Add support for compact enum with fields (#3873)

tests/ZeroC.Slice.Tests/EnumWithFieldsTests.cs

@@ -23,6 +23,9 @@ public void Decode_enum_ignores_unknown_tagged_fields()
         // Assert
         Assert.That(decoded, Is.InstanceOf(typeof(Color.Blue)));
         Assert.That(decoder.Consumed, Is.EqualTo(encoder.EncodedByteCount));
+
+        // 1 for the discriminant, 1 for the tag, 1 for the tagged value size, 2 for code, 1 for the tag end marker
+        Assert.That(decoder.Consumed, Is.EqualTo(1 + 1 + 1 + 2 + 1));
     }
 
     [TestCase("canary", (ushort)7)]
@@ -112,6 +115,56 @@ public void Decode_enum_with_optional_field(string? name, uint major, uint minor
         Assert.That(decoder.Consumed, Is.EqualTo(encoder.EncodedByteCount));
     }
 
+    [Test]
+    public void Decode_compact_enum()
+    {
+         // Arrange
+        var buffer = new MemoryBufferWriter(new byte[256]);
+        var encoder = new SliceEncoder(buffer, SliceEncoding.Slice2);
+        var shape = new CompactShape.Rectangle(10, 20);
+        encoder.EncodeCompactShape(shape);
+
+        var decoder = new SliceDecoder(buffer.WrittenMemory, SliceEncoding.Slice2);
+
+        // Act
+        var decoded = decoder.DecodeCompactShape();
+
+        // Assert
+        Assert.That(decoded, Is.EqualTo(shape));
+        Assert.That(decoder.Consumed, Is.EqualTo(encoder.EncodedByteCount));
+    }
+
+    [TestCase("foo", 8u, 4u)]
+    [TestCase(null, 7u, 3u)]
+    public void Decode_compact_enum_with_optional_field(string? name, uint major, uint minor)
+    {
+         // Arrange
+        var buffer = new MemoryBufferWriter(new byte[256]);
+        var encoder = new SliceEncoder(buffer, SliceEncoding.Slice2);
+        var shape = new CompactShape.Oval(name, major, minor);
+        encoder.EncodeCompactShape(shape);
+
+        var decoder = new SliceDecoder(buffer.WrittenMemory, SliceEncoding.Slice2);
+
+        // Act
+        var decoded = decoder.DecodeCompactShape();
+
+        // Assert
+        Assert.That(decoded, Is.EqualTo(shape));
+        Assert.That(decoder.Consumed, Is.EqualTo(encoder.EncodedByteCount));
+        if (name is null)
+        {
+            // 1 for the discriminant, 1 for the bit sequence, 4 for major, 4 for minor
+            Assert.That(decoder.Consumed, Is.EqualTo(1 + 1 + 4 + 4));
+        }
+        else
+        {
+            // 1 for the discriminant, 1 for the bit sequence, 1 for the name length (assuming small length),
+            // name.Length bytes (assuming ASCII), 4 for major, 4 for minor
+            Assert.That(decoder.Consumed, Is.EqualTo(1 + 1 + 1 + name.Length + 4 + 4));
+        }
+    }
+
     [Test]
     public void Enumerator_with_fields_gets_attribute() =>
         Assert.That(typeof(ShapeWithAttribute.Rectangle).GetSliceTypeId(), Is.EqualTo("MyRectangle"));

tests/ZeroC.Slice.Tests/EnumWithFieldsTests.slice

@@ -26,6 +26,13 @@ unchecked enum RevisedShape {
     Oval(name: string?, major: uint32, minor: uint32)
 }
 
+compact enum CompactShape {
+    Circle(radius: uint32)
+    Rectangle(width: uint32, height: uint32)
+    Triangle(side1: uint32, side2: uint32, side3: uint32)
+    Oval(name: string?, major: uint32, minor: uint32)
+}
+
 enum ShapeWithAttribute {
     [cs::attribute("SliceTypeId(\"MyCircle\")")]
     Circle(radius: uint32)

tools/slicec-cs/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "slicec-cs"
-version = "0.2.0"
+version = "0.3.0-preview1"
 authors = ["ZeroC Inc."]
 description = """
 The slicec-cs compiler, for compiling Slice files into C# code.
@@ -14,7 +14,7 @@ rust-version = "1.70"
 clap = { version = "4.3.15", features = ["derive"] }
 convert_case = "0.6.0"
 in_definite = "1.0.0"
-slicec = "0.2.1"
+slicec = { git = "https://github.com/icerpc/slicec", rev = "afba8cf1cde99fdbf475aa2839c08866076d8e77" }
 
 [dev-dependencies]
 test-case = "3.3.1"

tools/slicec-cs/src/generators/enum_generator.rs

@@ -133,7 +133,7 @@ fn enumerators_as_nested_records(enum_def: &Enum) -> CodeBlock {
             .add_comments(enumerator.formatted_doc_comment_seealso())
             .add_obsolete_attribute(enumerator)
             .add_base(enum_def.escape_identifier())
-            .add_fields(&enumerator.associated_fields().unwrap_or_default());
+            .add_fields(&enumerator.fields());
 
         // Add cs::attribute
         for attribute in enumerator.cs_attributes() {
@@ -159,9 +159,7 @@ fn enumerators_as_nested_records(enum_def: &Enum) -> CodeBlock {
                     code.writeln("encoder.EncodeVarInt32(Discriminant);");
 
                     if enum_def.is_unchecked {
-                        // TODO: oddly enough, an enumerator declared as E() or E does not result in the same
-                        // associated fields.
-                        if enumerator.associated_fields().unwrap_or_default().is_empty() {
+                        if enumerator.fields().is_empty() {
                             // For the tag end marker. This assumes an unchecked enum with associated fields is never
                             // compact.
                             code.writeln("encoder.EncodeSize(1);");
@@ -172,16 +170,17 @@ fn enumerators_as_nested_records(enum_def: &Enum) -> CodeBlock {
                     }
 
                     code.writeln(&encode_fields(
-                        &enumerator.associated_fields().unwrap_or_default(),
+                        &enumerator.fields(),
                         &namespace,
                         FieldType::NonMangled,
                         Encoding::Slice2,
                     ));
 
-                    // TODO: only for non-compact enum
-                    code.writeln("encoder.EncodeVarInt32(Slice2Definitions.TagEndMarker);");
+                    if !enum_def.is_compact {
+                        code.writeln("encoder.EncodeVarInt32(Slice2Definitions.TagEndMarker);");
+                    }
 
-                    if enum_def.is_unchecked && !enumerator.associated_fields().unwrap_or_default().is_empty() {
+                    if enum_def.is_unchecked && !enumerator.fields().is_empty() {
                         code.writeln("SliceEncoder.EncodeVarUInt62((ulong)(encoder.EncodedByteCount - startPos), sizePlaceholder);");
                     }
 
@@ -520,15 +519,16 @@ fn enum_decoder_extensions(enum_def: &Enum) -> CodeBlock {
                         }
 
                         code.writeln(&decode_enum_fields(
-                            &enumerator.associated_fields().unwrap_or_default(),
+                            &enumerator.fields(),
                             &decoded_type,
                             &namespace,
                             FieldType::NonMangled,
                             Encoding::Slice2,
                         ));
 
-                        // TODO: only for non-compact enum
-                        code.writeln("decoder.SkipTagged();");
+                        if !enum_def.is_compact {
+                            code.writeln("decoder.SkipTagged();");
+                        }
 
                         code.writeln("return result;");
                         code