Allow disabling native type ids when deserializing for #270

ion/src/main/java/com/fasterxml/jackson/dataformat/ion/IonFactory.java

@@ -291,15 +291,15 @@ public int getFormatGeneratorFeatures() {
      * @since 2.7
      */
     public IonParser createParser(IonReader in) {
-        return new IonParser(in, _system, _createContext(in, false), getCodec());
+        return new IonParser(in, _system, _createContext(in, false), getCodec(), _ionParserFeatures);
     }
 
     /**
      * @since 2.7
      */
     public IonParser createParser(IonValue value) {
         IonReader in = value.getSystem().newReader(value);
-        return new IonParser(in, _system, _createContext(in, true), getCodec());
+        return new IonParser(in, _system, _createContext(in, true), getCodec(), _ionParserFeatures);
     }
 
     // NOTE! Suboptimal return type -- but can't change safely before 3.0 as return
@@ -324,7 +324,7 @@ public IonSystem getIonSystem() {
      */
     @Deprecated
     public IonParser createJsonParser(IonReader in) {
-        return new IonParser(in, _system, _createContext(in, false), getCodec());
+        return new IonParser(in, _system, _createContext(in, false), getCodec(), _ionParserFeatures);
     }
 
     /**
@@ -333,7 +333,7 @@ public IonParser createJsonParser(IonReader in) {
     @Deprecated
     public IonParser createJsonParser(IonValue value) {
         IonReader in = value.getSystem().newReader(value);
-        return new IonParser(in, _system, _createContext(in, true), getCodec());
+        return new IonParser(in, _system, _createContext(in, true), getCodec(), _ionParserFeatures);
     }
 
     /**
@@ -355,14 +355,14 @@ protected JsonParser _createParser(InputStream in, IOContext ctxt)
         throws IOException
     {
         IonReader ion = _system.newReader(in);
-        return new IonParser(ion, _system, ctxt, getCodec());
+        return new IonParser(ion, _system, ctxt, getCodec(), _ionParserFeatures);
     }
 
     @Override
     protected JsonParser _createParser(Reader r, IOContext ctxt)
         throws IOException
     {
-        return new IonParser(_system.newReader(r), _system, ctxt, getCodec());
+        return new IonParser(_system.newReader(r), _system, ctxt, getCodec(), _ionParserFeatures);
     }
 
     @Override
@@ -376,7 +376,7 @@ protected JsonParser _createParser(char[] data, int offset, int len, IOContext c
     protected JsonParser _createParser(byte[] data, int offset, int len, IOContext ctxt)
         throws IOException
     {
-        return new IonParser(_system.newReader(data, offset, len), _system, ctxt, getCodec());
+        return new IonParser(_system.newReader(data, offset, len), _system, ctxt, getCodec(), _ionParserFeatures);
     }
 
     @Override

ion/src/main/java/com/fasterxml/jackson/dataformat/ion/IonParser.java

@@ -40,6 +40,18 @@ public class IonParser
      */
     public enum Feature implements FormatFeature // in 2.12
     {
+        /**
+         * Whether to expect Ion native Type Id construct for indicating type (true);
+         * or "generic" type property (false) when deserializing.
+         *<p>
+         * Enabled by default for backwards compatibility as that has been the behavior
+         * of `jackson-dataformat-ion` since 2.9 (first official public version)
+         *
+         * @see <a href="https://amzn.github.io/ion-docs/docs/spec.html#annot">The Ion Specification</a>
+         *
+         * @since 2.12.3
+         */
+        USE_NATIVE_TYPE_ID(true),
         ;
 
         final boolean _defaultState;
@@ -113,6 +125,13 @@ private Feature(boolean defaultState) {
      */
     protected JsonToken _valueToken;
 
+    /**
+     * Bit flag composed of bits that indicate which
+     * {@link IonParser.Feature}s
+     * are enabled.
+     */
+    protected int _formatFeatures;
+
     /*
     /*****************************************************************
     /* Construction
@@ -133,15 +152,16 @@ public IonParser(IonReader r, IOContext ctxt)
      */
     @Deprecated
     public IonParser(IonReader r, IOContext ctxt, ObjectCodec codec) {
-        this(r, IonSystemBuilder.standard().build(), ctxt, codec);
+        this(r, IonSystemBuilder.standard().build(), ctxt, codec, IonFactory.DEFAULT_ION_PARSER_FEATURE_FLAGS);
     }
 
-    IonParser(IonReader r, IonSystem system, IOContext ctxt, ObjectCodec codec) {
+    IonParser(IonReader r, IonSystem system, IOContext ctxt, ObjectCodec codec, int ionParserFeatures) {
         this._reader = r;
         this._ioContext = ctxt;
         this._objectCodec = codec;
         this._parsingContext = JsonReadContext.createRootContext(-1, -1, null);
         this._system = system;
+        this._formatFeatures = ionParserFeatures;
     }
 
     @Override
@@ -179,7 +199,9 @@ public IonSystem getIonSystem() {
 
     @Override
     public boolean canReadTypeId() {
-        return true; // yes, Ion got 'em
+        // yes, Ion got 'em
+        // 31-Mar-2021, manaigrn: but we might want to ignore them as per [dataformats-binary#270]
+        return Feature.USE_NATIVE_TYPE_ID.enabledIn(_formatFeatures);
     }
 
     @Override

ion/src/test/java/com/fasterxml/jackson/dataformat/ion/polymorphism/PolymorphicTypeAnnotationsTest.java

@@ -0,0 +1,66 @@
+package com.fasterxml.jackson.dataformat.ion.polymorphism;
+
+import java.io.IOException;
+
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonSubTypes.Type;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.dataformat.ion.IonObjectMapper;
+import com.fasterxml.jackson.dataformat.ion.IonParser.Feature;
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.amazon.ion.IonValue;
+import com.amazon.ion.system.IonSystemBuilder;
+
+public class PolymorphicTypeAnnotationsTest {
+    private static final String SUBCLASS_TYPE_NAME = "subtype";
+
+    @JsonTypeInfo(
+        use = JsonTypeInfo.Id.NAME,
+        include = JsonTypeInfo.As.PROPERTY,
+        property = "base",
+        visible = true
+    )
+    @JsonSubTypes({
+        @Type(value = Subclass.class, name = SUBCLASS_TYPE_NAME),
+    })
+    static public class BaseClass {
+    }
+
+
+    public static class Subclass extends BaseClass {
+        public String base;
+    }
+
+
+    public static class Container {
+        public BaseClass objectWithType;
+    }
+
+
+    private static final IonValue CONTAINER_WITH_TYPED_OBJECT = asIonValue(
+        "{" +
+        "  objectWithType:type::" +
+        "  {" +
+        "    base:\"" + SUBCLASS_TYPE_NAME + "\"," +
+        "  }" +
+        "}");
+
+    @Test
+    public void testNativeTypeIdsDisabledReadsTypeAnnotationsSuccessfully() throws IOException {
+        IonObjectMapper mapper = new IonObjectMapper();
+        mapper.disable(Feature.USE_NATIVE_TYPE_ID);
+
+        Container containerWithBaseClass = mapper.readValue(CONTAINER_WITH_TYPED_OBJECT, Container.class);
+
+        Assert.assertTrue(containerWithBaseClass.objectWithType instanceof Subclass);
+        Assert.assertEquals(SUBCLASS_TYPE_NAME, ((Subclass) containerWithBaseClass.objectWithType).base);
+    }
+
+    private static IonValue asIonValue(final String ionStr) {
+        return IonSystemBuilder.standard()
+            .build()
+            .singleValue(ionStr);
+    }
+}