Addressing review comments

incubator/catalog-schema-registry/src/main/java/io/aklivity/zilla/runtime/catalog/schema/registry/internal/SchemaRegistryCatalogHandler.java

@@ -190,7 +190,7 @@ public int encode(
         SchemaRegistryPrefixFW prefix = prefixRW.rewrap().schemaId(schemaId).build();
         next.accept(prefix.buffer(), prefix.offset(), prefix.sizeof());
         int valLength = encoder.accept(schemaId, data, index, length, next);
-        return valLength != 0 ? prefix.sizeof() + valLength : -1;
+        return valLength > 0 ? prefix.sizeof() + valLength : -1;
     }
 
     @Override

incubator/validator-protobuf/src/main/java/io/aklivity/zilla/runtime/validator/protobuf/DescriptorTree.java

@@ -76,7 +76,7 @@ protected DescriptorTree findByName(
         return current;
     }
 
-    protected DescriptorTree findByIndexes(
+    protected Descriptor findByIndexes(
         List<Integer> indexes)
     {
         DescriptorTree current = this;
@@ -86,10 +86,10 @@ protected DescriptorTree findByIndexes(
             current = current.findChild(index);
             if (current == null)
             {
-                return null;
+                break;
             }
         }
-        return current;
+        return current != null ? current.descriptor : null;
     }
 
     private DescriptorTree findParent(

incubator/validator-protobuf/src/main/java/io/aklivity/zilla/runtime/validator/protobuf/ProtobufReadValidator.java

@@ -63,14 +63,9 @@ public int padding(
 
             if (schemaId == NO_SCHEMA_ID)
             {
-                if (catalog.id != NO_SCHEMA_ID)
-                {
-                    schemaId = catalog.id;
-                }
-                else
-                {
-                    schemaId = handler.resolve(subject, catalog.version);
-                }
+                schemaId = catalog.id != NO_SCHEMA_ID
+                    ? catalog.id
+                    : handler.resolve(subject, catalog.version);
             }
             padding = supplyJsonFormatPadding(schemaId);
         }
@@ -144,17 +139,15 @@ private int validate(
         DescriptorTree tree = supplyDescriptorTree(schemaId);
         if (tree != null)
         {
-            tree = tree.findByIndexes(indexes);
-            if (tree != null)
+            Descriptors.Descriptor descriptor = tree.findByIndexes(indexes);
+            if (descriptor != null)
             {
-                Descriptors.Descriptor descriptor = tree.descriptor;
                 in.wrap(data, index, length);
                 DynamicMessage.Builder builder = supplyDynamicMessageBuilder(descriptor);
                 validate:
                 try
                 {
-                    builder.mergeFrom(in);
-                    DynamicMessage message = builder.build();
+                    DynamicMessage message = builder.mergeFrom(in).build();
                     builder.clear();
                     if (!message.getUnknownFields().asMap().isEmpty())
                     {
@@ -175,9 +168,9 @@ private int validate(
                         valLength = length;
                     }
                 }
-                catch (IOException e)
+                catch (IOException ex)
                 {
-                    e.printStackTrace();
+                    ex.printStackTrace();
                 }
             }
         }

incubator/validator-protobuf/src/main/java/io/aklivity/zilla/runtime/validator/protobuf/ProtobufValidator.java

@@ -37,8 +37,6 @@
 import com.google.protobuf.Descriptors.DescriptorValidationException;
 import com.google.protobuf.Descriptors.FileDescriptor;
 import com.google.protobuf.DynamicMessage;
-import com.google.protobuf.InvalidProtocolBufferException;
-import com.google.protobuf.util.JsonFormat;
 
 import io.aklivity.zilla.runtime.engine.catalog.CatalogHandler;
 import io.aklivity.zilla.runtime.engine.config.CatalogedConfig;
@@ -49,9 +47,12 @@
 
 public class ProtobufValidator
 {
-    protected static final byte ZERO_INDEX = 0x0;
+    protected static final byte[] ZERO_INDEX = new byte[]{0x0};
     protected static final String FORMAT_JSON = "json";
 
