Inconsistent behavior deserializing boxed and collections of Double when the input contains no decimal

[joshuaprince]

Describe the bug
ConfigLib handles reading and loading Doubles without a decimal point a bit inconsistently depending on whether they are primitive, boxed, or part of a collection.

To Reproduce
Here's a complete set of tests that show the inconsistent behavior:

    // YamlConfigurationsTest.java
    @Configuration
    private static final class DoublesConfig {
        double d;
        Double boxed;
        List<Double> list;
    }

    @Test // 1
    void loadYamlConfigurationDoublesAllDecimal() {
        writeStringToFile("d: 10.0\nboxed: 20.0\nlist:\n  - 1.0\n  - 2.0\n  - 3.0\n");
        DoublesConfig config = YamlConfigurations.load(yamlFile, DoublesConfig.class);
        assertEquals(10.0, config.d);
        assertEquals(20.0, config.boxed);
        assertEquals(List.of(1.0, 2.0, 3.0), config.list); // PASSES
    }

    @Test // 2
    void loadYamlConfigurationDoublesUnboxed() {
        writeStringToFile("d: 10");
        DoublesConfig config = YamlConfigurations.load(yamlFile, DoublesConfig.class);
        assertEquals(10.0, config.d); // PASSES
    }

    @Test // 3
    void loadYamlConfigurationDoublesBoxed() {
        writeStringToFile("boxed: 20");
        DoublesConfig config = YamlConfigurations.load(yamlFile, DoublesConfig.class); // FAILS HERE
        assertEquals(20.0, config.boxed);
    }

    @Test // 4
    void loadYamlConfigurationDoublesCollection() {
        writeStringToFile("list:\n  - 1.0\n  - 2\n  - 3.0\n"); // 2.0 -> 2
        DoublesConfig config = YamlConfigurations.load(yamlFile, DoublesConfig.class);
        assertEquals(List.of(1.0, 2.0, 3.0), config.list); // FAILS HERE
    }

In test 2, ConfigLib correctly converts a double without a decimal point 10 to 10.0 to store in a primitive double field. This is the behavior I expect.

In test 3, the test fails in the load method:

Can not set java.lang.Double field de.exlll.configlib.YamlConfigurationsTest$DoublesConfig.boxed to java.lang.Long
java.lang.IllegalArgumentException: Can not set java.lang.Double field de.exlll.configlib.YamlConfigurationsTest$DoublesConfig.boxed to java.lang.Long

In test 4, the load method succeeds. However, the objects in the returned List are not all Doubles:

Expected :[1.0, 2.0, 3.0]
Actual   :[1.0, 2, 3.0]
<Click to see difference>

org.opentest4j.AssertionFailedError: expected: <[1.0, 2.0, 3.0]> but was: <[1.0, 2, 3.0]>

Expected behavior
Ideally, all of these cases would be handled like the primitive double, converting an integer type to a double when the receiving Configuration type calls for it. The case with the List was how I found this, and it was the most surprising since the exception is deferred until trying to unbox the double.

Screenshots
N/A

Additional context
I found this while using the update function, not directly read/load. After calling update, the contents of the yaml file are modified to contain a decimal point (e.g. - 2 becomes - 2.0). I think serialization is handling this correctly, but not deserialization.

Something similar may happen with other polymorphic types, but this is the simplest example.

[Exlll]

Damn, thanks for catching this and for the detailed report. 🙏

[Exlll]

I've released version v4.6.4 that fixes this. Thanks again for report. :)

[joshuaprince]

Thank you for the lightning fast fix, you're awesome!