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Improper Input Validation (IIV) is a software vulnerability that occurs when a system does not safely handle input data. Even though IIV is easy to detect and fix, it still commonly happens in practice. In this paper, we study to what extent developers can detect IIV and investigate underlying reasons. This knowledge is essential to better understand how to support developers in creating secure software systems. We conduct an online experiment with 146 participants, of which 105 report at least three years of professional software development experience. Our results show that the existence of a visible attack scenario facilitates the detection of IIV vulnerabilities and that a significant portion of developers who did not find the vulnerability initially could identify it when warned about its existence. Yet, a total of 60 participants could not detect the vulnerability even after the warning. Other factors, such as the frequency with which the participants perform code reviews, influence the detection of IIV. [ABSTRACT FROM AUTHOR]

This paper explores the question: when faced with a fixed time-constraint, what impact does a process have on developers’ abilities to create effective educational games? In this paper, we discuss the process in which educational games are constructed and explore how different processes related to software development could impact those games, both from a product and process standpoint. The paper highlights how one of the authors used two different processes related to developing games, a design-based process versus a scrum framework with students in a course where they focused on developing educational games. With presenting data on evaluations of the products produced and surveys of the student experience, the paper aims to highlight how the process may have influenced both the products that were constructed and the experience for the students in the class. [ABSTRACT FROM AUTHOR]

This paper describes the results of a large (+1100 responses) survey of professional software developers concerning standards for naming source code methods. The various standards for source code method names are derived from and supported in the software engineering literature. The goal of the survey is to determine if there is a general consensus among developers that the standards are accepted and used in practice. Additionally, the paper examines factors such as years of experience and programming language knowledge in the context of survey responses. The survey results show that participants very much agree about the importance of various standards and how they apply to names and that years of experience and the programming language has almost no effect on their responses. The results imply that the given standards are both valid and to a large degree complete. The work provides a foundation for automated method name assessment during development and code reviews. [ABSTRACT FROM AUTHOR]

This paper deals with the special type of syntax highlighting which is powered by combination of DEMO methodology (Design & Engineering Methodology for Organizations), BDD technique (Behaviour-Driven Development). Main contribution of this paper is the idea how to highlight business relevant code in IDEs (Integrated Development Environments) and notice a developer about the fact that important part of code base is edited. The proposal of the implementation encounters usage of code coverage technique and user stories derived upon DEMO methodology. [ABSTRACT FROM AUTHOR]

Links are an essential feature of the World Wide Web, and source code repositories are no exception. However, despite their many undisputed benefits, links can suffer from decay, insufficient versioning, and lack of bidirectional traceability. In this paper, we investigate the role of links contained in source code comments from these perspectives. We conducted a large-scale study of around 9.6 million links to establish their prevalence, and we used a mixed-methods approach to identify the links' targets, purposes, decay, and evolutionary aspects. We found that links are prevalent in source code repositories, that licenses, software homepages, and specifications are common types of link targets, and that links are often included to provide metadata or attribution. Links are rarely updated, but many link targets evolve. Almost 10% of the links included in source code comments are dead. We then submitted a batch of link-fixing pull requests to open source software repositories, resulting in most of our fixes being merged successfully. Our findings indicate that links in source code comments can indeed be fragile, and our work opens up avenues for future work to address these problems. [ABSTRACT FROM AUTHOR]

Practitioners use infrastructure as code (IaC) scripts to provision servers and development environments. While developing IaC scripts, practitioners may inadvertently introduce security smells. Security smells are recurring coding patterns that are indicative of security weakness and can potentially lead to security breaches. The goal of this paper is to help practitioners avoid insecure coding practices while developing infrastructure as code (IaC) scripts through an empirical study of security smells in IaC scripts. We apply qualitative analysis on 1,726 IaC scripts to identify seven security smells. Next, we implement and validate a static analysis tool called Security Linter for Infrastructure as Code scripts (SLIC) to identify the occurrence of each smell in 15,232 IaC scripts collected from 293 open source repositories. We identify 21,201 occurrences of security smells that include 1,326 occurrences of hard-coded passwords. We submitted bug reports for 1,000 randomly-selected security smell occurrences.We obtain 212 responses to these bug reports, of which 148 occurrences were accepted by the development teams to be fixed. We observe security smells can have a long lifetime, e.g., a hard-coded secret can persist for as long as 98 months, with a median lifetime of 20 months. [ABSTRACT FROM AUTHOR]

We have been generally successful for transferring software engineering knowledge to industry through various forms of education. However, many challenges in software engineering training remain. A key amongst these is how best to energise software engineering education with real-world software engineering practices. This paper describes our experience of delivering a radically different approach based on the notion of a Software Design Studio. The Software Design Studio is both a lab for students engaged in conceiving, designing and developing software products as well as an approach for teaching software engineering in the lab which emphasizes practical hands-on work and experimentation. The feedback on the Software Design Studio -- from both staff and students -- has been outstanding. Although the programme is designed as a small, elite programme there is interest to see if the teaching methods can be transferred across to the much larger undergraduate programme in Computer Science. In this paper, we provide a detailed description of how our studio works in practice so that others, thinking of taking a studio or studio-inspired approach, can use in designing their own courses. [ABSTRACT FROM AUTHOR]

