fix: handle edge case where a null array was provided

Author: vaadata-pascala

build.gradle

@@ -3,7 +3,7 @@ plugins {
 }
 
 group = 'sh.arnaud'
-version = '1.0.1-SNAPSHOT'
+version = '1.0.2-SNAPSHOT'
 
 repositories {
     mavenCentral()

src/main/java/sh/arnaud/javaserde/codec/Decoder.java

@@ -116,7 +116,15 @@ private GrammarNewEnum readNewEnum(ByteBuffer data) throws Exception {
     }
 
     private GrammarNewArray readNewArray(ByteBuffer data) throws Exception {
-        if (peekByte(data) == TC_REFERENCE) {
+        var peeked = peekByte(data);
+
+        if (peeked == TC_NULL) {
+            data.get();
+
+            return null;
+        }
+
+        if (peeked == TC_REFERENCE) {
             data.get();
 
             return handles.retrieve(data.getInt(), GrammarNewArray.class);

src/main/java/sh/arnaud/javaserde/codec/Encoder.java

@@ -64,7 +64,7 @@ private void writeContent(GrammarContent content) throws Exception {
             return;
         }
 
-        throw new UnsupportedOperationException("Serialization of content not implemented yet!");
+        throw new UnsupportedOperationException("Serialization of content not implemented yet: ".concat(content.getClass().getName()));
     }
 
     private void referenceable(GrammarObject object, Callable<Void> runnable) throws Exception {
@@ -105,6 +105,11 @@ private void writeNewEnum(GrammarNewEnum newEnum) throws Exception {
 
     private void writeNewArray(GrammarNewArray array) throws Exception {
         referenceable(array, () -> {
+            if (array == null) {
+                buffer.writeByte(TC_NULL);
+                return null;
+            }
+
             buffer.writeByte(TC_ARRAY);
             writeClassDesc(array.classDesc);
 

src/test/resources/sh/arnaud/javaserde/units/009-nullable/Generator.java

@@ -0,0 +1,20 @@
+import java.io.*;
+import java.util.Date;
+
+public class Nullable implements Serializable {
+	enum Enum {
+		ONE,
+		TWO
+	}
+
+	private final String null_string = null;
+	private final int[] null_ints = null;
+	private final Enum null_enum = null;
+
+	public static void main(String args[]) throws Exception {
+		var stream = new ObjectOutputStream(System.out);
+
+		stream.writeObject(new Nullable());
+		stream.flush();
+	}
+}

src/test/resources/sh/arnaud/javaserde/units/009-nullable/stream.bin

@@ -0,0 +1,37 @@
+[
+  {
+    "@handle": 8257540,
+    "@class": {
+      "@handle": 8257536,
+      "@name": "Nullable",
+      "@serial": 9613321951376902,
+      "@flags": 2,
+      "@fields": [
+        {
+          "@name": "null_enum",
+          "@type": "LNullable$Enum;"
+        },
+        {
+          "@name": "null_ints",
+          "@type": "[I"
+        },
+        {
+          "@name": "null_string",
+          "@type": "Ljava/lang/String;"
+        }
+      ],
+      "@annotations": [],
+      "@super": null
+    },
+    "@data": [
+      {
+        "@values": [
+          null,
+          null,
+          null
+        ],
+        "@annotations": []
+      }
+    ]
+  }
+]