Section: New Results

Tools for understanding evolution

Automatic Detection of System-Specific Conventions. In Apache Ant, a convention to improve maintenance was introduced in 2004 stating a new way to close files instead of the Java generic InputStream.close(). Yet, six years after its introduction, this convention was still not generally known to the developers. Two existing solutions could help in these cases. First, one can deprecate entities, but, in our example, one can hardly deprecate Java's method. Second, one can create a system-specific rule to be automatically enforced. In a preceding publication , we showed that system-specific rules are more likely to be noticed by developers than generic ones. However, in practice, developers rarely create specific rules. We therefore propose to free the developers from the need to create rules by automatically detecting such conventions from source code repositories. This is done by mining the change history of the system to discover similar changes being applied over several revisions. The proposed approach is applied to real-world systems, and the extracted rules are validated with the help of experts. The results show that many rules are in fact relevant for the experts. [16]

DeltaImpactFinder. In software development, version control systems (VCS) provide branching and merging support tools. Such tools are popular among developers to concurrently change a code-base in separate lines and reconcile their changes automatically afterwards. However, two changes that are correct independently can introduce bugs when merged together. We call semantic merge conflicts this kind of bugs. Change impact analysis (CIA) aims at estimating the effects of a change in a codebase. We propose to detect semantic merge conflicts using CIA. On a merge, DELTAIMPACTFINDER analyzes and compares the impact of a change in its origin and destination branches. We call the difference between these two impacts the delta-impact. If the delta-impact is empty, then there is no indicator of a semantic merge conflict and the merge can continue automatically. Otherwise, the delta-impact contains what are the sources of possible conflicts. [26]

OrionPlanning. Many techniques have been proposed in the literature to support architecture definition, conformance, and analysis. However, there is a lack of adoption of such techniques by the industry. Previous work have analyzed this poor support. Specifically, former approaches lack proper analysis techniques (e.g., detection of architectural inconsistencies), and they do not provide extension and addition of new features. We present ORIONPLANNING, a prototype tool to assist refactorings at large scale. The tool provides support for model-based refactoring operations. These operations are performed in an interactive visualization. The contributions of the tool consist in: (i) providing iterative modifications in the architecture, and (ii) providing an environment for architecture inspection and definition of dependency rules. [37]

Recording and Replaying System-Specific Conventions. During its lifetime, a software system is under continuous maintenance to remain useful. Maintenance can be achieved in activities such as adding new features, fixing bugs, improving the system’s structure, or adapting to new APIs. In such cases, developers sometimes perform sequences of code changes in a systematic way. These sequences consist of small code changes (e.g., create a class, then extract a method to this class), which are applied to groups of related code entities (e.g., some of the methods of a class). MacroRecorder is a proof-of-concept tool that records a sequence of code changes, then it allows the developer to generalize this sequence in order to apply it in other code locations. The evaluation is based on previous work on repetitive code changes related to rearchitecting. MacroRecorder was able to replay 92% of the examples, which consisted in up to seven code entities modified up to 66 times. The generation of a customizable, large-scale transformation operator has the potential to efficiently assist code maintenance. [39] , [38]