The tools and infrastructure used in tech, including Open Source Software (OSS), can embed "inclusivity bugs"-- features that disproportionately disadvantage particular groups of contributors. To see whether OSS developers have existing practices to ward off such bugs, we surveyed 266 OSS developers. Our results show that a majority (77%) of developers do not use any inclusivity practices, and 92% of respondents cited a lack of concrete resources to enable them to do so. To help fill this gap, this paper introduces AID, a tool that automates the GenderMag method to systematically find gender-inclusivity bugs in software. We then present the results of the tool's evaluation on 20 GitHub projects. The tool achieved precision of 0.69, recall of 0.92, an F-measure of 0.79 and even captured some inclusivity bugs that human GenderMag teams missed. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Vehicles (UAVs) are an emerging computation platform known for their safety-critical need. In this paper, we conduct an empirical study on a widely used open-source UAV software framework, Paparazzi, with the goal of understanding the safety-critical concerns of UAV software from a bottom-up developer-in-the-field perspective. We set our focus on the use of Bounding Functions (BFs), the runtime checks injected by Paparazzi developers on the range of variables. Through an in-depth analysis on BFs in the Paparazzi autopilot software, we found a large number of them (109 instances) are used to bound safety-critical variables essential to the cyber-physical nature of the UAV, such as its thrust, its speed, and its sensor values. The novel contributions of this study are two fold. First, we take a static approach to classify all BF instances, presenting a novel datatype-based 5-category taxonomy with fine-grained insight on the role of BFs in ensuring the safety of UAV systems. Second, we dynamically evaluate the impact of the BF uses through a differential approach, establishing the UAV behavioral difference with and without BFs. The two-pronged static and dynamic approach together illuminates a rarely studied design space of safety-critical UAV software systems. [ABSTRACT FROM AUTHOR]

Regulations, standards, and guidelines for safety-critical systems stipulate stringent traceability but do not prescribe the corresponding, detailed software engineering process. Given the industrial practice of using only semi-formal notations to describe engineering processes, processes are rarely "executable" and developers have to spend significant manual effort in ensuring that they follow the steps mandated by quality assurance. The size and complexity of systems and regulations makes manual, timely feedback from Quality Assurance (QA) engineers infeasible. In this paper we propose a novel framework for tracking processes in the background, automatically checking QA constraints depending on process progress, and informing the developer of unfulfilled QA constraints. We evaluate our approach by applying it to two different case studies; one open source community system and a safety-critical system in the air-traffic control domain. Results from the analysis show that trace links are often corrected or completed after the fact and thus timely and automated constraint checking support has significant potential on reducing rework. [ABSTRACT FROM AUTHOR]

Generate-and-validate (G&V) automated program repair (APR) techniques have been extensively studied during the past decade. Meanwhile, such techniques can be extremely time-consuming due to the manipulation of program code to fabricate a large number of patches and also the repeated test executions on patches to identify potential fixes. PraPR, a recent G&V APR technique, reduces such costs by modifying program code directly at the level of compiled JVM bytecode with on-the-fly patch validation, which directly allows multiple bytecode patches to be tested within the same JVM process. However, PraPR is limited due to its unique bytecode-repair design, and is basically unsound/imprecise as it assumes that patch executions do not change global JVM state and affect later patch executions on the same JVM process. In this paper, we propose a unified patch validation framework, named UniAPR, to perform the first empirical study of on-the-fly patch validation for state-of-the-art source-code-level APR techniques widely studied in the literature; furthermore, UniAPR addresses the imprecise patch validation issue by resetting the JVM global state via runtime bytecode transformation. We have implemented UniAPR as a publicly available fully automated Maven Plugin. Our study demonstrates for the first time that on-the-fly patch validation can often speed up state-of-the-art source-code-level APR by over an order of magnitude, enabling all existing APR techniques to explore a larger search space to fix more bugs in the near future. Furthermore, our study shows the first empirical evidence that vanilla on-the-fly patch validation can be imprecise/unsound, while UniAPR with JVM reset is able to mitigate such issues with negligible overhead. [ABSTRACT FROM AUTHOR]

When a bug manifests in a user-facing application, it is likely to be exposed through the graphical user interface (GUI). Given the importance of visual information to the process of identifying and understanding such bugs, users are increasingly making use of screenshots and screen-recordings as a means to report issues to developers. However, when such information is reported en masse, such as during crowd-sourced testing, managing these artifacts can be a time-consuming process. As the reporting of screen-recordings in particular becomes more popular, developers are likely to face challenges related to manually identifying videos that depict duplicate bugs. Due to their graphical nature, screen-recordings present challenges for automated analysis that preclude the use of current duplicate bug report detection techniques. To overcome these challenges and aid developers in this task, this paper presents TANGO, a duplicate detection technique that operates purely on video-based bug reports by leveraging both visual and textual information. TANGO combines tailored computer vision techniques, optical character recognition, and text retrieval. We evaluated multiple configurations of TANGO in a comprehensive empirical evaluation on 4,860 duplicate detection tasks that involved a total of 180 screen-recordings from six Android apps. Additionally, we conducted a user study investigating the effort required for developers to manually detect duplicate video-based bug reports and compared this to the effort required to use TANGO. The results reveal that TANGO's optimal configuration is highly effective at detecting duplicate video-based bug reports, accurately ranking target duplicate videos in the top-2 returned results in 83% of the tasks. Additionally, our user study shows that, on average, TANGO can reduce developer effort by over 60%, illustrating its practicality. [ABSTRACT FROM AUTHOR]

