNode {
     private final ConfigNode base;
     private final ConfigNode defaults;
 

ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/Immutable.java

@@ -3,10 +3,11 @@
 /**
  * Marker interface indicating a {@link ConfigContainer} implementation is immutable; i.e. its mutating methods, like
  * {@link ConfigList#add(Object)} or {@link ConfigNode#put(Object, Object)}, will throw an exception if called, and
- * cannot change the container itself. However, the contents may still change if there is an underlying container
- * that is mutable.
+ * cannot change the container itself. Similarly, the reported contents of the container may <i>not</i> change over its
+ * lifetime.
  * <p>
- * Additionally, implementations must ensure that any sub-containers are also immutable.
+ * Implementations must ensure that any sub-containers are also immutable in this way.
+ * @see ImmutableView
  */
-public interface Immutable {
+public interface Immutable extends ImmutableView {
 }

ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/ImmutableView.java

@@ -0,0 +1,11 @@
+package com.github.steanky.ethylene.core.collection;
+
+/**
+ * Marker interface used to indicate that the {@link ConfigContainer} implementation does not support direct
+ * modification. However, it <i>may</i> be modified if a backing container is changed.
+ * <p>
+ * Implementations must ensure that any sub-containers are also immutable in this way.
+ * @see Immutable
+ */
+public interface ImmutableView {
+}