tweak: get isthmus compiling, throw exception on struct UDTs

Author: benbellick

isthmus/src/main/java/io/substrait/isthmus/expression/CallConverters.java

@@ -70,11 +70,20 @@ public class CallConverters {
               Expression.FixedBinaryLiteral literal = (Expression.FixedBinaryLiteral) operand;
               Type.UserDefined t = (Type.UserDefined) type;
 
-              return Expression.UserDefinedLiteral.builder()
-                  .urn(t.urn())
-                  .name(t.name())
-                  .value(literal.value())
-                  .build();
+              // The binary literal contains the serialized protobuf Any - just parse it directly
+              try {
+                com.google.protobuf.Any anyValue =
+                    com.google.protobuf.Any.parseFrom(literal.value().toByteArray());
+
+                return Expression.UserDefinedAny.builder()
+                    .urn(t.urn())
+                    .name(t.name())
+                    .addAllTypeParameters(t.typeParameters())
+                    .value(anyValue)
+                    .build();
+              } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+                throw new IllegalStateException("Failed to parse UserDefinedAny value", e);
+              }
             }
             return null;
           };

isthmus/src/main/java/io/substrait/isthmus/expression/ExpressionRexConverter.java

@@ -109,14 +109,19 @@ public RexNode visit(Expression.NullLiteral expr, Context context) throws Runtim
   }
 
   @Override
-  public RexNode visit(Expression.UserDefinedLiteral expr, Context context)
-      throws RuntimeException {
+  public RexNode visit(Expression.UserDefinedAny expr, Context context) throws RuntimeException {
     RexLiteral binaryLiteral =
-        rexBuilder.makeBinaryLiteral(new ByteString(expr.value().toByteArray()));
+        rexBuilder.makeBinaryLiteral(new ByteString(expr.value().toByteString().toByteArray()));
     RelDataType type = typeConverter.toCalcite(typeFactory, expr.getType());
     return rexBuilder.makeReinterpretCast(type, binaryLiteral, rexBuilder.makeLiteral(false));
   }
 
+  @Override
+  public RexNode visit(Expression.UserDefinedStruct expr, Context context) throws RuntimeException {
+    throw new UnsupportedOperationException(
+        "UserDefinedStruct representation is not yet supported in Isthmus");
+  }
+
   @Override
   public RexNode visit(Expression.BoolLiteral expr, Context context) throws RuntimeException {
     return rexBuilder.makeLiteral(expr.value());

isthmus/src/test/java/io/substrait/isthmus/CustomFunctionTest.java

@@ -587,7 +587,9 @@ void customTypesInFunctionsRoundtrip() {
   void customTypesLiteralInFunctionsRoundtrip() {
     Builder bldr = Expression.Literal.newBuilder();
     Any anyValue = Any.pack(bldr.setI32(10).build());
-    UserDefinedLiteral val = ExpressionCreator.userDefinedLiteral(false, URN, "a_type", anyValue);
+    UserDefinedLiteral val =
+        ExpressionCreator.userDefinedLiteralAny(
+            false, URN, "a_type", java.util.Collections.emptyList(), anyValue);
 
     Rel rel1 =
         b.project(