Crowdsourced testing is increasingly dominant in mobile application (app) testing, but it is a great burden for app developers to inspect the incredible number of test reports. Many researches have been proposed to deal with test reports based only on texts or additionally simple image features. However, in mobile app testing, texts contained in test reports are condensed and the information is inadequate. Many screenshots are included as complements that contain much richer information beyond texts. This trend motivates us to prioritize crowdsourced test reports based on a deep screenshot understanding. In this paper, we present a novel crowdsourced test report prioritization approach, namely DEEPPRIOR. We first represent the crowdsourced test reports with a novelly introduced feature, namely DEEPFEATURE, that includes all the widgets along with their texts, coordinates, types, and even intents based on the deep analysis of the app screenshots, and the textual descriptions in the crowdsourced test reports. DEEPFEATURE includes the Bug Feature, which directly describes the bugs, and the Context Feature, which depicts the thorough context of the bug. The similarity of the DEEPFEATURE is used to represent the test reports' similarity and prioritize the crowdsourced test reports. We formally define the similarity as DEEPSIMILARITY. We also conduct an empirical experiment to evaluate the effectiveness of the proposed technique with a large dataset group. The results show that DEEPPRIOR is promising, and it outperforms the state-of-the-art approach with less than half the overhead. [ABSTRACT FROM AUTHOR]

Various proxy metrics for test quality have been defined in order to guide developers when writing tests. Code coverage is particularly well established in practice, even though the question of how coverage relates to test quality is a matter of ongoing debate. Mutation testing offers a promising alternative: Artificial defects can identify holes in a test suite, and thus provide concrete suggestions for additional tests. Despite the obvious advantages of mutation testing, it is not yet well established in practice. Until recently, mutation testing tools and techniques simply did not scale to complex systems. Although they now do scale, a remaining obstacle is lack of evidence that writing tests for mutants actually improves test quality. In this paper we aim to fill this gap: By analyzing a large dataset of almost 15 million mutants, we investigate how these mutants influenced developers over time, and how these mutants relate to real faults. Our analyses suggest that developers using mutation testing write more tests, and actively improve their test suites with high quality tests such that fewer mutants remain. By analyzing a dataset of past fixes of real high-priority faults, our analyses further provide evidence that mutants are indeed coupled with real faults. In other words, had mutation testing been used for the changes introducing the faults, it would have reported a live mutant that could have prevented the bug. [ABSTRACT FROM AUTHOR]

Software reuse, especially partial reuse, poses legal and security threats to software development. Since its source codes are usually unavailable, software reuse is hard to be detected with interpretation. On the other hand, current approaches suffer from poor detection accuracy and efficiency, far from satisfying practical demands. To tackle these problems, in this paper, we propose ISRD, an interpretation-enabled software reuse detection approach based on a multi-level birthmark model that contains function level, basic block level, and instruction level. To overcome obfuscation caused by cross-compilation, we represent function semantics with Minimum Branch Path (MBP) and perform normalization to extract core semantics of instructions. For efficiently detecting reused functions, a process for "intent search based on anchor recognition" is designed to speed up reuse detection. It uses strict instruction match and identical library call invocation check to find anchor functions (in short anchors) and then traverses neighbors of the anchors to explore potentially matched function pairs. Extensive experiments based on two real-world binary datasets reveal that ISRD is interpretable, effective, and efficient, which achieves 97:2% precision and 94:8% recall. Moreover, it is resilient to cross-compilation, outperforming state-of- the-art approaches. [ABSTRACT FROM AUTHOR]

Open-source software (OSS) is widely reused as it provides convenience and efficiency in software development. Despite evident benefits, unmanaged OSS components can introduce threats, such as vulnerability propagation and license violation. Unfortunately, however, identifying reused OSS components is a challenge as the reused OSS is predominantly modified and nested. In this paper, we propose CENTRIS, a precise and scalable approach for identifying modified OSS reuse. By segmenting an OSS code base and detecting the reuse of a unique part of the OSS only, CENTRIS is capable of precisely identifying modified OSS reuse in the presence of nested OSS components. For scalability, CENTRIS eliminates redundant code comparisons and accelerates the search using hash functions. When we applied CENTRIS on 10,241 widely-employed GitHub projects, comprising 229,326 versions and 80 billion lines of code, we observed that modified OSS reuse is a norm in software development, occurring 20 times more frequently than exact reuse. Nonetheless, CENTRIS identified reused OSS components with 91% precision and 94% recall in less than a minute per application on average, whereas a recent clone detection technique, which does not take into account modified and nested OSS reuse, hardly reached 10% precision and 40% recall. [ABSTRACT FROM AUTHOR]

Bugs that persist into releases of video games can have negative impacts on both developers and users, but particular aspects of testing in game development can lead to difficulties in effectively catching these missed bugs. It has become common practice for developers to apply updates to games in order to fix missed bugs. These updates are often accompanied by notes that describe the changes to the game included in the update. However, some bugs reappear even after an update attempts to fix them. In this paper, we develop a taxonomy for bug types in games that is based on prior work. We examine 12,122 bug fixes from 723 updates for 30 popular games on the Steam platform. We label the bug fixes included in these updates to identify the frequency of these different bug types, the rate at which bug types recur over multiple updates, and which bug types are treated as more severe. Additionally, we survey game developers regarding their experience with different bug types and what aspects of game development they most strongly associate with bug appearance. We find that Information bugs appear the most frequently in updates, while Crash bugs recur the most frequently and are often treated as more severe than other bug types. Finally, we find that challenges in testing, code quality, and bug reproduction have a close association with bug persistence. These findings should help developers identify which aspects of game development could benefit from greater attention in order to prevent bugs. Researchers can use our results in devising tools and methods to better identify and address certain bug types. [ABSTRACT FROM AUTHOR]

