JsonEOFException is wrapped as DecodingError

Jackson2Tokenizer now also wraps JsonProcessingException's on
endOfInput(), as it also does in tokenize(DataBuffer). This ensures
treating those errors as 400 vs 500.

Issue: SPR-16521

spring-web/src/main/java/org/springframework/http/codec/json/Jackson2Tokenizer.java

@@ -27,7 +27,6 @@ import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.core.JsonToken;
 import com.fasterxml.jackson.core.async.ByteArrayFeeder;
 import com.fasterxml.jackson.databind.util.TokenBuffer;
-import org.jetbrains.annotations.NotNull;
 import reactor.core.publisher.Flux;
 
 import org.springframework.core.codec.DecodingException;
@@ -114,12 +113,15 @@ class Jackson2Tokenizer {
 		try {
 			return parseTokenBufferFlux();
 		}
+		catch (JsonProcessingException ex) {
+			return Flux.error(new DecodingException(
+					"JSON decoding error: " + ex.getOriginalMessage(), ex));
+		}
 		catch (IOException ex) {
 			return Flux.error(ex);
 		}
 	}
 
-	@NotNull
 	private Flux<TokenBuffer> parseTokenBufferFlux() throws IOException {
 		List<TokenBuffer> result = new ArrayList<>();
 

spring-web/src/test/java/org/springframework/http/codec/json/Jackson2TokenizerTests.java

@@ -32,11 +32,12 @@ import org.skyscreamer.jsonassert.JSONAssert;
 import reactor.core.publisher.Flux;
 import reactor.test.StepVerifier;
 
+import org.springframework.core.codec.DecodingException;
 import org.springframework.core.io.buffer.AbstractDataBufferAllocatingTestCase;
 import org.springframework.core.io.buffer.DataBuffer;
 
-import static java.util.Arrays.asList;
-import static java.util.Collections.singletonList;
+import static java.util.Arrays.*;
+import static java.util.Collections.*;
 
 /**
  * @author Arjen Poutsma
@@ -174,6 +175,14 @@ public class Jackson2TokenizerTests extends AbstractDataBufferAllocatingTestCase
 				asList("1", "2", "3"), true);
 	}
 
+	@Test(expected = DecodingException.class) // SPR-16521
+	public void jsonEOFExceptionIsWrappedAsDecodingError() {
+		Flux<DataBuffer> source = Flux.just(stringBuffer("{\"status\": \"noClosingQuote}"));
+		Flux<TokenBuffer> tokens = Jackson2Tokenizer.tokenize(source, this.jsonFactory, false);
+		tokens.blockLast();
+	}
+
+
 	private void testTokenize(List<String> source, List<String> expected, boolean tokenizeArrayElements) {
 		Flux<DataBuffer> sourceFlux = Flux.fromIterable(source)
 				.map(this::stringBuffer);