Last part of clean up wrt Avro fixes

Author: cowtowncoder

avro/src/main/java/com/fasterxml/jackson/dataformat/avro/AvroGenerator.java

@@ -381,7 +381,7 @@ public final void writeEndArray() throws IOException
 
     @Override
     public final void writeStartObject() throws IOException {
-        _avroContext = _avroContext.createChildObjectContext();
+        _avroContext = _avroContext.createChildObjectContext(null);
         _complete = false;
     }
 

avro/src/main/java/com/fasterxml/jackson/dataformat/avro/ser/AvroWriteContext.java

@@ -73,10 +73,6 @@ public static AvroWriteContext nullContext() {
 
     public abstract AvroWriteContext createChildArrayContext(Object currValue) throws JsonMappingException;
 
-    public AvroWriteContext createChildObjectContext() throws JsonMappingException {
-        return createChildObjectContext(null);
-    }
-
     public abstract AvroWriteContext createChildObjectContext(Object currValue) throws JsonMappingException;
 
     public void complete() throws IOException {
@@ -211,23 +207,33 @@ protected GenericArray<Object> _createArray(Schema schema)
         return new GenericData.Array<Object>(8, schema);
     }
 
+    // Removed from 2.10, should not be needed any more
+    /*
     protected AvroWriteContext _createObjectContext(Schema schema) throws JsonMappingException {
         if (schema.getType() == Type.UNION) {
             schema = _recordOrMapFromUnion(schema);
         }
         return _createObjectContext(schema, null); // Object doesn't matter as long as schema isn't a union
     }
+    */
 
     protected AvroWriteContext _createObjectContext(Schema schema, Object currValue)
             throws JsonMappingException
     {
         Type type = schema.getType();
         if (type == Schema.Type.UNION) {
-            try {
-                schema = resolveUnionSchema(schema, currValue);
-            } catch (UnresolvedUnionException e) {
-                // couldn't find an exact match
+            // 14-Aug-2019, tatu: Mapping null is bit special; and without special handling
+            //   we get an exception after fix for [dataformats-binary#168]
+            //  ... but I am not sure I fully understand what or why, actually.
+            if (currValue == null) {
                 schema = _recordOrMapFromUnion(schema);
+            } else {
+                try {
+                    schema = resolveUnionSchema(schema, currValue);
+                } catch (UnresolvedUnionException e) {
+                    // couldn't find an exact match
+                    schema = _recordOrMapFromUnion(schema);
+                }
             }
             type = schema.getType();
         }

avro/src/main/java/com/fasterxml/jackson/dataformat/avro/ser/ObjectWriteContext.java

@@ -47,18 +47,6 @@ public final AvroWriteContext createChildArrayContext(Object currValue)
         return child;
     }
 
-    @Override
-    public AvroWriteContext createChildObjectContext() throws JsonMappingException {
-        _verifyValueWrite();
-        Schema.Field field = _findField();
-        if (field == null) { // unknown, to ignore
-            return new NopWriteContext(TYPE_OBJECT, this, _generator, null);
-        }
-        AvroWriteContext child = _createObjectContext(field.schema());
-        _record.put(_currentName, child.rawValue());
-        return child;
-    }
-
     @Override
     public AvroWriteContext createChildObjectContext(Object currValue) throws JsonMappingException {
         _verifyValueWrite();

cbor/src/test/java/com/fasterxml/jackson/dataformat/cbor/GeneratorDeepNestingTest.java

@@ -1,7 +1,6 @@
 package com.fasterxml.jackson.dataformat.cbor;
 
 import java.io.ByteArrayOutputStream;
-import java.io.OutputStream;
 import java.util.*;
 
 import com.fasterxml.jackson.core.JsonGenerator;