This paper presents a coverage-guided grammarbased fuzzing technique for automatically synthesizing a corpus of concise test inputs. We walk-through a case study of a compiler designed for education and the corresponding problem of generating meaningful test cases to provide to students. The prior state-of-the-art solution is a combination of fuzzing and test-case reduction techniques such as variants of delta-debugging. Our key insight is that instead of attempting to minimize convoluted fuzzer-generated test inputs, we can instead grow concise test inputs by construction using a form of iterative deepening. We call this approach bonsai fuzzing. Experimental results show that bonsai fuzzing can generate test corpora having inputs that are 16-45% smaller in size on average as compared to a fuzz-then-reduce approach, while achieving approximately the same code coverage and fault-detection capability. [ABSTRACT FROM AUTHOR]

Recent years have witnessed a wide array of results in software testing, exploring different approaches and methodologies ranging from fuzzers to symbolic engines, with a full spectrum of instances in between such as concolic execution and hybrid fuzzing. A key ingredient of many of these tools is Satisfiability Modulo Theories (SMT) solvers, which are used to reason over symbolic expressions collected during the analysis. In this paper, we investigate whether techniques borrowed from the fuzzing domain can be applied to check whether symbolic formulas are satisfiable in the context of concolic and hybrid fuzzing engines, providing a viable alternative to classic SMT solving techniques. We devise a new approximate solver, FUZZY-SAT, and show that it is both competitive with and complementary to state-of-the-art solvers such as Z3 with respect to handling queries generated by hybrid fuzzers. [ABSTRACT FROM AUTHOR]

Misleading method names in software projects can confuse developers, which may lead to software defects and affect code understandability. In this paper, we present DEEPNAME, a context-based, deep learning approach to detect method name inconsistencies and suggest a proper name for a method. The key departure point is the philosophy of "Show Me Your Friends, I'll Tell You Who You Are". Unlike the state-of-the-art approaches, in addition to the method's body, we also consider the interactions of the current method under study with the other ones including the caller and callee methods, and the sibling methods in the same enclosing class. The sequences of sub-tokens in the program entities' names in the contexts are extracted and used as the input for an RNN-based encoder-decoder to produce the representations for the current method. We modify that RNN model to integrate the copy mechanism and our newly developed component, called the non-copy mechanism, to emphasize on the possibility of a certain sub-token not to be copied to follow the current sub-token in the currently generated method name. We conducted several experiments to evaluate DEEPNAME on large datasets with +14M methods. For consistency checking, DEEPNAME improves the state-of-the-art approach by 2.1%, 19.6%, and 11.9% relatively in recall, precision, and F-score, respectively. For name suggestion, DEEPNAME improves relatively over the state-of-the-art approaches in precision (1.8%-30.5%), recall (8.8%-46.1%), and F-score (5.2%-38.2%). To assess DEEPNAME's usefulness, we detected inconsistent methods and suggested new method names in active projects. Among 50 pull requests, 12 were merged into the main branch. In total, in 30/50 cases, the team members agree that our suggested method names are more meaningful than the current names. [ABSTRACT FROM AUTHOR]

High-quality and large-scale repositories of real bugs and their concise patches collected from real-world applications are critical for research in the software engineering community. In such a repository, each real bug is explicitly associated with its fix. Therefore, on one side, the real bugs and their fixes may inspire novel approaches for finding, locating, and repairing software bugs; on the other side, the real bugs and their fixes are indispensable for rigorous and meaningful evaluation of approaches for software testing, fault localization, and program repair. To this end, a number of such repositories, e.g., Defects4J, have been proposed. However, such repositories are rather small because their construction involves expensive human intervention. Although bug-fixing code commits as well as associated test cases could be retrieved from version control systems automatically, existing approaches could not yet automatically extract concise bug-fixing patches from bug-fixing commits because such commits often involve bug-irrelevant changes. In this paper, we propose an automatic approach, called BugBuilder, to extracting complete and concise bug-fixing patches from human-written patches in version control systems. It excludes refactorings by detecting refactorings involved in bug-fixing commits, and reapplying detected refactorings on the faulty version. It enumerates all subsets of the remaining part and validates them on test cases. If none of the subsets has the potential to be a complete bug-fixing patch, the remaining part as a whole is taken as a complete and concise bug-fixing patch. Evaluation results on 809 real bug-fixing commits in Defects4J suggest that BugBuilder successfully generated complete and concise bug-fixing patches for forty percent of the bug-fixing commits, and its precision (99%) was even higher than human experts. [ABSTRACT FROM AUTHOR]

