FailoverIntrospector produces different results

[esfomeado]

Describe the bug

When using a FailoverIntrospector the generation fails when generating a record.

This fails:

FixtureMonkey.builder()
                .useExpressionStrictMode()
                .objectIntrospector(new FailoverIntrospector(List.of(FieldReflectionArbitraryIntrospector.INSTANCE), true))
                .pushAssignableTypeArbitraryIntrospector(Record.class, ConstructorPropertiesArbitraryIntrospector.INSTANCE)
               .build();

This works (The only difference is the FailoverIntrospector):

FixtureMonkey.builder()
                .useExpressionStrictMode()
                .objectIntrospector(FieldReflectionArbitraryIntrospector.INSTANCE)
                .pushAssignableTypeArbitraryIntrospector(Record.class, ConstructorPropertiesArbitraryIntrospector.INSTANCE)
               .build();

Your environment

• Fixture Monkey 1.1.6
• Java 21

Steps to reproduce

I´m unable to replicate this issue standalone. Here works fine but it fails in my production code.

https://github.com/esfomeado/fixture-monkey-bug/blob/master/src/test/java/com/example/bug/FixtureMonkeyTest.java#L157

Most likely something else is conflicting with this.

Expected behaviour

Should generate the value just fine

Actual behaviour

It fails to generate, no error but all fields are null

[esfomeado]

@seongahjo I was able to replicate the bug:

https://github.com/esfomeado/fixture-monkey-bug/blob/master/src/test/java/com/example/bug/FixtureMonkeyTest.java#L172

[seongahjo]

@esfomeado

Thank you for providing a reproducible example.

The result of FailoverIntrospector is intended.
When using the FailoverIntrospector, you must specify the PropertyGenerator while FieldReflectionArbitraryIntrospector provides the default PropertyGenerator.

You switch the FieldReflectionArbitraryIntrospector to FailoverIntrospector, so the properties generated by FieldReflectionArbitraryIntrospector are gone.

However, there is a bug when generating a record instance with two constructors. Let you know when it is fixed.

Thank you.

[esfomeado]

• I have specified .pushAssignableTypeArbitraryIntrospector(Record.class, ConstructorPropertiesArbitraryIntrospector.INSTANCE), so I would expect all Records to be generated using this generator and not via the FailoverIntrospector. If I remove that FailoverIntrospector that is how it behaves but when I add it the behavior changes.

• Seems wrong having to specify a PropertyGenerator. Each Introspector was their own way of generating properties and the FailoverIntrospector should let the Introspector use their own.

• Otherwise what´s the point of using the FailoverIntrospector? From my point of view the FailoverIntrospector should just call each Introspector until one was able to generate the value.

[seongahjo]

I have specified .pushAssignableTypeArbitraryIntrospector(Record.class, ConstructorPropertiesArbitraryIntrospector.INSTANCE), so I would expect all Records to be generated using this generator and not via the FailoverIntrospector

Yes, it is. The ConstructorPropertiesArbitraryIntrospector generates the properties that needed to generate Record, but due to the bug, it generates the properties of the no-args constructor, not the canonical constructor. The bug will be fixed in 1.1.9.

Otherwise what´s the point of using the FailoverIntrospector? From my point of view the FailoverIntrospector should just call each Introspector until one was able to generate the value.

I'm thinking of improving FailoverIntrospector to provide the property generation and not cause performance degradation. Please wait for it. I'll let you know when it is ready!

Thank you.