Add parser feature flag to turn on/off tagged array BigDecimal exponent negation, so bug FasterXML#139 fix can be toggled on/off to support backwards compatibility.

Author: msqr

cbor/src/main/java/com/fasterxml/jackson/dataformat/cbor/CBORParser.java

@@ -24,8 +24,15 @@ public class CBORParser extends ParserMinimalBase
      */
     public enum Feature implements FormatFeature
     {
-//        BOGUS(false)
-        ;
+      /**
+       * Feature that can be eanbled to negate a typed array BigDecimal.
+       *<p>
+       * Default provides compatibility with {@code CBORGenerator} from < v2.10.
+       *
+       * @since 2.10.1.SNF
+       */
+      CBOR_BIG_DECIMAL_EXPONENT_NEGATE(false),
+      ;
 
         final boolean _defaultState;
         final int _mask;
@@ -73,6 +80,12 @@ private Feature(boolean defaultState) {
      * Codec used for data binding when (if) requested.
      */
     protected ObjectCodec _objectCodec;
+    
+    /**
+     * Toggle backwards-compatibility with < v2.10 typed array
+     * BigDecimal handling.
+     */
+    final private boolean _bigDecimalNegate;
 
     /*
     /**********************************************************
@@ -366,6 +379,8 @@ public CBORParser(IOContext ctxt, int parserFeatures, int cborFeatures,
 
         _tokenInputRow = -1;
         _tokenInputCol = -1;
+        
+        _bigDecimalNegate = Feature.CBOR_BIG_DECIMAL_EXPONENT_NEGATE.enabledIn(cborFeatures);
     }
 
     @Override
@@ -884,7 +899,7 @@ protected JsonToken _handleTaggedArray(int tag, int len) throws IOException
         // 27-Nov-2019, tatu: As per [dataformats-binary#139] need to change sign here
         //                    if decoding CBOR generated < v2.10
         int exp = getIntValue();
-        if ( exp < 0 ) {
+        if ( _bigDecimalNegate ) {
           exp = -exp;
         }
 

cbor/src/test/java/com/fasterxml/jackson/dataformat/cbor/parse/BigNumbersTest.java

@@ -5,6 +5,7 @@
 import java.math.BigInteger;
 
 import com.fasterxml.jackson.core.JsonToken;
+import com.fasterxml.jackson.dataformat.cbor.CBORFactory;
 import com.fasterxml.jackson.dataformat.cbor.CBORGenerator;
 import com.fasterxml.jackson.dataformat.cbor.CBORParser;
 import com.fasterxml.jackson.dataformat.cbor.CBORTestBase;
@@ -20,10 +21,8 @@ public void testBigDecimalShort() throws Exception
         _testBigDecimal(BigDecimal.ONE.scaleByPowerOfTen(-1));
         _testBigDecimal(BigDecimal.ONE.scaleByPowerOfTen(-3));
         _testBigDecimal(BigDecimal.ONE.scaleByPowerOfTen(-100));
-        /* Disabled for SNF patch
         _testBigDecimal(BigDecimal.ONE.scaleByPowerOfTen(3));
         _testBigDecimal(BigDecimal.ONE.scaleByPowerOfTen(137));
-        */
 
         _testBigDecimal(new BigDecimal("0.01"));
         _testBigDecimal(new BigDecimal("0.33"));
@@ -56,7 +55,9 @@ private void _testBigDecimal(BigDecimal expValue) throws Exception
         byte[] b = sourceBytes.toByteArray();
 
         // but verify that the original content can be parsed
-        CBORParser parser = cborParser(b);
+        final CBORFactory f = new CBORFactory();
+        f.enable(CBORParser.Feature.CBOR_BIG_DECIMAL_EXPONENT_NEGATE);
+        CBORParser parser = cborParser(f, b);
         assertToken(JsonToken.START_OBJECT, parser.nextToken());
         assertToken(JsonToken.FIELD_NAME, parser.nextToken());
         assertEquals("a", parser.getCurrentName());

cbor/src/test/java/com/fasterxml/jackson/dataformat/cbor/parse/ParserNumbersTest.java

@@ -335,7 +335,9 @@ public void testBigDecimalType() throws IOException {
         generator.close();
 
         final byte[] b = out.toByteArray();
-        try (CBORParser parser = cborParser(b)) {
+        CBORFactory f = new CBORFactory();
+        f.enable(CBORParser.Feature.CBOR_BIG_DECIMAL_EXPONENT_NEGATE);
+        try (CBORParser parser = cborParser(f, b)) {
             assertEquals(JsonToken.VALUE_NUMBER_FLOAT, parser.nextToken());
             assertEquals(NumberType.BIG_DECIMAL, parser.getNumberType());
             assertEquals(NR, parser.getDecimalValue());
@@ -354,7 +356,9 @@ public void testBigDecimalType2() throws IOException {
                 0x21,  // int -- -2
                 0x19, 0x6a, (byte) 0xb3 // int 27315
         };
-        try (CBORParser parser = cborParser(spec)) {
+        CBORFactory f = new CBORFactory();
+        f.enable(CBORParser.Feature.CBOR_BIG_DECIMAL_EXPONENT_NEGATE);
+        try (CBORParser parser = cborParser(f, spec)) {
             assertEquals(JsonToken.VALUE_NUMBER_FLOAT, parser.nextToken());
             assertEquals(NumberType.BIG_DECIMAL, parser.getNumberType());
             assertEquals(new BigDecimal("273.15"), parser.getDecimalValue());