Virtual Reality (VR) is an emerging technique that provides immersive experience for users. Due to the high computation cost of rendering real-time animation twice (for both eyes) and the resource limitation of wearable devices, VR applications often face performance bottlenecks and performance optimization plays an important role in VR software development. Performance optimizations of VR applications can be very different from those in traditional software as VR involves more elements such as graphics rendering and real-time animation. In this paper, we present the first empirical study on 183 realworld performance optimizations from 45 VR software projects. In particular, we manually categorized the optimizations into 11 categories, and applied static analysis to identify how they affect different life-cycle phases of VR applications. Furthermore, we studied the complexity and design / behavior effects of performance optimizations, and how optimizations are different between large organizational software projects and smaller personal software projects. Our major findings include: (1) graphics simplification (24.0%), rendering optimization (16.9%), language / API optimization (15.3%), heap avoidance (14.8%), and value caching (12.0%) are the most common categories of performance optimization in VR applications; (2) game logic updates (30.4%) and before-scene initialization (20.0%) are the most common lifecycle phases affected by performance issues; (3) 45.9% of the optimizations have behavior and design effects and 39.3% of the optimizations are systematic changes; (4) the distributions of optimization classes are very different between organizational VR projects and personal VR projects. [ABSTRACT FROM AUTHOR]

During regression testing, developers rely on the pass or fail outcomes of tests to check whether changes broke existing functionality. Thus, flaky tests, which nondeterministically pass or fail on the same code, are problematic because they provide misleading signals during regression testing. Although flaky tests are the focus of several existing studies, none of them study (1) the reoccurrence, runtimes, and time-before-fix of flaky tests, and (2) flaky tests indepth on proprietary projects. This paper fills this knowledge gap about flaky tests and investigates whether prior categorization work on flaky tests also apply to proprietary projects. Specifically, we study the lifecycle of flaky tests in six large-scale proprietary projects at Microsoft.We find, as in prior work, that asynchronous calls are the leading cause of flaky tests in these Microsoft projects. Therefore, we propose the first automated solution, called Flakiness and Time Balancer (FaTB), to reduce the frequency of flaky-test failures caused by asynchronous calls. Our evaluation of five such flaky tests shows that FaTB can reduce the running times of these tests by up to 78% without empirically affecting the frequency of their flaky-test failures. Lastly, our study finds several cases where developers claim they "fixed" a flaky test but our empirical experiments show that their changes do not fix or reduce these tests' frequency of flaky-test failures. Future studies should be more cautious when basing their results on changes that developers claim to be "fixes". [ABSTRACT FROM AUTHOR]

This paper discuss about the role of Decision Support Tool in Travelling Salesman Problem (TSP) for helping the researchers who doing research in same area will get the better result from the proposed algorithm. A study has been conducted and Rapid Application Development (RAD) model has been use as a methodology which includes requirement planning, user design, construction and cutover. Water Flow Algorithm (WFA) with initialization technique improvement is used as the proposed algorithm in this study for evaluating effectiveness against TSP cases. For DST evaluation will go through usability testing conducted on system use, quality of information, quality of interface and overall satisfaction. Evaluation is needed for determine whether this tool can assists user in making a decision to solve TSP problems with the proposed algorithm or not. Some statistical result shown the ability of this tool in term of helping researchers to conduct the experiments on the WFA with improvements TSP initialization. [ABSTRACT FROM AUTHOR]

Models are an important tool in conquering the increasing complexity of modern software systems. Key industries are strategically directing their development environments towards more extensive use of modeling techniques. MiSE 2015 aimed to understand, through critical analysis, the current and future uses of models in the engineering of software-intensive systems. The MiSE workshop series has proven to be an effective forum for discussing modeling techniques from both the MDE and software engineering perspectives. An important goal of this workshop is to foster exchange between these two communities. In 2015 the focus was on considering the current state of tool support and the challenges that need to be addressed to improve the maturity of tools. There was also analysis of successful applications of modeling techniques in specific application domains, with attempts to determine how the participants' experiences can be carried over to other domains. [ABSTRACT FROM AUTHOR]

Safety Assurance Cases (SACs) are increasingly used to guide and evaluate the safety of software-intensive systems. They are used to construct a hierarchically organized set of claims, arguments, and evidence in order to provide a structured argument that a system is safe for use. However, as the system evolves and grows in size, a SAC can be difficult to maintain. In this paper we utilize design science to develop a novel solution for identifying areas of a SAC that are affected by changes to the system. Moreover, we generate actionable recommendations for updating the SAC, including its underlying artifacts and trace links, in order to evolve an existing safety case for use in a new version of the system. Our approach, Safety Artifact Forest Analysis (SAFA), leverages traceability to automatically compare software artifacts from a previously approved or certified version with a new version of the system. We identify, visualize, and explain changes in a Delta Tree. We evaluate our approach using the Dronology system for monitoring and coordinating the actions of cooperating, small Unmanned Aerial Vehicles. Results from a user study show that SAFA helped users to identify changes that potentially impacted system safety and provided information that could be used to help maintain and evolve a SAC1. [ABSTRACT FROM AUTHOR]

Test-Driven Code Review (TDR) is a code review practice in which a reviewer inspects a patch by examining the changed test code before the changed production code. Although this practice has been mentioned positively by practitioners in informal literature and interviews, there is no systematic knowledge of its effects, prevalence, problems, and advantages. In this paper, we aim at empirically understanding whether this practice has an effect on code review effectiveness and how developers' perceive TDR.We conduct (i) a controlled experiment with 93 developers that perform more than 150 reviews, and (ii) 9 semi-structured interviews and a survey with 103 respondents to gather information on how TDR is perceived. Key results from the experiment show that developers adopting TDR find the same proportion of defects in production code, but more in test code, at the expenses of fewer maintainability issues in production code. Furthermore, we found that most developers prefer to review production code as they deem it more critical and tests should follow from it. Moreover, general poor test code quality and no tool support hinder the adoption of TDR. Public preprint: [https: //doi.org/10.5281/zenodo.2551217], data and materials: [https:// doi.org/10.5281/zenodo.2553139]. [ABSTRACT FROM AUTHOR]

