Fix #606

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -22,6 +22,7 @@ JSON library.
  (contributed by valery1707@github)
 #587: Add JsonGenerator#writeNumber(char[], int, int) method
  (contributed by Volkan Y)
+#606: Do not clear aggregated contents of `TextBuffer` when `releaseBuffers()` called
 
 2.10.4 (not yet released)
 

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

@@ -219,7 +219,8 @@ protected void _closeInput() throws IOException {
      * separately (if need be).
      */
     @Override
-    protected void _releaseBuffers() throws IOException {
+    protected void _releaseBuffers() throws IOException
+    {
         super._releaseBuffers();
         // merge new symbols, if any
         _symbols.release();
@@ -287,15 +288,14 @@ protected boolean _loadMore() throws IOException
     @Override
     public final String getText() throws IOException
     {
-        JsonToken t = _currToken;
-        if (t == JsonToken.VALUE_STRING) {
+        if (_currToken == JsonToken.VALUE_STRING) {
             if (_tokenIncomplete) {
                 _tokenIncomplete = false;
                 _finishString(); // only strings can be incomplete
             }
             return _textBuffer.contentsAsString();
         }
-        return _getText2(t);
+        return _getText2(_currToken);
     }
 
     @Override // since 2.8

src/main/java/com/fasterxml/jackson/core/json/UTF8StreamJsonParser.java

@@ -274,8 +274,10 @@ protected void _releaseBuffers() throws IOException
             if (buf != null) {
                 // Let's not set it to null; this way should get slightly more meaningful
                 // error messages in case someone closes parser indirectly, without realizing.
-                _inputBuffer = NO_BYTES;
-                _ioContext.releaseReadIOBuffer(buf);
+                if (buf != NO_BYTES) {
+                    _inputBuffer = NO_BYTES;
+                    _ioContext.releaseReadIOBuffer(buf);
+                }
             }
         }
     }

src/main/java/com/fasterxml/jackson/core/util/TextBuffer.java

@@ -150,17 +150,31 @@ public static TextBuffer fromInitial(char[] initialSegment) {
      * can still use this text buffer, it is not advisable to call this
      * method if that is likely, since next time a buffer is needed,
      * buffers need to reallocated.
-     * Note: calling this method automatically also clears contents
-     * of the buffer.
+     *<p>
+     * Note: since Jackson 2.11, calling this method will NOT clear already
+     * aggregated contents (that is, {@code _currentSegment}, to retain
+     * current token text if (but only if!) already aggregated.
      */
     public void releaseBuffers()
     {
-        if (_allocator == null) {
-            resetWithEmpty();
-        } else {
+        // inlined `resetWithEmpty()` (except leaving `_resultString` as-is
+        {
+            _inputStart = -1;
+            _currentSize = 0;
+            _inputLen = 0;
+
+            _inputBuffer = null;
+            // note: _resultString retained (see https://github.com/FasterXML/jackson-databind/issues/2635
+            // for reason)
+            _resultArray = null; // should this be retained too?
+
+            if (_hasSegments) {
+                clearSegments();
+            }
+        }
+
+        if (_allocator != null) {
             if (_currentSegment != null) {
-                // First, let's get rid of all but the largest char array
-                resetWithEmpty();
                 // And then return that array
                 char[] buf = _currentSegment;
                 _currentSegment = null;
@@ -428,6 +442,7 @@ public String contentsAsString()
                 }
             }
         }
+
         return _resultString;
     }