Include information about a property’s origin in binding failures

This commit enhances RelaxedDataBinder to include information about the
origin of a property (its original name before any prefix was removed
and its source) when it encounters an unwritable property. For example,
launching an application with a SERVER_HOME environment variable
configured will produce the following failure message:

Failed to bind 'SERVER_HOME' from 'systemEnvironment' to 'HOME' property
on 'org.springframework.boot.autoconfigure.web.ServerProperties'

Closes gh-3778

spring-boot/src/main/java/org/springframework/boot/bind/OriginCapablePropertyValue.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2012-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.bind;
+
+import org.springframework.beans.PropertyValue;
+import org.springframework.core.env.PropertySource;
+
+/**
+ * A {@link PropertyValue} that can provide information about its origin.
+ *
+ * @author Andy Wilkinson
+ */
+class OriginCapablePropertyValue extends PropertyValue {
+
+	private static final String ATTRIBUTE_PROPERTY_ORIGIN = "propertyOrigin";
+
+	private final PropertyOrigin origin;
+
+	public OriginCapablePropertyValue(PropertyValue propertyValue) {
+		this(propertyValue.getName(), propertyValue.getValue(),
+				(PropertyOrigin) propertyValue.getAttribute(ATTRIBUTE_PROPERTY_ORIGIN));
+	}
+
+	public OriginCapablePropertyValue(String name, Object value, String originName,
+			PropertySource<?> originSource) {
+		this(name, value, new PropertyOrigin(originSource, originName));
+	}
+
+	public OriginCapablePropertyValue(String name, Object value, PropertyOrigin origin) {
+		super(name, value);
+		this.origin = origin;
+		setAttribute(ATTRIBUTE_PROPERTY_ORIGIN, origin);
+	}
+
+	public PropertyOrigin getOrigin() {
+		return this.origin;
+	}
+
+	@Override
+	public String toString() {
+		String name = this.origin != null ? this.origin.getName() : this.getName();
+		String source = this.origin.getSource() != null ? this.origin.getSource()
+				.getName() : "unknown";
+		return "'" + name + "' from '" + source + "'";
+	}
+}

spring-boot/src/main/java/org/springframework/boot/bind/PropertyOrigin.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2012-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.bind;
+
+import org.springframework.core.env.PropertySource;
+
+/**
+ * The origin of a property, specifically its source and its name before any prefix was
+ * removed.
+ *
+ * @author Andy Wilkinson
+ * @since 1.3.0
+ */
+public class PropertyOrigin {
+
+	private final PropertySource<?> source;
+
+	private final String name;
+
+	PropertyOrigin(PropertySource<?> source, String name) {
+		this.name = name;
+		this.source = source;
+	}
+
+	public PropertySource<?> getSource() {
+		return this.source;
+	}
+
+	public String getName() {
+		return this.name;
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/bind/PropertySourcesPropertyValues.java

@@ -120,7 +120,7 @@ public class PropertySourcesPropertyValues implements PropertyValues {
 			for (String propertyName : source.getPropertyNames()) {
 				if (includes.matches(propertyName)) {
 					Object value = getEnumerableProperty(source, resolver, propertyName);
-					putIfAbsent(propertyName, value);
+					putIfAbsent(propertyName, value, source);
 				}
 			}
 		}
@@ -155,13 +155,14 @@ public class PropertySourcesPropertyValues implements PropertyValues {
 			if (value == null) {
 				value = source.getProperty(propertyName.toUpperCase());
 			}
-			putIfAbsent(propertyName, value);
+			putIfAbsent(propertyName, value, source);
 		}
 	}
 
-	private void putIfAbsent(String propertyName, Object value) {
+	private void putIfAbsent(String propertyName, Object value, PropertySource<?> source) {
 		if (value != null && !this.propertyValues.containsKey(propertyName)) {
-			this.propertyValues.put(propertyName, new PropertyValue(propertyName, value));
+			this.propertyValues.put(propertyName, new OriginCapablePropertyValue(
+					propertyName, value, propertyName, source));
 		}
 	}
 
