Deserializing BigDecimal using JsonNode loses precision

Using jackson-databind 2.9.6

There seems to be an issue parsing BigDecimals as JsonNodes where it is forced to pass though an intermediate phase as a double and precision is destroyed

The code below illustrates the issue - on the original BigDecimal the precision is 2, after deserializing the precision is 1. If the custom Deserializer is disabled then the test passes.

import java.io.IOException;
import java.math.BigDecimal;

import org.junit.jupiter.api.Test;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;

class SimpleTest {

	@Test
	void test() throws JsonParseException, JsonMappingException, IOException {
		TestClass z = new TestClass();
		z.setA(new BigDecimal("0.0060"));
		
		ObjectMapper m = new ObjectMapper();
        m.configure(DeserializationFeature.USE_BIG_DECIMAL_FOR_FLOATS, true);
		String s = m.writeValueAsString(z);
		System.out.println(s);
		
		TestClass readValue = m.readValue(s, TestClass.class);
		System.out.println(readValue.getA());
		assertEquals(z.a.precision(), readValue.a.precision());
	}
	
	static class DeSer extends StdDeserializer<TestClass> {

		public DeSer() {
			super(TestClass.class);
		}

		@Override
		public TestClass deserialize(JsonParser jp, DeserializationContext ctxt)
				throws IOException, JsonProcessingException {
			JsonNode node = jp.getCodec().readTree(jp);
			System.out.println(node.toString());
			ObjectMapper m = new ObjectMapper();
			BigDecimal bd = m.treeToValue(node.get("a"), BigDecimal.class);
			TestClass testClass = new TestClass();
			testClass.setA(bd);
			return testClass;
		}
		
	}

	@JsonDeserialize(using = DeSer.class)
	static class TestClass {
		BigDecimal a;

		public BigDecimal getA() {
			return a;
		}

		public void setA(BigDecimal a) {
			this.a = a;
		}
		
	}
}```

[cowtowncoder]

@ymenager Please do tell me how I use my free time. I really like hearing FUCKING DEMANDS FROM YOU, A PERSON I DON’T EVEN KNOW.

Actually, fuck you. Go away.

[CowboyCodingRules]

@cowtowncoder Do you need a hug?