Models in Model-driven Engineering are primary development artifacts that are heavily edited in all stages of software development and that can become temporarily inconsistent during editing. In general, there are many alternatives to resolve an inconsistency, and which one is the most suitable depends on a variety of factors. As also proposed by recent approaches to model repair, it is reasonable to leave the actual choice and approval of a repair alternative to the discretion of the developer. Model repair tools can support developers by proposing a list of the most promising repairs. Such repair recommendations will be only accepted in practice if the generated proposals are plausible and understandable, and if the set as a whole is manageable. Current approaches, which mostly focus on exhaustive search strategies, exploring all possible model repairs without considering the intention of historic changes, fail in meeting these requirements. In this article, we present a new approach to generate repair proposals that aims at inconsistencies that have been introduced by past incomplete edit steps that can be located in the version history of a model. Such an incomplete edit step is either undone or it is extended to a full execution of a consistency-preserving edit operation. The history-based analysis of inconsistencies as well as the generation of repair recommendations are fully automated, and all interactive selection steps are supported by our repair tool called R E V ISION . We evaluate our approach using histories of real-world models obtained from popular open-source modeling projects hosted in the Eclipse Git repository, including the evolution of the entire UML meta-model. Our experimental results confirm our hypothesis that most of the inconsistencies, namely, 93.4, can be resolved by complementing incomplete edits. 92.6% of the generated repair proposals are relevant in the sense that their effect can be observed in the models’ histories. 94.9% of the relevant repair proposals are ranked at the topmost position.

Program slicing is a technique which can determine the simplest program possible that maintains the meaning of the original program w.r.t. a slicing criterion. The concept of slicing has been transferred to models, in particular to statecharts. In addition to the classical use cases of slicing adopted from the field of program understanding, model slicing is also motivated by specifying submodels of interest to be further processed more efficiently, thus dealing with scalability issues when working with very large models. Slices are often updated throughout specific software development tasks. Such a slice update can be performed by creating the new slice from scratch or by incrementally updating the existing slice. In this paper, we present a formal framework for defining model slicers that support incremental slice updates. This framework abstracts from the behavior of concrete slicers as well as from the concrete model modification approach. It forms a guideline for defining incremental model slicers independent of the underlying slicer’s semantics. Incremental slice updates are shown to be equivalent to non-incremental ones. Furthermore, we present a framework instantiation based on the concept of edit scripts defining application sequences of model transformation rules. We implemented two concrete model slicers for this instantiation based on the Eclipse Modeling Framework.

Model slicers are tools which provide two services: (a) finding parts of interest in a model and (b) displaying these parts somehow or extract these parts as a new, autonomous model, which is referred to as slice or sub-model. This paper focuses on the creation of editable slices, which can be processed by model editors, analysis tools, model management tools etc. Slices are useful if, e.g., only a part of a large model shall be analyzed, compared or processed by time-consuming algorithms, or if sub-models shall be modified independently. We present a new generic incremental slicer which can slice models of arbitrary type and which creates slices which are consistent in the sense that they are editable by standard editors. It is built on top of a model differencing framework and does not require additional configuration data beyond those available in the differencing framework. The slicer can incrementally extend or reduce an existing slice if model elements shall be added or removed, even if the slice has been edited meanwhile. We demonstrate the usefulness of our slicer in several scenarios using a large UML model. A screencast of the demonstrated scenarios is provided at http://pi.informatik.uni-siegen.de/projects/SiLift/ase2017.

Model-based development has become a widely-used approach to implement software, e.g. for embedded systems. Models replace source code as primary executable artifacts in these cases. Software product line technologies for these domains must be able to generate models as instances of an SPL. This need is addressed among others by an implementation technology for SPLs known as delta modeling. Current approaches to delta modeling require deltas to be written manually using delta languages, and they offer only very limited support for creating and testing a network of deltas. This paper presents a new approach to delta modeling and a supporting tool suite: the abstract notion of a delta is refined to be a consistency-preserving edit script which is generated by comparing two models. The rich structure of edit scripts allows us to detect conflicts and further relations between deltas statically and to implement restructurings in delta sets such as the merging of two deltas. We illustrate the tooling using a case study.