+    private static final int JSON_FIELD_STRUCTURE_LENGTH = "\"\":\"\",".length();
+    private static final int JSON_OBJECT_CURLY_BRACES = 2;
+
     protected final SchemaConfig catalog;
     protected final CatalogHandler handler;
     protected final String subject;
@@ -213,13 +214,13 @@ private int calculateJsonFormatPadding(
 
         if (descriptor != null)
         {
-            try
-            {
-                padding = 2 + JsonFormat.printer().print(descriptor.toProto()).length();
-            }
-            catch (InvalidProtocolBufferException e)
+            for (Descriptors.Descriptor message : descriptor.getMessageTypes())
             {
-                e.printStackTrace();
+                padding += JSON_OBJECT_CURLY_BRACES;
+                for (Descriptors.FieldDescriptor field : message.getFields())
+                {
+                    padding += field.getName().getBytes().length + JSON_FIELD_STRUCTURE_LENGTH;
+                }
             }
 
         }
@@ -249,9 +250,9 @@ private FileDescriptor createDescriptors(
             {
                 descriptor = FileDescriptor.buildFrom(listener.build(), dependencies);
             }
-            catch (DescriptorValidationException e)
+            catch (DescriptorValidationException ex)
             {
-                e.printStackTrace();
+                ex.printStackTrace();
             }
         }
         return descriptor;

incubator/validator-protobuf/src/main/java/io/aklivity/zilla/runtime/validator/protobuf/ProtobufWriteValidator.java

@@ -130,14 +130,13 @@ private boolean validate(
                 DynamicMessage.Builder builder = supplyDynamicMessageBuilder(descriptor);
                 try
                 {
-                    builder.mergeFrom(in);
-                    DynamicMessage message = builder.build();
+                    DynamicMessage message = builder.mergeFrom(in).build();
                     builder.clear();
                     status = message.getUnknownFields().asMap().isEmpty();
                 }
-                catch (IOException e)
+                catch (IOException ex)
                 {
-                    e.printStackTrace();
+                    ex.printStackTrace();
                 }
             }
         }
@@ -151,10 +150,10 @@ private int encode(
         int length,
         ValueConsumer next)
     {
-        int valLength = 0;
+        int valLength = -1;
         if (indexes.size() == 2 && indexes.get(0) == 1 && indexes.get(1) == 0)
         {
-            indexesRO.wrap(new byte[]{ZERO_INDEX});
+            indexesRO.wrap(ZERO_INDEX);
             valLength = 1;
         }
         else
@@ -183,6 +182,7 @@ private int serializeJsonRecord(
             if (tree != null)
             {
                 Descriptors.Descriptor descriptor = tree.descriptor;
+                indexes.clear();
                 indexes.add(tree.indexes.size());
                 indexes.addAll(tree.indexes);
                 DynamicMessage.Builder builder = supplyDynamicMessageBuilder(descriptor);
@@ -199,9 +199,9 @@ private int serializeJsonRecord(
                         valLength = encode(schemaId, out.buffer(), 0, out.position(), next);
                     }
                 }
-                catch (IOException e)
+                catch (IOException ex)
                 {
-                    e.printStackTrace();
+                    ex.printStackTrace();
                 }
             }
         }

incubator/validator-protobuf/src/test/java/io/aklivity/zilla/runtime/validator/protobuf/ProtobufValidatorTest.java

@@ -351,7 +351,7 @@ public void shouldVerifyJsonFormatPaddingLength()
 
         DirectBuffer data = new UnsafeBuffer();
 
-        assertEquals(1584, validator.padding(data, 0, data.capacity()));
+        assertEquals(71, validator.padding(data, 0, data.capacity()));
     }
 
     @Test