Fix regression in client codecs

Restore the correct client-side default for whether StringDecoder
should split on new lines. It is true forthe server and false for the
client by default.

The regression was introduced in the recent refactoring:
f8a21ab11b (diff-0175d58138b2e8b2bec087ffe0495340)

spring-web/src/main/java/org/springframework/http/codec/AbstractCodecConfigurer.java

@@ -181,7 +181,7 @@ public abstract class AbstractCodecConfigurer {
 	/**
 	 * A registry and a factory for built-in HTTP message readers and writers.
 	 */
-	public static class DefaultCodecConfigurer {
+	public abstract static class DefaultCodecConfigurer {
 
 		private boolean suppressed = false;
 
@@ -280,13 +280,9 @@ public abstract class AbstractCodecConfigurer {
 		}
 
 
-		protected void addStringReaderTextOnlyTo(List<HttpMessageReader<?>> result) {
-			addReaderTo(result, () -> new DecoderHttpMessageReader<>(StringDecoder.textPlainOnly(true)));
-		}
+		protected abstract void addStringReaderTextOnlyTo(List<HttpMessageReader<?>> result);
 
-		protected void addStringReaderTo(List<HttpMessageReader<?>> result) {
-			addReaderTo(result, () -> new DecoderHttpMessageReader<>(StringDecoder.allMimeTypes(true)));
-		}
+		protected abstract void addStringReaderTo(List<HttpMessageReader<?>> result);
 
 		protected void addStringWriterTextPlainOnlyTo(List<HttpMessageWriter<?>> result) {
 			addWriterTo(result, () -> new EncoderHttpMessageWriter<>(CharSequenceEncoder.textPlainOnly()));

spring-web/src/main/java/org/springframework/http/codec/ClientCodecConfigurer.java

@@ -18,6 +18,7 @@ package org.springframework.http.codec;
 import java.util.List;
 
 import org.springframework.core.codec.Decoder;
+import org.springframework.core.codec.StringDecoder;
 import org.springframework.http.codec.json.Jackson2JsonDecoder;
 
 /**
@@ -79,6 +80,14 @@ public class ClientCodecConfigurer extends AbstractCodecConfigurer {
 
 		// Internal methods for building a list of default readers or writers...
 
+		protected void addStringReaderTextOnlyTo(List<HttpMessageReader<?>> result) {
+			addReaderTo(result, () -> new DecoderHttpMessageReader<>(StringDecoder.textPlainOnly(false)));
+		}
+
+		protected void addStringReaderTo(List<HttpMessageReader<?>> result) {
+			addReaderTo(result, () -> new DecoderHttpMessageReader<>(StringDecoder.allMimeTypes(false)));
+		}
+
 		private void addServerSentEventReaderTo(List<HttpMessageReader<?>> result) {
 			addReaderTo(result, () -> findReader(ServerSentEventHttpMessageReader.class, () -> {
 				Decoder<?> decoder = null;

spring-web/src/main/java/org/springframework/http/codec/ServerCodecConfigurer.java

@@ -18,6 +18,7 @@ package org.springframework.http.codec;
 import java.util.List;
 
 import org.springframework.core.codec.Encoder;
+import org.springframework.core.codec.StringDecoder;
 import org.springframework.http.codec.json.Jackson2JsonEncoder;
 
 /**
@@ -78,6 +79,14 @@ public class ServerCodecConfigurer extends AbstractCodecConfigurer {
 
 		// Internal methods for building a list of default readers or writers...
 
+		protected void addStringReaderTextOnlyTo(List<HttpMessageReader<?>> result) {
+			addReaderTo(result, () -> new DecoderHttpMessageReader<>(StringDecoder.textPlainOnly(true)));
+		}
+
+		protected void addStringReaderTo(List<HttpMessageReader<?>> result) {
+			addReaderTo(result, () -> new DecoderHttpMessageReader<>(StringDecoder.allMimeTypes(true)));
+		}
+
 		private void addServerSentEventWriterTo(List<HttpMessageWriter<?>> result) {
 			addWriterTo(result, () -> findWriter(ServerSentEventHttpMessageWriter.class, () -> {
 				Encoder<?> encoder = null;

spring-web/src/test/java/org/springframework/http/codec/ClientCodecConfigurerTests.java

@@ -15,11 +15,16 @@
  */
 package org.springframework.http.codec;
 
+import java.nio.charset.StandardCharsets;
+import java.time.Duration;
+import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import org.junit.Test;
+import reactor.core.publisher.Flux;
 