Software developers interact with APIs on a daily basis and, therefore, often face the need to learn how to use new APIs suitable for their purposes. Previous work has shown that recommending usage patterns to developers facilitates the learning process. Current approaches to usage pattern recommendation, however, still suffer from high redundancy and poor run-time performance. In this paper, we reformulate the problem of usage pattern recommendation in terms of a collaborative- filtering recommender system. We present a new tool, FOCUS, which mines open-source project repositories to recommend API method invocations and usage patterns by analyzing how APIs are used in projects similar to the current project. We evaluate FOCUS on a large number of Java projects extracted from GitHub and Maven Central and find that it outperforms the stateof- the-art approach PAM with regards to success rate, accuracy, and execution time. Results indicate the suitability of contextaware collaborative-filtering recommender systems to provide API usage patterns. [ABSTRACT FROM AUTHOR]

Code completion is commonly used by software developers and is integrated into all major IDE's. Good completion tools can not only save time and effort but may also help avoid incorrect API usage. Many proposed completion tools have shown promising results on synthetic benchmarks, but these benchmarks make no claims about the realism of the completions they test. This lack of grounding in real-world data could hinder our scientific understanding of developer needs and of the efficacy of completion models. This paper presents a case study on 15,000 code completions that were applied by 66 real developers, which we study and contrast with artificial completions to inform future research and tools in this area.We find that synthetic benchmarks misrepresent many aspects of real-world completions; tested completion tools were far less accurate on real-world data.Worse, on the few completions that consumed most of the developers' time, prediction accuracy was less than 20% -- an effect that is invisible in synthetic benchmarks. Our findings have ramifications for future benchmarks, tool design and real-world efficacy: Benchmarks must account for completions that developers use most, such as intra-project APIs; models should be designed to be amenable to intra-project data; and real-world developer trials are essential to quantifying performance on the least predictable completions, which are both most time-consuming and far more typical than artificial data suggests. We publicly release our preprint [https://doi.org/10.5281/zenodo.2565673] and replication data and materials [https://doi.org/10.5281/zenodo.2562249]. [ABSTRACT FROM AUTHOR]

Fuzzing is an important technique to detect software bugs and vulnerabilities. It works by mutating a small set of seed inputs to generate a large number of new inputs. Fuzzers' performance often substantially degrades when valid seed inputs are not available. Although existing techniques such as symbolic execution can generate seed inputs from scratch, they have various limitations hindering their applications in real-world complex software. In this paper, we propose a novel fuzzing technique that features the capability of generating valid seed inputs. It piggy-backs on AFL to identify input validity checks and the input fields that have impact on such checks. It further classifies these checks according to their relations to the input. Such classes include arithmetic relation, object offset, data structure length and so on. A multi-goal search algorithm is developed to apply class-specific mutations in order to satisfy inter-dependent checks all together. We evaluate our technique on 20 popular benchmark programs collected from other fuzzing projects and the Google fuzzer test suite, and compare it with existing fuzzers AFL and AFLFast, symbolic execution engines KLEE and S2E, and a hybrid tool Driller that combines fuzzing with symbolic execution. The results show that our technique is highly effective and efficient, out-performing the other tools. [ABSTRACT FROM AUTHOR]

Node.js has been widely-used as an event-driven server-side architecture. To improve performance, a task in a Node.js application is usually divided into a group of events, which are non-deterministically scheduled by Node.js. Developers may assume that the group of events (named atomic event group) should be atomically processed, without interruption. However, the atomicity of an atomic event group is not guaranteed by Node.js, and thus other events may interrupt the execution of the atomic event group, break down the atomicity and cause unexpected results. Existing approaches mainly focus on event race among two events, and cannot detect high-level atomicity violations among a group of events. In this paper, we propose NodeAV, which can predictively detect atomicity violations in Node.js applications based on an execution trace. Based on happens-before relations among events in an execution trace, we automatically identify a pair of events that should be atomically processed, and use predefined atomicity violation patterns to detect atomicity violations. We have evaluated NodeAV on real-world Node.js applications. The experimental results show that NodeAV can effectively detect atomicity violations in these Node.js applications. [ABSTRACT FROM AUTHOR]

Streaming APIs are becoming more pervasive in mainstream Object-Oriented programming languages. For example, the Stream API introduced in Java 8 allows for functional-like, MapReduce-style operations in processing both finite and infinite data structures. However, using this API efficiently involves subtle considerations like determining when it is best for stream operations to run in parallel, when running operations in parallel can be less efficient, and when it is safe to run in parallel due to possible lambda expression side-effects. In this paper, we present an automated refactoring approach that assists developers in writing efficient stream code in a semanticspreserving fashion. The approach, based on a novel data ordering and typestate analysis, consists of preconditions for automatically determining when it is safe and possibly advantageous to convert sequential streams to parallel and unorder or de-parallelize already parallel streams. The approach was implemented as a plug-in to the Eclipse IDE, uses the WALA and SAFE analysis frameworks, and was evaluated on 11 Java projects consisting of ~642K lines of code. We found that 57 of 157 candidate streams (36.31%) were refactorable, and an average speedup of 3.49 on performance tests was observed. The results indicate that the approach is useful in optimizing stream code to their full potential. [ABSTRACT FROM AUTHOR]

