Legacy Issue Number: 16600
Source: IBM ( Mattias Mohlin)
Assume we have an object typed by a class C which inherits another class D. If an object of C is destroyed by calling an explicit destructor, and this destructor does not contain any call to a super destructor of D, what will then happen? Will the object be destroyed without calling any destructor in the super class? This would seem error-prone. We need a clarification whether this is allowed or not, and if it is allowed how the super-class part of the object will be destroyed.
Reported: ALF 1.0b1 — Fri, 14 Oct 2011 04:00 GMT
Disposition: Closed; No Change — ALF 1.1
Close, with explanation
In 10.5.3.2, it clearly states
When an object is destroyed using an explicit destructor, the default destructor behavior is not performed, so any desired calls to superclass or composite part destructors must be made explicitly.
There is no requirement that any superclass or composite part destructor calls actually be made, however – to do so is a modeler responsibility. The intent is that an explicit destructor overrides the default behavior, and it is up to the modeler to decide what the replacement behavior should be, which includes whether or not to call any other destructors. This is similar to the freedom allowed in a constructor on whether or not to call superclass constructors.
Whether or not an explicit destructor makes calls to any relevant superclass or composite part desctructors, a destructor call on an object always results in the entire object being destroyed. That is because, as stated in 8.3.10, the actual destruction of the object happens "after the completion of the call to the destructor", regardless of what the destructor does or does not do. And this destruction happens using a destroy object action with isDestroyOwnedObjects=true (see 17.10), so composite parts are also always destroyed, whether or not destructors have been called on them.
Updated: Thu, 22 Jun 2017 16:40 GMT
ALF11 — Is it allowed to omit super destructor calls in an explicit destructor?
- Key: ALF11-17
- OMG Task Force: Action Language for fUML 1.1 (ALF) RTF