Complete problem description for Model Versioning and collaborative work

[jastram]

Stakeholders:

• Uwe Steinke

The underlying problem:

• Prevent concurrent editing
• Prevent inconsistent model states
• Prevent corrupt models
• Prevent merge operations in the first place

Possible Solutions:

• Model Store (CDO or EMFStore)
• File-based version system with locking (e.g. Subversion)
• Improve merging (e.g. EMF Compare)
• Break down the models in as many files as possible

[astante]

Just looking a bit around, there could also be http://wiki.eclipse.org/EMF_DiffMerge as an option for the merging category. The presentation http://wiki.eclipse.org/images/f/fc/EDM_KeplerDemoCamp_Frankfurt_2013.pdf mentions also UML/SysML support. There is also another presentation at http://wiki.eclipse.org/images/4/4c/EDM_ECE12.pdf .

[cecilebraun]

@MatthieuPERIN add this comment #256 (comment):

Two matters here, teh integration and also the usage that we want to had with such technologies:

    EMF Compare & Papyrus: good,On going business (OK for UML models, on going works for diagrams)
    EMF Store: not well known here
    CDO: full integration (see http://www.damus.ca/blog) but a server is needed.

[UweSteinkeFromSiemens]

As long as the corruption-free merge of model (versions) cannot be assured otherwise (by CDO or EMF or ...) the need of merging must be avoided, while different persons are able to work on a larger model in parallel.

This requires

• the ability to split larger models into separate submodels and files
• a model and file structuring method for splitting modes,
• that each of the submodels can be modified by one person exclusively at the same time
• a second person is prevented from modification
• the repeated integration of separate submodels into a larger model must be supported so that submodel modifications do not lead to inconsistent aggregate models
• sharing interface definitions and data types (from the data dictionary, ...)
• linking requirements to submodel and aggregate model artefacts

In sum, the tool chain must support the collaboration of modellers without comprising overall model, requirements tracing and data dictionary consistency.

[cecilebraun]

Form 27.02.14 Telco: how to handle the req-IF file ?

[astante]

As an "hotfix" to prevent accidential merge of files which are probably corrupted during a merge (reqif, uml), I propose to disable the merge in git via a .gitattributes file.

Filed as #329