ST6RI-939 Fix StackOverflow when loading a ResourceSet

[AxelRICHARD]

Fix a StackOverflow when loading a ResourceSet containing TransitionUsage elements.

Context

Loading a SysML-XMI ResourceSet can trigger a StackOverflowError when derived properties are evaluated on TransitionUsage elements.

The recursion involves the derived transition properties and the implicit member computation performed by TransitionUsageAdapter, especially around:

• TransitionUsage::source
• TransitionUsage::sourceFeature()
• TransitionUsage::succession
• implicit transition members and binding connectors

Observed Behavior

The application fails with a recursive stack similar to:

java.lang.StackOverflowError
  at org.omg.sysml.delegate.setting.TransitionUsage_source_SettingDelegate.basicGet(...)
  at org.omg.sysml.lang.sysml.impl.TransitionUsageImpl.getSource(...)
  at org.omg.sysml.adapter.TransitionUsageAdapter.computeTransitionLinkConnectors(...)
  at org.omg.sysml.adapter.TransitionUsageAdapter.addAdditionalMembers(...)
  at org.omg.sysml.util.NamespaceUtil.addAdditionalMembersTo(...)
  at org.omg.sysml.util.UsageUtil.getSourceFeatureOf(...)
  at org.omg.sysml.lang.sysml.impl.TransitionUsageImpl.sourceFeature(...)
  at org.omg.sysml.delegate.setting.TransitionUsage_source_SettingDelegate.basicGet(...)
  ...

SysML-Level Explanation

In SysML, TransitionUsage::source is a derived property. It is computed from sourceFeature(), which identifies the feature used as the source of the transition succession.

At the same time, TransitionUsageAdapter may add implicit members required by transition semantics, such as:

• the implicit source member;
• transition link connectors;
• binding connectors between the succession, the transition link, and parameters.

The issue is that this implicit member computation is not reentrant-safe.

Recursion Cycle

The problematic cycle is:

1. Code reads transition.getSource().
2. This evaluates the derived property TransitionUsage::source.
3. The derived property calls transition.sourceFeature().
4. sourceFeature() delegates to UsageUtil.getSourceFeatureOf(transition).
5. UsageUtil.getSourceFeatureOf(...) calls NamespaceUtil.addAdditionalMembersTo(transition).
6. TransitionUsageAdapter.addAdditionalMembers() calls computeTransitionLinkConnectors().
7. computeTransitionLinkConnectors() reads transition.getSource().
8. The same cycle starts again.

This leads to unbounded recursion and eventually a StackOverflowError.

Typical Trigger

The issue can occur when a TransitionUsage has parameters, but its succession-related implicit members are not fully available at the time source is evaluated.

In that state, computeTransitionLinkConnectors() attempts to compute source-related binding connectors and reads transition.getSource(), which re-enters the same implicit member computation.

Expected Behavior

Evaluating derived properties of TransitionUsage should be stable and reentrant-safe.

Reading TransitionUsage::source should not cause unbounded recursion, even if implicit transition members are still being computed.

Actual Behavior

Reading TransitionUsage::source can recursively trigger transition implicit member computation, which reads source again and causes a StackOverflowError.

[AxelRICHARD]

Hello @seidewitz do you need something else for this pull request? If no, can I set it as "Ready for review"?