Minor tweaking

release-notes/CREDITS-2.x

@@ -456,3 +456,8 @@ Jared Stehler (@jaredstehler)
 Zhanghao (@zhangOranges)
  * Contributed #1305: Make helper methods of `WriterBasedJsonGenerator` non-final to allow overriding
   (2.18.0)
+
+Justin Gosselin (@jgosselin-accesso)
+ * Reported #1359: Non-surrogate characters being incorrectly combined when
+  `JsonWriteFeature.COMBINE_UNICODE_SURROGATES_IN_UTF8` is enabled
+  (2.18.2)

release-notes/VERSION-2.x

@@ -18,6 +18,10 @@ a pure JSON library.
 
 #1353: Use fastdoubleparser 1.0.90
  (fixed by @pjfanning)
+#1359: Non-surrogate characters being incorrectly combined when
+  `JsonWriteFeature.COMBINE_UNICODE_SURROGATES_IN_UTF8` is enabled
+ (reported by Justin G)
+ (fixed by @pjfanning)
 
 2.18.0 (26-Sep-2024)
 

src/main/java/com/fasterxml/jackson/core/json/UTF8JsonGenerator.java

@@ -2248,7 +2248,8 @@ private byte[] getHexBytes() {
 
     // @since 2.18
     private static boolean _isStartOfSurrogatePair(final int ch) {
-        return (ch & 0xF800) == 0xD800;
+        // In 0xD800 - 0xDBFF range?
+        return (ch & 0xFC00) == 0xD800;
     }
 }
 

src/test/java/com/fasterxml/jackson/core/json/Surrogate223Test.java → src/test/java/com/fasterxml/jackson/core/write/SurrogateWrite223Test.java

@@ -1,18 +1,19 @@
-package com.fasterxml.jackson.core.json;
+package com.fasterxml.jackson.core.write;
 
 import java.io.ByteArrayOutputStream;
 import java.io.StringWriter;
 import java.io.Writer;
 
 import com.fasterxml.jackson.core.*;
+import com.fasterxml.jackson.core.json.JsonWriteFeature;
 
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-class Surrogate223Test extends JUnit5TestBase
+class SurrogateWrite223Test extends JUnit5TestBase
 {
     private final JsonFactory DEFAULT_JSON_F = newStreamFactory();
 
@@ -92,14 +93,15 @@ void surrogatesCharBacked() throws Exception
         p.close();
     }
 
+    //https://github.com/FasterXML/jackson-core/issues/1359
     @Test
     void checkNonSurrogates() throws Exception {
-        //https://github.com/FasterXML/jackson-core/issues/1359
-        JsonFactory factory = new JsonFactory();
+        JsonFactory f = JsonFactory.builder()
+                .enable(JsonWriteFeature.COMBINE_UNICODE_SURROGATES_IN_UTF8)
+                .build();
         ByteArrayOutputStream out = new ByteArrayOutputStream();
-        try (JsonGenerator gen = factory.createGenerator(out)) {
+        try (JsonGenerator gen = f.createGenerator(out)) {
             gen.writeStartObject();
-            gen.enable(JsonGenerator.Feature.COMBINE_UNICODE_SURROGATES_IN_UTF8);
 
             // Inside the BMP, beyond surrogate block; 0xFF0C - full-width comma
             gen.writeStringField("test_full_width", "foo" + new String(Character.toChars(0xFF0C)) + "bar");