Issue#661 Always return a valid BitSet type

.gitignore

@@ -101,6 +101,7 @@ csharp/sbe-generated/extension
 csharp/sbe-generated/issue435
 csharp/sbe-generated/issue483
 csharp/sbe-generated/issue560
+csharp/sbe-generated/issue661
 csharp/sbe-generated/since-deprecated
 csharp/sbe-generated/mktdata/*.cs
 csharp/sbe-generated/uk_co_real_logic_sbe_benchmarks_fix

build.gradle

@@ -656,6 +656,7 @@ task generateGolangCodecsWithXSD(type: JavaExec) {
             'sbe-tool/src/test/resources/issue483.xml',
             'sbe-tool/src/test/resources/issue488.xml',
             'sbe-tool/src/test/resources/issue560.xml',
+            'sbe-tool/src/test/resources/issue661.xml',
             'sbe-tool/src/test/resources/since-deprecated-test-schema.xml',
             'sbe-tool/src/test/resources/example-bigendian-test-schema.xml',
             'gocode/resources/example-composite.xml',

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/csharp/CSharpGenerator.java

@@ -35,7 +35,6 @@
 import static uk.co.real_logic.sbe.ir.GenerationUtil.collectGroups;
 import static uk.co.real_logic.sbe.ir.GenerationUtil.collectFields;
 
-@SuppressWarnings("MethodLength")
 public class CSharpGenerator implements CodeGenerator
 {
     private static final String META_ATTRIBUTE_ENUM = "MetaAttribute";
@@ -358,7 +357,6 @@ private CharSequence generateVarData(final List<Token> tokens, final String inde
                     indent + "public const int %sHeaderSize = %d;\n",
                     propertyName,
                     sizeOfLengthField));
-
                 sb.append(String.format(indent + "\n" +
                     indent + "public int %1$sLength()\n" +
                     indent + "{\n" +
@@ -369,12 +367,10 @@ private CharSequence generateVarData(final List<Token> tokens, final String inde
                     sizeOfLengthField,
                     lengthTypePrefix,
                     byteOrderStr));
-
                 sb.append(String.format("\n" +
                     indent + "public int Get%1$s(byte[] dst, int dstOffset, int length) =>\n" +
                     indent + INDENT + "Get%1$s(new Span<byte>(dst, dstOffset, length));\n",
                     propertyName));
-
                 sb.append(String.format("\n" +
                     indent + "public int Get%1$s(Span<byte> dst)\n" +
                     indent + "{\n" +
@@ -393,7 +389,6 @@ private CharSequence generateVarData(final List<Token> tokens, final String inde
                     sizeOfLengthField,
                     lengthTypePrefix,
                     byteOrderStr));
-
                 sb.append(String.format(indent + "\n" +
                     indent + "// Allocates and returns a new byte array\n" +
                     indent + "public byte[] Get%1$sBytes()\n" +
@@ -412,12 +407,10 @@ private CharSequence generateVarData(final List<Token> tokens, final String inde
                     sizeOfLengthField,
                     lengthTypePrefix,
                     byteOrderStr));
-
                 sb.append(String.format("\n" +
                     indent + "public int Set%1$s(byte[] src, int srcOffset, int length) =>\n" +
                     indent + INDENT + "Set%1$s(new ReadOnlySpan<byte>(src, srcOffset, length));\n",
                     propertyName));
-
                 sb.append(String.format("\n" +
                     indent + "public int Set%1$s(ReadOnlySpan<byte> src)\n" +
                     indent + "{\n" +
@@ -499,7 +492,7 @@ private CharSequence generateCompositePropertyElements(final List<Token> tokens,
             final Token token = tokens.get(i);
             final String propertyName = formatPropertyName(token.name());
 
-            // FIXME: do I need to pass class name down here for disambiguation
+            // FIXME: do I need to pass classname down here for disambiguation
             switch (token.signal())
             {
                 case ENCODING:
@@ -765,6 +758,22 @@ private CharSequence generateArrayFieldNotPresentCondition(
             sinceVersion);
     }
 
+    private CharSequence generateBitSetNotPresentCondition(
+        final int sinceVersion,
+        final String indent,
+        final String bitSetName)
+    {
+        if (0 == sinceVersion)
+        {
+            return "";
+        }
+
+        return String.format(
+            indent + INDENT + INDENT + INDENT + "if (_actingVersion < %1$d) return (%2$s)0;\n\n",
+            sinceVersion,
+            bitSetName);
+    }
+
     private CharSequence generateTypeFieldNotPresentCondition(
         final int sinceVersion,
         final String indent)
@@ -1223,7 +1232,7 @@ private String generateBitSetProperty(final String propertyName, final Token tok
             indent + INDENT + "}\n",
             bitSetName,
             toUpperFirstChar(propertyName),
-            generateTypeFieldNotPresentCondition(token.version(), indent),
+            generateBitSetNotPresentCondition(token.version(), indent, bitSetName),
             bitSetName,
             typePrefix,
             offset,

sbe-tool/src/test/resources/issue661.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<sbe:messageSchema xmlns:sbe="http://fixprotocol.io/2016/sbe"
+                   package="issue661"
+                   id="661"
+                   version="1"
+                   semanticVersion="1.0"
+                   description="issue 661 test case"
+                   byteOrder="bigEndian">
+    <types>
+        <set name="set" encodingType="uint8">
+            <choice name="One">0</choice>
+            <choice name="Two">1</choice>
+        </set>
+        <composite name="messageHeader" description="Message identifiers and length of message root">
+            <type name="blockLength" primitiveType="uint16"/>
+            <type name="templateId" primitiveType="uint16"/>
+            <type name="schemaId" primitiveType="uint16"/>
+            <type name="version" primitiveType="uint16"/>
+        </composite>
+    </types>
+    <sbe:message name="issue661" id="1" description="issue 661 test">
+	<field name="set0" type="set" id="10"/>
+	<field name="set1" type="set" id="11" sinceVersion="1"/>
+    </sbe:message>
+</sbe:messageSchema>