Fix four issues flagged in AI code review

- addValueNode: check writeContext.writeValue() return value and report
  error when called in Object context without a preceding property name
- writePropertyId (integer-key path): call writeContext.writeName() to
  keep Jackson write-context state in sync when supportIntegerKeys=true
- MessagePackSerializedString: fix asQuotedUTF8/appendQuotedUTF8/
  writeQuotedUTF8/putQuotedUTF8 to return unquoted UTF-8 bytes;
  SerializableString "quoted" means escaped-not-surrounded-by-quotes,
  and MessagePack has no JSON special characters to escape
- TimestampExtensionModule: wrap IOException as UncheckedIOException
  instead of plain RuntimeException to preserve the IO failure type

Author: komamitsu

msgpack-jackson3/src/main/java/org/msgpack/jackson/dataformat/MessagePackGenerator.java

@@ -470,7 +470,9 @@ private void addKeyNode(Object key)
 
     private void addValueNode(Object value) throws IOException
     {
-        writeContext.writeValue();
+        if (!writeContext.writeValue()) {
+            _reportError("Cannot write value: expecting a property name in Object context");
+        }
         switch (currentState) {
             case IN_OBJECT: {
                 Node node = nodes.get(nodes.size() - 1);
@@ -509,6 +511,9 @@ private void writeByteArrayTextValue(byte[] text, int offset, int len) throws IO
     public JsonGenerator writePropertyId(long id) throws JacksonException
     {
         if (this.supportIntegerKeys) {
+            if (!writeContext.writeName(String.valueOf(id))) {
+                _reportError("Cannot write property name, not in Object context");
+            }
             addKeyNode(id);
         }
         else {

msgpack-jackson3/src/main/java/org/msgpack/jackson/dataformat/MessagePackSerializedString.java

@@ -61,13 +61,13 @@ public byte[] asUnquotedUTF8()
     @Override
     public byte[] asQuotedUTF8()
     {
-        return ("\"" + getValue() + "\"").getBytes(UTF8);
+        return asUnquotedUTF8();
     }
 
     @Override
     public int appendQuotedUTF8(byte[] bytes, int i)
     {
-        byte[] utf8 = asQuotedUTF8();
+        byte[] utf8 = asUnquotedUTF8();
         System.arraycopy(utf8, 0, bytes, i, utf8.length);
         return utf8.length;
     }
@@ -100,7 +100,7 @@ public int appendUnquoted(char[] chars, int i)
     public int writeQuotedUTF8(OutputStream outputStream)
     {
         try {
-            byte[] utf8 = asQuotedUTF8();
+            byte[] utf8 = asUnquotedUTF8();
             outputStream.write(utf8);
             return utf8.length;
         }
@@ -125,7 +125,7 @@ public int writeUnquotedUTF8(OutputStream outputStream)
     @Override
     public int putQuotedUTF8(ByteBuffer byteBuffer)
     {
-        byte[] utf8 = asQuotedUTF8();
+        byte[] utf8 = asUnquotedUTF8();
         byteBuffer.put(utf8);
         return utf8.length;
     }

msgpack-jackson3/src/main/java/org/msgpack/jackson/dataformat/TimestampExtensionModule.java

@@ -14,6 +14,7 @@
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.time.Instant;
 
 public class TimestampExtensionModule
@@ -50,7 +51,7 @@ public void serialize(Instant value, JsonGenerator gen, SerializationContext pro
                 }
             }
             catch (IOException e) {
-                throw new RuntimeException(e);
+                throw new UncheckedIOException(e);
             }
         }
     }
@@ -77,7 +78,7 @@ public Instant deserialize(JsonParser p, DeserializationContext ctxt)
                 }
             }
             catch (IOException e) {
-                throw new RuntimeException(e);
+                throw new UncheckedIOException(e);
             }
         }
     }