@@ -180,7 +181,8 @@ public class PropertySourcesPropertyValues implements PropertyValues {
 		for (PropertySource<?> source : this.propertySources) {
 			Object value = source.getProperty(propertyName);
 			if (value != null) {
-				propertyValue = new PropertyValue(propertyName, value);
+				propertyValue = new OriginCapablePropertyValue(propertyName, value,
+						propertyName, source);
 				this.propertyValues.put(propertyName, propertyValue);
 				return propertyValue;
 			}

spring-boot/src/main/java/org/springframework/boot/bind/RelaxedBindingNotWritablePropertyException.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2012-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.bind;
+
+import org.springframework.beans.NotWritablePropertyException;
+
+/**
+ * A custom {@link NotWritablePropertyException} that is thrown when a failure occurs
+ * during relaxed binding
+ *
+ * @see RelaxedDataBinder
+ * @author Andy Wilkinson
+ * @since 1.3.0
+ */
+public class RelaxedBindingNotWritablePropertyException extends
+		NotWritablePropertyException {
+
+	private final String message;
+
+	private final PropertyOrigin propertyOrigin;
+
+	RelaxedBindingNotWritablePropertyException(NotWritablePropertyException ex,
+			PropertyOrigin propertyOrigin) {
+		super(ex.getBeanClass(), ex.getPropertyName());
+		this.propertyOrigin = propertyOrigin;
+		this.message = "Failed to bind '" + propertyOrigin.getName() + "' from '"
+				+ propertyOrigin.getSource().getName() + "' to '" + ex.getPropertyName()
+				+ "' property on '" + ex.getBeanClass().getName() + "'";
+	}
+
+	@Override
+	public String getMessage() {
+		return this.message;
+	}
+
+	public PropertyOrigin getPropertyOrigin() {
+		return this.propertyOrigin;
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/bind/RelaxedDataBinder.java

@@ -29,13 +29,17 @@ import java.util.Set;
 
 import org.springframework.beans.BeanWrapper;
 import org.springframework.beans.BeanWrapperImpl;
+import org.springframework.beans.BeansException;
 import org.springframework.beans.InvalidPropertyException;
 import org.springframework.beans.MutablePropertyValues;
+import org.springframework.beans.NotWritablePropertyException;
 import org.springframework.beans.PropertyValue;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.StringUtils;
+import org.springframework.validation.AbstractPropertyBindingResult;
+import org.springframework.validation.BeanPropertyBindingResult;
 import org.springframework.validation.DataBinder;
 
 /**
@@ -115,19 +119,8 @@ public class RelaxedDataBinder extends DataBinder {
 		return this;
 	}
 
-	@Override
-	public void initBeanPropertyAccess() {
-		super.initBeanPropertyAccess();
-		// Hook in the RelaxedConversionService
-		getInternalBindingResult().initConversion(
-				new RelaxedConversionService(getConversionService()));
-	}
-
 	@Override
 	protected void doBind(MutablePropertyValues propertyValues) {
-		// Harmless additional property editor comes in very handy sometimes...
-		getPropertyEditorRegistry().registerCustomEditor(InetAddress.class,
-				new InetAddressEditor());
 		super.doBind(modifyProperties(propertyValues, getTarget()));
 	}
 
@@ -213,7 +206,9 @@ public class RelaxedDataBinder extends DataBinder {
 				if (name.startsWith(candidate)) {
 					name = name.substring(candidate.length());
 					if (!(this.ignoreNestedProperties && name.contains("."))) {
-						rtn.add(name, value.getValue());
+						PropertyOrigin propertyOrigin = findPropertyOrigin(value);
+						rtn.addPropertyValue(new OriginCapablePropertyValue(name, value
+								.getValue(), propertyOrigin));
 					}
 				}
 			}
@@ -245,6 +240,44 @@ public class RelaxedDataBinder extends DataBinder {
 		return initializePath(wrapper, new BeanPath(path), 0);
 	}
 
