fix(yaml): Preserve empty elements, increase max line length

Author: zml2008

format/yaml/src/main/java/org/spongepowered/configurate/yaml/YamlConfigurationLoader.java

@@ -172,6 +172,8 @@ public final class YamlConfigurationLoader extends AbstractConfigurationLoader<C
             Boolean.class, Integer.class, Long.class, BigInteger.class, Double.class, // numeric
             byte[].class, String.class, Date.class, java.sql.Date.class, Timestamp.class); // complex types
 
+    private static final int DEFAULT_LINE_LENGTH = 150;
+
     /**
      * Creates a new {@link YamlConfigurationLoader} builder.
      *
@@ -328,6 +330,7 @@ private YamlConfigurationLoader(final Builder builder) {
         opts.setProcessComments(builder.commentsEnabled());
         opts.setIndentWithIndicator(true);
         opts.setIndicatorIndent(builder.indent());
+        opts.setWidth(DEFAULT_LINE_LENGTH);
         this.defaultNodeStyle = builder.nodeStyle();
         this.options = opts;
         this.loader = new LoaderOptions()
@@ -339,7 +342,6 @@ private YamlConfigurationLoader(final Builder builder) {
 
     @Override
     protected void loadInternal(final CommentedConfigurationNode node, final BufferedReader reader) throws ParsingException {
-        // Match the superclass implementation, except we substitute our own scanner implementation
         final YamlParserComposer parser = new YamlParserComposer(new StreamReader(reader), this.loader, Yaml11Tags.REPOSITORY);
         parser.singleDocumentStream(node);
     }

format/yaml/src/main/java/org/spongepowered/configurate/yaml/YamlParserComposer.java

@@ -536,7 +536,9 @@ private Scalar() {
                     // todo: maybe throw here?
                     tag = Yaml11Tags.STR;
                 }
-                head.node.raw(((Tag.Scalar<?>) tag).fromString(scalar.getValue()));
+                if (!Yaml11Tags.NULL.equals(tag)) { // we don't want to nuke node data with null values
+                    head.node.raw(((Tag.Scalar<?>) tag).fromString(scalar.getValue()));
+                }
             }
             self.applyComment(comments, head.node);
             head.node.hint(YamlConfigurationLoader.TAG, tag);

format/yaml/src/main/java/org/spongepowered/configurate/yaml/YamlVisitor.java

@@ -109,6 +109,19 @@ public void enterNode(final ConfigurationNode node, final State state) throws Co
             state.mapKeyHolder.raw(node.key());
             state.mapKeyHolder.visit(this, state);
         }
+
+        // detect null value
+        if (node.empty() && node.raw() == null) {
+            state.emit(new ScalarEvent(
+                this.anchor(node),
+                null,
+                new ImplicitTuple(true, false),
+                "",
+                null,
+                null,
+                DumperOptions.ScalarStyle.PLAIN
+            ));
+        }
     }
 
     @Override