Copy strategiesConfigurers when cloning WebClient.Builder

This commit fixes the missing `strategiesConfigurers` copy when the
`WebClient.Builder` is cloned.

Fixes gh-24329

spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -114,6 +114,7 @@ public DefaultWebClientBuilder(DefaultWebClientBuilder other) {
 		this.filters = other.filters != null ? new ArrayList<>(other.filters) : null;
 		this.connector = other.connector;
 		this.strategies = other.strategies;
+		this.strategiesConfigurers = other.strategiesConfigurers != null ? new ArrayList<>(other.strategiesConfigurers) : null;
 		this.exchangeFunction = other.exchangeFunction;
 	}
 

spring-webflux/src/test/java/org/springframework/web/reactive/function/client/DefaultWebClientTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -20,6 +20,7 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.function.Consumer;
 import java.util.function.Predicate;
 
 import org.junit.jupiter.api.BeforeEach;
@@ -36,6 +37,7 @@
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.codec.ClientCodecConfigurer;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
@@ -231,6 +233,23 @@ public void mutateDoesCopy() {
 		builder1a.defaultCookies(cookies -> assertThat(cookies.size()).isEqualTo(2));
 	}
 
+	@Test
+	void cloneBuilder() {
+		Consumer<ClientCodecConfigurer> codecsConfig = c -> {};
+		ExchangeFunction exchangeFunction = request -> Mono.empty();
+		WebClient.Builder builder = WebClient.builder().baseUrl("https://example.org")
+				.exchangeFunction(exchangeFunction)
+				.filter((request, next) -> Mono.empty())
+				.codecs(codecsConfig);
+
+		WebClient.Builder clonedBuilder = builder.clone();
+
+		assertThat(clonedBuilder).extracting("baseUrl").isEqualTo("https://example.org");
+		assertThat(clonedBuilder).extracting("filters").isNotNull();
+		assertThat(clonedBuilder).extracting("strategiesConfigurers").isNotNull();
+		assertThat(clonedBuilder).extracting("exchangeFunction").isEqualTo(exchangeFunction);
+	}
+
 	@Test
 	public void withStringAttribute() {
 		Map<String, Object> actual = new HashMap<>();