provision to choose to raise error if there are duplicate keys in YAM…

…L - issue EsotericSoftware#57 (EsotericSoftware#60)

* fix for EsotericSoftware#57

* as per review by @NathanSweet on fix for EsotericSoftware#57

* removing the whitespace in the eof

* trying to remove the spaces in files so that git does not complain about

* adding gitattributes file to fix the line endings to clrf (windows style)

* reverting my changes to see if I can redo them to fix the line ending now.. also added a .gitattributes file to keep the line endings to windows style

* Saving files before refreshing line endings

* redone my changes

* correcting the .gitattributes file

* removing .gitattributes

* fix line endings to windows

* fixing line endings to windows format

.gitignore

@@ -5,3 +5,5 @@
 
 bin/
 target/
+.idea
+*.iml

src/com/esotericsoftware/yamlbeans/YamlConfig.java

@@ -47,6 +47,7 @@ public class YamlConfig {
 	boolean beanProperties = true;
 	boolean privateFields;
 	boolean privateConstructors = true;
+	boolean allowDuplicates = true;
 
 	public YamlConfig () {
 		scalarSerializers.put(Date.class, new DateSerializer());
@@ -58,6 +59,11 @@ public YamlConfig () {
 		tagToClass.put("tag:yaml.org,2002:float", Float.class);
 	}
 
+	/** Allows duplicate keys in YAML document. Default is true. */
+	public void setAllowDuplicates (boolean allowDuplicates) {
+		this.allowDuplicates = allowDuplicates;
+	}
+
 	/** Allows the specified tag to be used in YAML instead of the full class name. */
 	public void setClassTag (String tag, Class type) {
 		if (tag == null) throw new IllegalArgumentException("tag cannot be null.");
@@ -264,4 +270,4 @@ static class ConstructorParameters {
 	public static enum WriteClassName {
 		ALWAYS, NEVER, AUTO
 	}
-}
+}

src/com/esotericsoftware/yamlbeans/YamlReader.java

@@ -308,6 +308,7 @@ private Object readValueInternal (Class type, Class elementType, String anchor)
 				throw new YamlReaderException("Error creating object.", ex);
 			}
 			if (anchor != null) anchors.put(anchor, object);
+			ArrayList keys = new ArrayList();
 			while (true) {
 				if (parser.peekNextEvent().type == MAPPING_END) {
 					parser.getNextEvent();
@@ -325,10 +326,18 @@ private Object readValueInternal (Class type, Class elementType, String anchor)
 				if (object instanceof Map) {
 					// Add to map.
 					if (!isExplicitKey) value = readValue(elementType, null, null);
+					if (!config.allowDuplicates && ((Map) object).containsKey(key)) {
+						throw new YamlReaderException("Duplicate key found '" + key + "'");
+					}
 					((Map)object).put(key, value);
 				} else {
 					// Set field on object.
 					try {
+						if (!config.allowDuplicates && keys.contains(key)) {
+							throw new YamlReaderException("Duplicate key found '" + key + "'");
+						}
+						keys.add(key);
+
 						Property property = Beans.getProperty(type, (String)key, config.beanProperties, config.privateFields, config);
 						if (property == null) {
 							if (config.readConfig.ignoreUnknownProperties) continue;
@@ -421,4 +430,4 @@ public static void main (String[] args) throws Exception {
 		YamlReader reader = new YamlReader(new FileReader("test/test.yml"));
 		System.out.println(reader.read());
 	}
-}
+}

test/com/esotericsoftware/yamlbeans/YamlReaderTest.java

@@ -16,6 +16,7 @@
 
 package com.esotericsoftware.yamlbeans;
 
+import java.io.StringReader;
 import java.util.List;
 import java.util.Map;
 
@@ -318,6 +319,48 @@ public void testIgnoreUnknownProperties () {
 		}
 	}
 
+	public void testDuplicateKeysAreNotAllowedIfAllowDuplicateIsSetSo () {
+		String inputWithDuplicates = "a: 1\na: 2\nc: 3";
+		YamlConfig yamlConfig = new YamlConfig();
+		yamlConfig.setAllowDuplicates(false);
+		YamlReader yamlReader = new YamlReader(inputWithDuplicates, yamlConfig);
+		try {
+			yamlReader.read();
+			fail("Duplicates should not have been allowed.");
+		} catch (YamlException e) {
+		}
+
+		String inputWithoutDuplicates = "a: 1\nb: 2\nc: 3";
+		YamlReader yamlReader1 = new YamlReader(inputWithoutDuplicates, yamlConfig);
+		try {
+			yamlReader1.read();
+		} catch (YamlException e) {
+			fail("Duplicates should have been allowed.");
+		}
+	}
+
+	public void testDuplicateKeysAreAllowedIfAllowDuplicateIsSetSo () {
+		String inputWithDuplicates = "a: 1\na: 2\nc: 3";
+		YamlReader yamlReader = new YamlReader(inputWithDuplicates);
+		try {
+			yamlReader.read();
+		} catch (YamlException e) {
+			e.printStackTrace();
+			fail("Duplicates should have been allowed.");
+		}
+
+		String inputWithoutDuplicates = "a: 1\nb: 2\nc: 3";
+		YamlConfig yamlConfig = new YamlConfig();
+		yamlConfig.setAllowDuplicates(false);
+		YamlReader yamlReader1 = new YamlReader(inputWithoutDuplicates, yamlConfig);
+		try {
+			yamlReader1.read();
+		} catch (YamlException e) {
+			e.printStackTrace();
+			fail("Duplicates should have been allowed.");
+		}
+	}
+
 	private static class TypeTagIgnoringReader extends YamlReader {
 
 		public TypeTagIgnoringReader(String yaml) {
@@ -385,4 +428,4 @@ public void testIgnoreTypeTagsEmbedded () throws YamlException {
 		assertEquals(1, lake.fish.size());
 		assertEquals("Walleye", lake.fish.get(0).species);
 	}
-}
+}