+	@Override
+	protected AbstractPropertyBindingResult createBeanPropertyBindingResult() {
+		return new BeanPropertyBindingResult(getTarget(), getObjectName(),
+				isAutoGrowNestedPaths(), getAutoGrowCollectionLimit()) {
+			@Override
+			protected BeanWrapper createBeanWrapper() {
+				BeanWrapper beanWrapper = new BeanWrapperImpl(getTarget()) {
+					@Override
+					public void setPropertyValue(PropertyValue pv) throws BeansException {
+						try {
+							super.setPropertyValue(pv);
+						}
+						catch (NotWritablePropertyException ex) {
+							PropertyOrigin origin = findPropertyOrigin(pv);
+							if (origin != null) {
+								throw new RelaxedBindingNotWritablePropertyException(ex,
+										origin);
+							}
+							throw ex;
+						}
+					}
+				};
+				beanWrapper.setConversionService(new RelaxedConversionService(
+						getConversionService()));
+				beanWrapper.registerCustomEditor(InetAddress.class,
+						new InetAddressEditor());
+				return beanWrapper;
+			}
+		};
+	}
+
+	private PropertyOrigin findPropertyOrigin(PropertyValue propertyValue) {
+		if (propertyValue instanceof OriginCapablePropertyValue) {
+			return ((OriginCapablePropertyValue) propertyValue).getOrigin();
+		}
+		return new OriginCapablePropertyValue(propertyValue).getOrigin();
+	}
+
 	private String initializePath(BeanWrapper wrapper, BeanPath path, int index) {
 		String prefix = path.prefix(index);
 		String key = path.name(index);

spring-boot/src/main/java/org/springframework/boot/context/properties/ConfigurationPropertiesBindingPostProcessor.java

@@ -309,7 +309,7 @@ public class ConfigurationPropertiesBindingPostProcessor implements BeanPostProc
 			return "";
 		}
 		StringBuilder details = new StringBuilder();
-		details.append("target=").append(
+		details.append("prefix=").append(
 				(StringUtils.hasLength(annotation.value()) ? annotation.value()
 						: annotation.prefix()));
 		details.append(", ignoreInvalidFields=").append(annotation.ignoreInvalidFields());

spring-boot/src/test/java/org/springframework/boot/context/properties/ConfigurationPropertiesBindingPostProcessorTests.java

@@ -30,6 +30,7 @@ import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.beans.factory.support.AbstractBeanDefinition;
 import org.springframework.beans.factory.support.GenericBeanDefinition;
+import org.springframework.boot.bind.RelaxedBindingNotWritablePropertyException;
 import org.springframework.boot.test.EnvironmentTestUtils;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
@@ -42,6 +43,7 @@ import org.springframework.validation.ValidationUtils;
 import org.springframework.validation.Validator;
 
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.startsWith;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
@@ -85,6 +87,23 @@ public class ConfigurationPropertiesBindingPostProcessorTests {
 		}
 	}
 
+	@Test
+	public void unknonwFieldFailureMessageContainsDetailsOfPropertyOrigin() {
+		this.context = new AnnotationConfigApplicationContext();
+		EnvironmentTestUtils.addEnvironment(this.context, "com.example.baz:spam");
+		this.context.register(TestConfiguration.class);
+		try {
+			this.context.refresh();
+			fail("Expected exception");
+		}
+		catch (BeanCreationException ex) {
+			RelaxedBindingNotWritablePropertyException bex = (RelaxedBindingNotWritablePropertyException) ex.getRootCause();
+			assertThat(bex.getMessage(),
+					startsWith("Failed to bind 'com.example.baz' from 'test' to 'baz' "
+							+ "property on '" + TestConfiguration.class.getName()));
+		}
+	}
+
 	@Test
 	public void testValidationWithoutJSR303() {
 		this.context = new AnnotationConfigApplicationContext();
@@ -402,6 +421,23 @@ public class ConfigurationPropertiesBindingPostProcessorTests {
 
 	}
 
+	@Configuration
+	@EnableConfigurationProperties
+	@ConfigurationProperties(prefix = "com.example", ignoreUnknownFields = false)
+	public static class TestConfiguration {
+
+		private String bar;
+
+		public void setBar(String bar) {
+			this.bar = bar;
+		}
+
+		public String getBar() {
+			return this.bar;
+		}
+
+	}
+
 	@ConfigurationProperties(prefix = "test")
 	public static class PropertyWithJSR303 extends PropertyWithoutJSR303 {