Core API: ChildTopics manipulators doesn't work for "many" childs

[jri]

When one of the manipulator methods is called on a ChildTopics object when the child is defined as many an exception is thrown, basically:

java.lang.RuntimeException: Invalid access to ChildTopicsModel entry "dm4.test.child": the caller assumes it to be multiple-value but it is single-value in {...}

These ChildTopics methods are affected:

set()
setRef()
remove()

Note: the Webclient handles models which include many relationships properly. Affected are 3rd-party applications (and/or migrations) which operate on a ChildTopics object directly. As a workaround create a ChildTopicsModel yourself and call the object's generic update() method.

[Jörg Richter <jri@…>]

In ca317c3d2b1fce76c097447d9d99da9c3c14eadd/deepamehta:

Add test to demonstrate issue #788.

See #788.

[Jörg Richter <jri@…>]

In 39f02dec76cce65bce6f32d7b41b0b1da28db4ac/deepamehta:

Core: add ChildTopics? "many" manipulators (#788).

CHANGES

Core API:

The ChildTopics interface has new methods to manipulate child topics which have an underlying "many" relationship:

add()
addRef()
addDeletionRef()

Note: for "one" relationships the corresponding methods are:

set()
setRef()
setDeletionRef()

IMPORTANT: to manipulate "one" or "many" child topics you must use the set and add methods repectively. When you try e.g. to manipulate child topics which have an underlying "many" relationship with the set methods, an exception is thrown.

For the first time you can manipulate "many" child topics directly via the ChildTopics object.

BREAKING CHANGES

1 method renamed in ChildTopics:

remove() -> setDeletionRef()

See #788.