Backport #80 into 2.7.9, 2.8.6

Author: cowtowncoder

release-notes/CREDITS

@@ -48,3 +48,7 @@ James Baker (j-baker@github)
   Jackson-annotated class itself deserialises a Jackson-annotated class
  (2.7.8)
 
+Tanguy Leroux (tlrx@github)
+
+- Reported, contributed test, fix for #80: Fix UTF8Writer when used in same thread
+ (2.7.9)

release-notes/VERSION

@@ -8,6 +8,11 @@ Project: jackson-dataformat-yaml
 
 No changes since 2.7
 
+2.7.9 (not yet released)
+
+#80: Fix UTF8Writer when used in same thread
+ (contributed by Tanguy L)
+
 2.7.8 (26-Sep-2016)
 
 #70: `UTF8Reader` is unsafe if a Jackson-annotated class itself deserializes

src/main/java/com/fasterxml/jackson/dataformat/yaml/UTF8Writer.java

@@ -43,7 +43,7 @@ public UTF8Writer(OutputStream out)
         _bufferHolder = _findBufferHolder();
         byte[] buffer = _bufferHolder[0];
         if (buffer == null) {
-            _bufferHolder[0] = buffer = new byte[DEFAULT_BUFFER_SIZE];
+            buffer = new byte[DEFAULT_BUFFER_SIZE];
         } else {
             _bufferHolder[0] = null;
         }