Fix package tangle in binder

Update the `BinderConversionService` so that it no longer references
classes from `org.springframework.boot.context.properties.bind`.

See gh-10592

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

@@ -227,10 +227,8 @@ public class Binder {
 	}
 
 	private <T> T convert(Object value, Bindable<T> target) {
-		if (value == null) {
-			return null;
-		}
-		return this.conversionService.convert(value, target);
+		return ResolvableTypeDescriptor.forBindable(target)
+				.convert(this.conversionService, value);
 	}
 
 	private <T> Object bindObject(ConfigurationPropertyName name, Bindable<T> target,
@@ -287,7 +285,7 @@ public class Binder {
 		context.setConfigurationProperty(property);
 		Object result = property.getValue();
 		result = this.placeholdersResolver.resolvePlaceholders(result);
-		result = this.conversionService.convert(result, target);
+		result = convert(result, target);
 		return result;
 	}
 

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

@@ -122,11 +122,10 @@ abstract class IndexedElementsBinder<T> extends AggregateBinder<T> {
 		}
 	}
 
-	@SuppressWarnings("unchecked")
 	private <C> C convert(Object value, ResolvableType type) {
 		value = getContext().getPlaceholdersResolver().resolvePlaceholders(value);
 		BinderConversionService conversionService = getContext().getConversionService();
-		return (C) conversionService.convert(value, type);
+		return ResolvableTypeDescriptor.forType(type).convert(conversionService, value);
 	}
 
 	/**

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

@@ -20,7 +20,6 @@ import java.util.Collection;
 import java.util.Map;
 import java.util.Properties;
 
-import org.springframework.boot.context.properties.bind.convert.BinderConversionService;
 import org.springframework.boot.context.properties.source.ConfigurationProperty;
 import org.springframework.boot.context.properties.source.ConfigurationPropertyName;
 import org.springframework.boot.context.properties.source.ConfigurationPropertyName.Form;
@@ -102,8 +101,7 @@ class MapBinder extends AggregateBinder<Map<Object, Object>> {
 				for (ConfigurationPropertyName name : (IterableConfigurationPropertySource) source) {
 					Bindable<?> valueBindable = getValueBindable(name);
 					ConfigurationPropertyName entryName = getEntryName(source, name);
-					Object key = getContext().getConversionService()
-							.convert(getKeyName(entryName), this.keyType);
+					Object key = convert(getKeyName(entryName), this.keyType);
 					map.computeIfAbsent(key,
 							(k) -> this.elementBinder.bind(entryName, valueBindable));
 				}
@@ -159,9 +157,17 @@ class MapBinder extends AggregateBinder<Map<Object, Object>> {
 			}
 			Object value = property.getValue();
 			value = getContext().getPlaceholdersResolver().resolvePlaceholders(value);
-			BinderConversionService conversionService = getContext()
-					.getConversionService();
-			return conversionService.canConvert(value, this.valueType);
+			return canConvert(value, this.valueType);
+		}
+
+		private boolean canConvert(Object source, ResolvableType targetType) {
+			return ResolvableTypeDescriptor.forType(targetType)
+					.canConvert(getContext().getConversionService(), source);
+		}
+
+		private Object convert(Object source, ResolvableType targetType) {
+			return ResolvableTypeDescriptor.forType(targetType)
+					.convert(getContext().getConversionService(), source);
 		}
 
 		private String getKeyName(ConfigurationPropertyName name) {

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

@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.context.properties.bind.convert;
+package org.springframework.boot.context.properties.bind;
 
 import java.lang.annotation.Annotation;
 
-import org.springframework.boot.context.properties.bind.Bindable;
 import org.springframework.core.ResolvableType;
+import org.springframework.core.convert.ConversionException;
+import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.TypeDescriptor;
 
 /**
@@ -35,12 +36,40 @@ final class ResolvableTypeDescriptor extends TypeDescriptor {
 		super(resolvableType, null, annotations);
 	}
 
