Continuous Integration and Delivery (CI/CD) practices have shown several benefits for software development and operations, such as faster release cycles and early discovery of defects. For Cyber-Physical System (CPS) development, CI/CD can help achieving required goals, such as high dependability, yet it may be challenging to apply. This article empirically investigates challenges, barriers, and their mitigation occurring when applying CI/CD practices to develop CPSs in 10 organizations working in eight different domains. The study has been conducted through semi-structured interviews, by applying an open card sorting procedure together with a member-checking survey within the same organizations, and by validating the results through a further survey involving 55 professional developers. The study reveals several peculiarities in the application of CI/CD to CPSs. These include the need for (i) combining continuous and periodic builds while balancing the use of Hardware-in-the-Loop and simulators, (ii) coping with difficulties in software deployment (iii) accounting for simulators and Hardware-in-the-Loop differing in their behavior, and (vi) combining hardware/software expertise in the development team. Our findings open the road toward recommenders aimed at supporting the setting and evolution of CI/CD pipelines, as well as university curricula requiring interdisciplinarity, such as knowledge about hardware, software, and their interplay.

Continuous Integration (CI) and Continuous Delivery (CD) are widespread in both industrial and open-source software (OSS) projects. Recent research characterized build failures in CI and identified factors potentially correlated to them. However, most observations and findings of previous work are exclusively based on OSS projects or data from a single industrial organization. This paper provides a first attempt to compare the CI processes and occurrences of build failures in 349 Java OSS projects and 418 projects from a financial organization, ING Nederland. Through the analysis of 34,182 failing builds (26% of the total number of observed builds), we derived a taxonomy of failures that affect the observed CI processes. Using cluster analysis, we observed that in some cases OSS and ING projects share similar build failure patterns (e.g., few compilation failures as compared to frequent testing failures), while in other cases completely different patterns emerge. In short, we explain how OSS and ING CI processes exhibit commonalities, yet are substantially different in their design and in the failures they report.

Continuous Delivery is an agile software develop- ment practice in which developers frequently integrate changes into the main development line and produce releases of their software. An automated Continuous Integration infrastructure builds and tests these changes. Claimed advantages of CD include early discovery of (integration) errors, reduced cycle time, and better adoption of coding standards and guidelines. This paper reports on a study in which we surveyed 152 developers of a large financial organization (ING Netherlands), and investigated how they adopt a Continuous Integration and delivery pipeline during their development activities. In our study, we focus on topics related to managing technical debt, as well as test automation practices. The survey results shed light on the adoption of some agile methods in practice, and sometimes confirm, while in other cases, confute common wisdom and results obtained in other studies. For example, we found that refactoring tends to be performed together with other development activities, technical debt is almost always “self-admitted”, developers timely document source code, and assure the quality of their product through extensive automated testing, with a third of respondents dedicating more than 50% of their time to do testing activities.