DATACMNS-867 - Preserve underscores when resolving PropertyPath for PersistentProperties.

Preserve underscores in variable names (eg. String foo_bar) when resolving the actual type information for the property via PropertyPath by quoting (Pattern#quote) the property name.

src/test/java/org/springframework/data/mapping/PropertyPathUnitTests.java

@@ -21,6 +21,7 @@ import static org.springframework.data.mapping.PropertyPath.*;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
+import java.util.regex.Pattern;
 
 import org.junit.Rule;
 import org.junit.Test;
@@ -32,6 +33,7 @@ import org.springframework.data.util.TypeInformation;
  * Unit tests for {@link PropertyPath}.
  * 
  * @author Oliver Gierke
+ * @author Christoph Strobl
  */
 @SuppressWarnings("unused")
 public class PropertyPathUnitTests {
@@ -333,11 +335,22 @@ public class PropertyPathUnitTests {
 		from("userAme", Foo.class);
 	}
 
+	@Test // DATACMNS-867
+	public void preservesUnderscoresForQuotedNames() {
+
+		PropertyPath path = from(Pattern.quote("var_name_with_underscore"), Foo.class);
+
+		assertThat(path).isNotNull();
+		assertThat(path.getSegment()).isEqualTo("var_name_with_underscore");
+		assertThat(path.hasNext()).isFalse();
+	}
+
 	private class Foo {
 
 		String userName;
 		String _email;
 		String UUID;
+		String var_name_with_underscore;
 	}
 
 	private class Bar {

src/test/java/org/springframework/data/mapping/model/AbstractPersistentPropertyUnitTests.java

@@ -43,6 +43,7 @@ import org.springframework.util.ReflectionUtils;
  * Unit tests for {@link AbstractPersistentProperty}.
  * 
  * @author Oliver Gierke
+ * @author Christoph Strobl
  */
 public class AbstractPersistentPropertyUnitTests {
 
@@ -192,6 +193,13 @@ public class AbstractPersistentPropertyUnitTests {
 		assertThat(property.isEntity()).isFalse();
 	}
 
+	@Test // DATACMNS-867
+	public void resolvesFieldNameWithUnderscoresCorrectly() {
+
+		SamplePersistentProperty property = getProperty(TestClassComplex.class, "var_name_with_underscores");
+		assertThat(property.getName()).isEqualTo("var_name_with_underscores");
+	}
+
 	private <T> BasicPersistentEntity<T, SamplePersistentProperty> getEntity(Class<T> type) {
 		return new BasicPersistentEntity<>(ClassTypeInformation.from(type));
 	}
@@ -244,6 +252,7 @@ public class AbstractPersistentPropertyUnitTests {
 		Map map;
 		Collection collection;
 		transient Object transientField;
+		String var_name_with_underscores;
 	}
 
 	class AccessorTestClass {