Fix #476

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -16,6 +16,8 @@ JSON library.
 
 2.9.7 (not yet released)
 
+#476: Problem with `BufferRecycler` via async parser (or when sharing parser
+ across threads)
 #477: Exception while decoding Base64 value with escaped `=` character
 
 2.9.6 (12-Jun-2018)

src/main/java/com/fasterxml/jackson/core/JsonFactory.java

@@ -960,7 +960,7 @@ public JsonParser createNonBlockingByteArrayParser() throws IOException
         // 17-May-2017, tatu: Need to take care not to accidentally create JSON parser
         //   for non-JSON input:
         _requireJSONFactory("Non-blocking source not (yet?) support for this format (%s)");
-        IOContext ctxt = _createContext(null, false);
+        IOContext ctxt = _createNonBlockingContext(null);
         ByteQuadsCanonicalizer can = _byteSymbolCanonicalizer.makeChild(_factoryFeatures);
         return new NonBlockingJsonParser(ctxt, _parserFeatures, can);
     }
@@ -1548,6 +1548,19 @@ protected IOContext _createContext(Object srcRef, boolean resourceManaged) {
         return new IOContext(_getBufferRecycler(), srcRef, resourceManaged);
     }
 
+    /**
+     * Overridable factory method that actually instantiates desired
+     * context object for async (non-blocking) parsing
+     *
+     * @since 2.9.7
+     */
+    protected IOContext _createNonBlockingContext(Object srcRef) {
+        // [jackson-core#476]: disable buffer recycling for 2.9 to avoid concurrency issues;
+        // easiest done by just constructing private "recycler":
+        BufferRecycler recycler = new BufferRecycler();
+        return new IOContext(recycler, srcRef, false);
+    }
+
     /**
      * @since 2.8
      */

src/test/java/com/fasterxml/jackson/core/json/async/AsyncConcurrencyTest.java

@@ -96,10 +96,12 @@ private void _assert(JsonToken exp) throws IOException {
         }
     }
 
+    // [jackson-core#476]
     public void testConcurrentAsync() throws Exception
     {
-        for (int i = 0; i < 50; ++i) {
-            _testConcurrentAsyncOnce(i, 50);
+        final int MAX_ROUNDS = 30;
+        for (int i = 0; i < MAX_ROUNDS; ++i) {
+            _testConcurrentAsyncOnce(i, MAX_ROUNDS);
         }
     }