Over the past decades, numerous approaches were proposed to help practitioner to predict or locate defective files. These techniques often use syntactic dependency, history cochange relation, or semantic similarity. The problem is that, it remains unclear whether these different dependency relations will present similar accuracy in terms of defect prediction and localization. In this paper, we present our systematic investigation of this question from the perspective of software architecture. Considering files involved in each dependency type as an individual design space, we model such a design space using one DRSpace. We derived 3 DRSpaces for each of the 117 Apache open source projects, with 643,079 revision commits and 101,364 bug reports in total, and calculated their interactions with defective files. The experiment results are surprising: the three dependency types present significantly different architectural views, and their interactions with defective files are also drastically different. Intuitively, they play completely different roles when used for defect prediction/localization. The good news is that the combination of these structures has the potential to improve the accuracy of defect prediction/localization. In summary, our work provides a new perspective regarding to which type(s) of relations should be used for the task of defect prediction/localization. These quantitative and qualitative results also advance our knowledge of the relationship between software quality and architectural views formed using different dependency types. [ABSTRACT FROM AUTHOR]

Java is one of the most widely used programming languages. However, the absence of explicit support for architectural constructs, such as software components, in the programming language itself has prevented software developers from achieving the many benefits that come with architecturebased development. To address this issue, Java 9 has introduced the Java Platform Module System (JPMS), resulting in the first instance of encapsulation of modules with rich software architectural interfaces added to a mainstream programming language. The primary goal of JPMS is to construct and maintain large applications efficiently--as well as improve the encapsulation, security, and maintainability of Java applications in general and the JDK itself. A challenge, however, is that module declarations do not necessarily reflect actual usage of modules in an application, allowing developers to mistakenly specify inconsistent dependencies among the modules. In this paper, we formally define 8 inconsistent modular dependencies that may arise in Java-9 applications. We also present DARCY, an approach that leverages these definitions and static program analyses to automatically (1) detect the specified inconsistent dependencies within Java applications and (2) repair those identified inconsistencies. The results of our experiments, conducted over 38 open-source Java-9 applications, indicate that architectural inconsistencies are widespread and demonstrate the benefits of DARCY in automated detection and repair of these inconsistencies. [ABSTRACT FROM AUTHOR]

Maintaining awareness of useful tools is a substantial challenge for developers. Physical newsletters are a simple technique to inform developers about tools. In this paper, we evaluate such a technique, called Testing on the Toilet, by performing a mixed-methods case study. We first quantitatively evaluate how effective this technique is by applying statistical causal inference over six years of data about tools used by thousands of developers. We then qualitatively contextualize these results by interviewing and surveying 382 developers, from authors to editors to readers. We found that the technique was generally effective at increasing software development tool use, although the increase varied depending on factors such as the breadth of applicability of the tool, the extent to which the tool has reached saturation, and the memorability of the tool name. [ABSTRACT FROM AUTHOR]

Most modern Issue Tracking Systems (ITSs) for open source software (OSS) projects allow users to add comments to issues. Over time, these comments accumulate into discussion threads embedded with rich information about the software project, which can potentially satisfy the diverse needs of OSS stakeholders. However, discovering and retrieving relevant information from the discussion threads is a challenging task, especially when the discussions are lengthy and the number of issues in ITSs are vast. In this paper, we address this challenge by identifying the information types presented in OSS issue discussions. Through qualitative content analysis of 15 complex issue threads across three projects hosted on GitHub, we uncovered 16 information types and created a labeled corpus containing 4656 sentences. Our investigation of supervised, automated classification techniques indicated that, when prior knowledge about the issue is available, Random Forest can effectively detect most sentence types using conversational features such as the sentence length and its position. When classifying sentences from new issues, Logistic Regression can yield satisfactory performance using textual features for certain information types, while falling short on others. Our work represents a nontrivial first step towards tools and techniques for identifying and obtaining the rich information recorded in the ITSs to support various software engineering activities and to satisfy the diverse needs of OSS stakeholders. [ABSTRACT FROM AUTHOR]

Today, we depend on numerous large-scale services for basic operations such as email. These services, built on the basis of Continuous Integration/Continuous Deployment (CI/CD) processes, are extremely dynamic: developers continuously commit code and introduce new features, functionality and fixes. Hundreds of commits may enter the code-base in a single day. Therefore one of the most time-critical, yet resource-intensive tasks towards ensuring code-quality is effectively testing such large code-bases. This paper presents FastLane, a system that performs datadriven test minimization. FastLane uses light-weight machinelearning models built upon a rich history of test and commit logs to predict test outcomes. Tests for which we predict outcomes need not be explicitly run, thereby saving us precious testtime and resources. Our evaluation on a large-scale email and collaboration platform service shows that our techniques can save 18.04%, i.e., almost a fifth of test-time while obtaining a test outcome accuracy of 99.99%. [ABSTRACT FROM AUTHOR]

