Circular EGL imports cause unexpected runtime behaviour

[kolovos]

As shown in this test circular imports of EGL templates (circular1.egl imports circular2.egl which in turn imports circular1.egl again) cause unexpected behaviour at runtime. In particular, when circular1.egl is executed, it appears to lose access to the models the module is configured to run against.

[agarciadom]

I tried debugging a bit around this issue. My understanding is that the way that imports are currently given the context of the importing module is this bit of code at the end of EolModule::build:

epsilon/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/EolModule.java

Lines 176 to 180 in c5a1847

	for (Import import_ : imports) {
	import_.setContext(context);
	if (import_.isLoaded() && import_.getModule() instanceof IEolModule) {
	operations.addAll(((IEolModule)import_.getModule()).getOperations());
	}

My debugging shows that this specific line is problematic:

epsilon/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/EolModule.java

Line 177 in c5a1847

import_.setContext(context);

The problem happens as follows:

• circular1.egl parsing is attempted.
• The import of circular2.egl is found - we try to parse it.
• While parsing circular2.egl, we find the circular1.egl import - we resolve it to the same circular1.egl module as above.
• circular2.egl's EolModule::build() call overwrites circular1.egl's context, so now circular1.egl's context doesn't match that of its EglTemplateFactory.

This means that this line in the test has no effect on circular1.egl's context anymore:

module.getContext().getModelRepository().addModel(model);

That means that circular1.egl is still running with no models in it.

I think the problem is that instead of having build() clobber the context of any imported modules after parsing (which breaks in the presence of circular imports), we should have the context propagate across the import before we start parsing the imported module.

I'll submit a PR with a tentative fix based on this.

[agarciadom]

@kolovos please review #204 and merge if you're happy with the fix :-).

[agarciadom]

Fixed by #204.