Ignore top-level ConfigurationProperty binding failures

Fixes gh-12357

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

@@ -26,6 +26,7 @@ import org.springframework.boot.context.properties.bind.Bindable;
 import org.springframework.boot.context.properties.bind.Binder;
 import org.springframework.boot.context.properties.bind.PropertySourcesPlaceholdersResolver;
 import org.springframework.boot.context.properties.bind.handler.IgnoreErrorsBindHandler;
+import org.springframework.boot.context.properties.bind.handler.IgnoreTopLevelConverterNotFoundBindHandler;
 import org.springframework.boot.context.properties.bind.handler.NoUnboundElementsBindHandler;
 import org.springframework.boot.context.properties.bind.validation.ValidationBindHandler;
 import org.springframework.boot.context.properties.source.ConfigurationPropertySource;
@@ -103,7 +104,7 @@ class ConfigurationPropertiesBinder {
 
 	private BindHandler getBindHandler(ConfigurationProperties annotation,
 			List<Validator> validators) {
-		BindHandler handler = BindHandler.DEFAULT;
+		BindHandler handler = new IgnoreTopLevelConverterNotFoundBindHandler();
 		if (annotation.ignoreInvalidFields()) {
 			handler = new IgnoreErrorsBindHandler(handler);
 		}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/handler/IgnoreTopLevelConverterNotFoundBindHandler.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-2017 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.context.properties.bind.handler;
+
+import org.springframework.boot.context.properties.bind.AbstractBindHandler;
+import org.springframework.boot.context.properties.bind.BindContext;
+import org.springframework.boot.context.properties.bind.BindHandler;
+import org.springframework.boot.context.properties.bind.Bindable;
+import org.springframework.boot.context.properties.source.ConfigurationPropertyName;
+import org.springframework.core.convert.ConverterNotFoundException;
+
+/**
+ * {@link BindHandler} that can be used to ignore top-level {@link ConverterNotFoundException}s.
+ *
+ * @author Madhura Bhave
+ * @since 2.0.0
+ */
+public class IgnoreTopLevelConverterNotFoundBindHandler extends AbstractBindHandler {
+
+	@Override
+	public Object onFailure(ConfigurationPropertyName name, Bindable<?> target,
+			BindContext context, Exception error) throws Exception {
+		if (context.getDepth() == 0 && error instanceof ConverterNotFoundException) {
+			return null;
+		}
+		throw error;
+	}
+
+}
+
+

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

@@ -745,6 +745,11 @@ public class ConfigurationPropertiesTests {
 		assertThat(bean.getFile()).isEqualTo(new File("."));
 	}
 
+	@Test
+	public void loadWhenTopLevelConverterNotFoundExceptionShouldNotFail() {
+		load(PersonProperties.class, "test=boot");
+	}
+
 	private AnnotationConfigApplicationContext load(Class<?> configuration,
 			String... inlinedProperties) {
 		return load(new Class<?>[] { configuration }, inlinedProperties);

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/bind/handler/IgnoreTopLevelConverterNotFoundBindHandlerTests.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright 2012-2017 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.context.properties.bind.handler;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import org.springframework.boot.context.properties.bind.BindException;
+import org.springframework.boot.context.properties.bind.Bindable;
+import org.springframework.boot.context.properties.bind.Binder;
+import org.springframework.boot.context.properties.source.ConfigurationPropertySource;
+import org.springframework.boot.context.properties.source.MockConfigurationPropertySource;
+import org.springframework.core.convert.ConverterNotFoundException;
+
+import static org.hamcrest.Matchers.instanceOf;
+
+/**
+ * Tests for {@link IgnoreTopLevelConverterNotFoundBindHandler}.
+ *
+ * @author Madhura Bhave
+ */
+public class IgnoreTopLevelConverterNotFoundBindHandlerTests {
+
+	@Rule
+	public ExpectedException thrown = ExpectedException.none();
+
+	private List<ConfigurationPropertySource> sources = new ArrayList<>();
+
+	private Binder binder;
+
+	@Before
+	public void setup() {
+		MockConfigurationPropertySource source = new MockConfigurationPropertySource();
+		source.put("example", "bar");
+		this.sources.add(source);
+		this.binder = new Binder(this.sources);
+	}
+
+	@After
+	public void tearDown() {
+		this.sources.clear();
+	}
+
+	@Test
+	public void bindWhenHandlerNotPresentShouldFail() {
+		this.thrown.expectCause(instanceOf(ConverterNotFoundException.class));
+		this.binder.bind("example", Bindable.of(Example.class));
+	}
+
+	@Test
+	public void bindWhenTopLevelContextAndExceptionIgnorableShouldNotFail() {
+		this.binder.bind("example", Bindable.of(Example.class), new IgnoreTopLevelConverterNotFoundBindHandler());
+	}
+
+	@Test
+	public void bindWhenExceptionNotIgnorableShouldNotFail() {
+		MockConfigurationPropertySource source = new MockConfigurationPropertySource();
+		source.put("example.foo", "1");
+		this.sources.add(source);
+		this.thrown.expectCause(instanceOf(IllegalStateException.class));
+		this.binder.bind("example", Bindable.of(Example.class), new IgnoreTopLevelConverterNotFoundBindHandler());
+	}
+
+	@Test
+	public void bindWhenExceptionInNestedContextShouldFail() {
+		MockConfigurationPropertySource source = new MockConfigurationPropertySource();
+		source.put("example.map", "hello");
+		this.sources.add(source);
+		this.thrown.expect(BindException.class);
+		this.thrown.expectCause(instanceOf(ConverterNotFoundException.class));
+		this.binder.bind("example", Bindable.of(Example.class), new IgnoreTopLevelConverterNotFoundBindHandler());
+	}
+
+	public static class Example {
+
+		private int foo;
+
+		private Map<String, String> map;
+
+		public int getFoo() {
+			return this.foo;
+		}
+
+		public void setFoo(int foo) {
+			throw new IllegalStateException();
+		}
+
+		public Map<String, String> getMap() {
+			return this.map;
+		}
+
+		public void setMap(Map<String, String> map) {
+			this.map = map;
+		}
+
+	}
+
+}