+import org.springframework.core.ResolvableType;
 import org.springframework.core.codec.ByteArrayDecoder;
 import org.springframework.core.codec.ByteArrayEncoder;
 import org.springframework.core.codec.ByteBufferDecoder;
@@ -31,6 +36,7 @@ import org.springframework.core.codec.Decoder;
 import org.springframework.core.codec.Encoder;
 import org.springframework.core.codec.ResourceDecoder;
 import org.springframework.core.codec.StringDecoder;
+import org.springframework.core.io.buffer.DefaultDataBufferFactory;
 import org.springframework.http.MediaType;
 import org.springframework.http.codec.json.Jackson2JsonDecoder;
 import org.springframework.http.codec.json.Jackson2JsonEncoder;
@@ -112,10 +118,17 @@ public class ClientCodecConfigurerTests {
 		return ((EncoderHttpMessageWriter) writer).getEncoder();
 	}
 
+	@SuppressWarnings("unchecked")
 	private void assertStringDecoder(Decoder<?> decoder, boolean textOnly) {
 		assertEquals(StringDecoder.class, decoder.getClass());
 		assertTrue(decoder.canDecode(forClass(String.class), MimeTypeUtils.TEXT_PLAIN));
 		assertEquals(!textOnly, decoder.canDecode(forClass(String.class), MediaType.TEXT_EVENT_STREAM));
+
+		Flux<String> decoded = (Flux<String>) decoder.decode(
+				Flux.just(new DefaultDataBufferFactory().wrap("line1\nline2".getBytes(StandardCharsets.UTF_8))),
+				ResolvableType.forClass(String.class), MimeTypeUtils.TEXT_PLAIN, Collections.emptyMap());
+
+		assertEquals(Collections.singletonList("line1\nline2"), decoded.collectList().block(Duration.ZERO));
 	}
 
 	private void assertStringEncoder(Encoder<?> encoder, boolean textOnly) {

spring-web/src/test/java/org/springframework/http/codec/CodecConfigurerTests.java

@@ -282,7 +282,19 @@ public class CodecConfigurerTests {
 	private static class TestCodecConfigurer extends AbstractCodecConfigurer {
 
 		private TestCodecConfigurer() {
-			super(new DefaultCodecConfigurer());
+			super(new TestDefaultCodecConfigurer());
+		}
+
+
+		private static class TestDefaultCodecConfigurer extends DefaultCodecConfigurer {
+
+			protected void addStringReaderTextOnlyTo(List<HttpMessageReader<?>> result) {
+				addReaderTo(result, () -> new DecoderHttpMessageReader<>(StringDecoder.textPlainOnly(true)));
+			}
+
+			protected void addStringReaderTo(List<HttpMessageReader<?>> result) {
+				addReaderTo(result, () -> new DecoderHttpMessageReader<>(StringDecoder.allMimeTypes(true)));
+			}
 		}
 	}
 

spring-web/src/test/java/org/springframework/http/codec/ServerCodecConfigurerTests.java

@@ -15,11 +15,17 @@
  */
 package org.springframework.http.codec;
 
+import java.nio.charset.StandardCharsets;
+import java.time.Duration;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import org.junit.Test;
+import reactor.core.publisher.Flux;
 
+import org.springframework.core.ResolvableType;
 import org.springframework.core.codec.ByteArrayDecoder;
 import org.springframework.core.codec.ByteArrayEncoder;
 import org.springframework.core.codec.ByteBufferDecoder;
@@ -31,6 +37,7 @@ import org.springframework.core.codec.Decoder;
 import org.springframework.core.codec.Encoder;
 import org.springframework.core.codec.ResourceDecoder;
 import org.springframework.core.codec.StringDecoder;
+import org.springframework.core.io.buffer.DefaultDataBufferFactory;
 import org.springframework.http.MediaType;
 import org.springframework.http.codec.json.Jackson2JsonDecoder;
 import org.springframework.http.codec.json.Jackson2JsonEncoder;
@@ -112,10 +119,17 @@ public class ServerCodecConfigurerTests {
 		return ((EncoderHttpMessageWriter) writer).getEncoder();
 	}
 
+	@SuppressWarnings("unchecked")
 	private void assertStringDecoder(Decoder<?> decoder, boolean textOnly) {
 		assertEquals(StringDecoder.class, decoder.getClass());
 		assertTrue(decoder.canDecode(forClass(String.class), MimeTypeUtils.TEXT_PLAIN));
 		assertEquals(!textOnly, decoder.canDecode(forClass(String.class), MediaType.TEXT_EVENT_STREAM));
+
+		Flux<String> flux = (Flux<String>) decoder.decode(
+				Flux.just(new DefaultDataBufferFactory().wrap("line1\nline2".getBytes(StandardCharsets.UTF_8))),
+				ResolvableType.forClass(String.class), MimeTypeUtils.TEXT_PLAIN, Collections.emptyMap());
+
+		assertEquals(Arrays.asList("line1\n", "line2"), flux.collectList().block(Duration.ZERO));
 	}
 
 	private void assertStringEncoder(Encoder<?> encoder, boolean textOnly) {