Exclude Part and MultipartFile from nested constructor binding

Closes gh-31669

spring-web/src/main/java/org/springframework/web/bind/ServletRequestDataBinder.java

@@ -24,6 +24,7 @@ import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.Part;
 
 import org.springframework.beans.MutablePropertyValues;
+import org.springframework.core.MethodParameter;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
 import org.springframework.lang.Nullable;
@@ -120,6 +121,13 @@ public class ServletRequestDataBinder extends WebDataBinder {
 		return new ServletRequestValueResolver(request, this);
 	}
 
+	@Override
+	protected boolean shouldConstructArgument(MethodParameter param) {
+		Class<?> type = param.nestedIfOptional().getNestedParameterType();
+		return (super.shouldConstructArgument(param) &&
+				!MultipartFile.class.isAssignableFrom(type) && !Part.class.isAssignableFrom(type));
+	}
+
 	/**
 	 * Bind the parameters of the given request to this binder's target,
 	 * also binding multipart files in case of a multipart request.

spring-web/src/main/java/org/springframework/web/bind/support/WebRequestDataBinder.java

@@ -18,8 +18,10 @@ package org.springframework.web.bind.support;
 
 import jakarta.servlet.ServletRequest;
 import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.Part;
 
 import org.springframework.beans.MutablePropertyValues;
+import org.springframework.core.MethodParameter;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
@@ -30,6 +32,7 @@ import org.springframework.web.bind.ServletRequestDataBinder;
 import org.springframework.web.bind.WebDataBinder;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.context.request.WebRequest;
+import org.springframework.web.multipart.MultipartFile;
 import org.springframework.web.multipart.MultipartRequest;
 import org.springframework.web.multipart.support.StandardServletPartUtils;
 
@@ -118,6 +121,12 @@ public class WebRequestDataBinder extends WebDataBinder {
 		}
 	}
 
+	@Override
+	protected boolean shouldConstructArgument(MethodParameter param) {
+		Class<?> type = param.nestedIfOptional().getNestedParameterType();
+		return (super.shouldConstructArgument(param) &&
+				!MultipartFile.class.isAssignableFrom(type) && !Part.class.isAssignableFrom(type));
+	}
 
 	/**
 	 * Bind the parameters of the given request to this binder's target,