Allow multi-level immutable references

When immutable objects are created with as following:

public class Foo {
  public Foo() {}
  public Foo(String str) {  }
}

public class Bar {
  public Bar(){ }

  public Bar(Foo foo){ }
}

public class Baz {
  public Baz() {  }

  public Baz(Bar bar) {  }
}

foo:
  - &foo !!model.Foo  ["foo"]
bar:
  - &bar !!model.Bar [*foo]
baz:
  - &baz !!model.Baz [*bar]

The library produces the following error:

Caused by: org.yaml.snakeyaml.error.YAMLException: Immutable objects cannot be recursive.
        at org.yaml.snakeyaml.constructor.Constructor$ConstructSequence.construct2ndStep(Constructor.java:653)

Reader position:

in 'reader', line 4, column 5:
      - &bar !!model.Bar [*foo]

In other words, since all the objects are immutable and I reference *bar for creating &baz, I receive this error.

As a hack to this, I do the following.

public class Foo {
  public Foo() {}
  public Foo(String str) {  }
}

public class Bar {
  private Foo foo;
  public Bar(){ }

  public Bar(Foo[] foo){ this.foo = foo[0]; }
}

public class Baz {
  public Baz() {  }

  public Baz(Bar bar) {  }
}

And convert the first reference to a sequence

foo:
  - &foo !!model.Foo  ["foo"]
bar:
  - &bar !!model.Bar [[*foo]]
baz:
  - &baz !!model.Baz [*bar]

and it works.

However, I believe it should allow the normal case without having to refer to objects in arrays/sequences

(I use snakeyaml 1.7)

Comments (8)