+	/**
+	 * Determine if the specified source object can be converted to this type.
+	 * @param conversionService the backing conversion service
+	 * @param source the source to check
+	 * @return {@code true} if conversion can be performed
+	 */
+	public boolean canConvert(ConversionService conversionService, Object source) {
+		TypeDescriptor sourceType = TypeDescriptor.forObject(source);
+		return conversionService.canConvert(sourceType, this);
+	}
+
+	/**
+	 * Convert the given source object into this type.
+	 * @param conversionService the source conversion service
+	 * @param value the value to convert
+	 * @param <T> the target type
+	 * @return the converted value
+	 * @throws ConversionException if a conversion exception occurred
+	 */
+	@SuppressWarnings("unchecked")
+	public <T> T convert(ConversionService conversionService, Object value) {
+		if (value == null) {
+			return null;
+		}
+		TypeDescriptor sourceType = TypeDescriptor.forObject(value);
+		return (T) conversionService.convert(value, sourceType, this);
+	}
+
 	/**
 	 * Create a {@link TypeDescriptor} for the specified {@link Bindable}.
 	 * @param bindable the bindable
 	 * @return the type descriptor
 	 */
-	public static TypeDescriptor forBindable(Bindable<?> bindable) {
+	public static ResolvableTypeDescriptor forBindable(Bindable<?> bindable) {
 		return forType(bindable.getType(), bindable.getAnnotations());
 	}
 
@@ -50,7 +79,8 @@ final class ResolvableTypeDescriptor extends TypeDescriptor {
 	 * @param annotations the annotations to include
 	 * @return the type descriptor
 	 */
-	public static TypeDescriptor forType(ResolvableType type, Annotation... annotations) {
+	public static ResolvableTypeDescriptor forType(ResolvableType type,
+			Annotation... annotations) {
 		return new ResolvableTypeDescriptor(type, annotations);
 	}
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/convert/BinderConversionService.java

@@ -18,9 +18,7 @@ package org.springframework.boot.context.properties.bind.convert;
 
 import java.util.function.Function;
 
-import org.springframework.boot.context.properties.bind.Bindable;
 import org.springframework.boot.context.properties.bind.Binder;
-import org.springframework.core.ResolvableType;
 import org.springframework.core.convert.ConversionException;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.ConverterNotFoundException;
@@ -54,19 +52,6 @@ public class BinderConversionService implements ConversionService {
 		this.additionalConversionService = createAdditionalConversionService();
 	}
 
-	/**
-	 * Return {@code true} if the given source object can be converted to the
-	 * {@code targetType}.
-	 * @param source the source object
-	 * @param targetType the target type to convert to (required)
-	 * @return {@code true} if a conversion can be performed, {@code false} if not
-	 * @throws IllegalArgumentException if {@code targetType} is {@code null}
-	 */
-	public boolean canConvert(Object source, ResolvableType targetType) {
-		TypeDescriptor sourceType = TypeDescriptor.forObject(source);
-		return canConvert(sourceType, ResolvableTypeDescriptor.forType(targetType));
-	}
-
 	@Override
 	public boolean canConvert(Class<?> sourceType, Class<?> targetType) {
 		return (this.conversionService != null
@@ -81,20 +66,6 @@ public class BinderConversionService implements ConversionService {
 				|| this.additionalConversionService.canConvert(sourceType, targetType);
 	}
 
-	@SuppressWarnings("unchecked")
-	public <T> T convert(Object value, ResolvableType type) {
-		TypeDescriptor sourceType = TypeDescriptor.forObject(value);
-		TypeDescriptor targetType = ResolvableTypeDescriptor.forType(type);
-		return (T) convert(value, sourceType, targetType);
-	}
-
-	@SuppressWarnings("unchecked")
-	public <T> T convert(Object value, Bindable<T> bindable) {
-		TypeDescriptor sourceType = TypeDescriptor.forObject(value);
-		TypeDescriptor targetType = ResolvableTypeDescriptor.forBindable(bindable);
-		return (T) convert(value, sourceType, targetType);
-	}
-
 	@Override
 	public <T> T convert(Object source, Class<T> targetType) {
 		return callConversionService((c) -> c.convert(source, targetType));

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

@@ -14,14 +14,13 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.context.properties.bind.convert;
+package org.springframework.boot.context.properties.bind;
 
 import java.lang.annotation.Annotation;
 import java.util.List;
 
 import org.junit.Test;
 
-import org.springframework.boot.context.properties.bind.Bindable;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.core.convert.TypeDescriptor;