#703: Fix/test yaml anchors and merge

By: Wolf2323 <gabrielpatrikurban@gmail.com>

paper-api/src/main/java/org/bukkit/configuration/file/YamlConfiguration.java

@@ -141,6 +141,7 @@ public class YamlConfiguration extends FileConfiguration {
     }
 
     private void fromNodeTree(@NotNull MappingNode input, @NotNull ConfigurationSection section) {
+        constructor.flattenMapping(input);
         for (NodeTuple nodeTuple : input.getValue()) {
             ScalarNode key = (ScalarNode) nodeTuple.getKeyNode();
             String keyString = key.getValue();

paper-api/src/main/java/org/bukkit/configuration/file/YamlConstructor.java

@@ -7,6 +7,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.yaml.snakeyaml.constructor.SafeConstructor;
 import org.yaml.snakeyaml.error.YAMLException;
+import org.yaml.snakeyaml.nodes.MappingNode;
 import org.yaml.snakeyaml.nodes.Node;
 import org.yaml.snakeyaml.nodes.Tag;
 
@@ -16,6 +17,11 @@ public class YamlConstructor extends SafeConstructor {
         this.yamlConstructors.put(Tag.MAP, new ConstructCustomObject());
     }
 
+    @Override
+    public void flattenMapping(@NotNull final MappingNode node) {
+        super.flattenMapping(node);
+    }
+
     @NotNull
     public Object construct(@NotNull Node node) {
         return constructObject(node);

paper-api/src/test/java/org/bukkit/configuration/file/YamlConfigurationTest.java

@@ -4,6 +4,7 @@ import static org.junit.Assert.*;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import org.bukkit.configuration.InvalidConfigurationException;
 import org.junit.Test;
 
 public class YamlConfigurationTest extends FileConfigurationTest {
@@ -89,4 +90,58 @@ public class YamlConfigurationTest extends FileConfigurationTest {
 
         assertEquals(expected, result);
     }
+
+    @Test
+    public void testAnchorNode() throws InvalidConfigurationException {
+        YamlConfiguration config = getConfig();
+        String content = "effects:\n"
+                + "  eff1: &novaEarth\n"
+                + "    position: special\n"
+                + "    effect: nova\n"
+                + "  eff2: *novaEarth\n"
+                + "  eff3: *novaEarth";
+        config.loadFromString(content);
+
+        String expected = "effects:\n"
+                + "  eff1:\n"
+                + "    position: special\n"
+                + "    effect: nova\n"
+                + "  eff2:\n"
+                + "    position: special\n"
+                + "    effect: nova\n"
+                + "  eff3:\n"
+                + "    position: special\n"
+                + "    effect: nova\n";
+        assertEquals(expected, config.saveToString());
+    }
+
+    @Test
+    public void testMergeNode() throws InvalidConfigurationException {
+        YamlConfiguration config = getConfig();
+        String content = "effects:\n"
+                + "  eff1: &novaEarth\n"
+                + "    position: special\n"
+                + "    effect: nova\n"
+                + "  eff2: \n"
+                + "    <<: *novaEarth\n"
+                + "    height-offset: 0\n"
+                + "  eff3: \n"
+                + "    <<: *novaEarth\n"
+                + "    height-offset: 2";
+        config.loadFromString(content);
+
+        String expected = "effects:\n"
+                + "  eff1:\n"
+                + "    position: special\n"
+                + "    effect: nova\n"
+                + "  eff2:\n"
+                + "    position: special\n"
+                + "    effect: nova\n"
+                + "    height-offset: 0\n"
+                + "  eff3:\n"
+                + "    position: special\n"
+                + "    effect: nova\n"
+                + "    height-offset: 2\n";
+        assertEquals(expected, config.saveToString());
+    }
 }