Side-channel attacks allow an adversary to uncover secret program data by observing the behavior of a program with respect to a resource, such as execution time, consumed memory or response size. Side-channel vulnerabilities are difficult to reason about as they involve analyzing the correlations between resource usage over multiple program paths. We present DIFFUZZ, a fuzzing-based approach for detecting side-channel vulnerabilities related to time and space. DIFFUZZ automatically detects these vulnerabilities by analyzing two versions of the program and using resource-guided heuristics to find inputs that maximize the difference in resource consumption between secretdependent paths. The methodology of DIFFUZZ is general and can be applied to programs written in any language. For this paper, we present an implementation that targets analysis of JAVA programs, and uses and extends the KELINCI and AFL fuzzers. We evaluate DIFFUZZ on a large number of JAVA programs and demonstrate that it can reveal unknown sidechannel vulnerabilities in popular applications.We also show that DIFFUZZ compares favorably against BLAZER and THEMIS, two state-of-the-art analysis tools for finding side-channels in JAVA programs. [ABSTRACT FROM AUTHOR]

Developers rely on software logs for a wide variety of tasks, such as debugging, testing, program comprehension, verification, and performance analysis. Despite the importance of logs, prior studies show that there is no industrial standard on how to write logging statements. Recent research on logs often only considers the appropriateness of a log as an individual item (e.g., one single logging statement); while logs are typically analyzed in tandem. In this paper, we focus on studying duplicate logging statements, which are logging statements that have the same static text message. Such duplications in the text message are potential indications of logging code smells, which may affect developers' understanding of the dynamic view of the system. We manually studied over 3K duplicate logging statements and their surrounding code in four large-scale open source systems: Hadoop, CloudStack, ElasticSearch, and Cassandra. We uncovered five patterns of duplicate logging code smells. For each instance of the code smell, we further manually identify the problematic (i.e., require fixes) and justifiable (i.e., do not require fixes) cases. Then, we contact developers in order to verify our manual study result. We integrated our manual study result and developers' feedback into our automated static analysis tool, DLFinder, which automatically detects problematic duplicate logging code smells.We evaluated DLFinder on the four manually studied systems and two additional systems: Camel and Wicket. In total, combining the results of DLFinder and our manual analysis, we reported 82 problematic code smell instances to developers and all of them have been fixed. [ABSTRACT FROM AUTHOR]

This paper offers practical insights and lessons learned from over five years of direct experience provisioning and supporting augmented and virtual reality equipment as lendable technology. A pragmatic exploration of one academic library's experience in the development, sustainability, and evolution of augmented and virtual reality technology and associated services. Analyzed and critiqued in comparison to traditional library materials and services, the novel library collection is bridging the gap between learning, research, and practice. Library support is proving to be critical path: from the initial development of the lending technology collections, through the collaborative development of mixed reality equipment, spaces, and software. Specific details associated with the library's current state of practice are shared, including specifics as to working systems for both the HTC Vive and Oculus Rift equipment on dedicated mobile workstations available throughout the library. Collaborations with departments including Computer Science & Engineering, as well as the School of Journalism, have proven to be a natural outcome of the library's support: joint effort resulting in the development of numerous dedicated mobile augmented and virtual reality software development stations throughout the library, and resultant exhibit development. [ABSTRACT FROM AUTHOR]

While design and designing are core elements in computer science and software engineering, conventional curricular structures do not adequately support design learning. Current methods tend to isolate the study of design within specific subject matter and lack a strong emphasis on reflection. This paper reports on insights and lessons learned from a user study in the context of ongoing work on developing an educational intervention that better supports design learning with a particular emphasis on learner-driven reflection. Insights drawn from this study relate to general aspects of design learning, such as the importance of collaborative reflection and the impact of learner perceptions regarding their abilities, as well as to specific improvements to our approach. [ABSTRACT FROM AUTHOR]

The development of discipline-specific cognitive and meta-cognitive skills is fundamental to the successful mastery of software development skills and processes. This development happens over time and is influenced by many factors, however its understanding by teachers is crucial in order to develop activities and materials to transform students from novice to expert software engineers. In this paper, we analyse the evolution of learning strategies of novice, first year students, to expert, final year students. We analyse reflections on software development processes from students in an introductory software development course, and compare them to those of final year students, in a distributed systems development course. Our study shows that computer science - specific strategies evolve as expected, with the majority of final year students including design before coding in their software development process, but that several areas still require scaffolding activities to assist in learning development. [ABSTRACT FROM AUTHOR]

In many software development projects, analysts are required to deal with systems' requirements from unfamiliar domains. Familiarity with the domain is necessary in order to get full leverage from interaction with stakeholders and for extracting relevant information from the existing project documents. Accurate and timely extraction and classification of requirements knowledge support analysts in this challenging scenario. Our approach is to mine real-time interaction records and project documents for the relevant phrasal units about the requirements related topics being discussed during elicitation. We propose to use both generative and discriminating methods. To extract the relevant terms, we leverage the flexibility and power of Weighted Finite State Transducers (WFSTs) in dynamic modelling of natural language processing tasks. We used an extended version of Support Vector Machines (SVMs) with variable-sized feature vectors to efficiently and dynamically extract and classify requirements-related knowledge from the existing documents. To evaluate the performance of our approach intuitively and quantitatively, we used edit distance and precision/recall metrics. We show in three case studies that the snippets extracted by our method are intuitively relevant and reasonably accurate. Furthermore, we found that statistical and linguistic parameters such as smoothing methods, and words contiguity and order features can impact the performance of both extraction and classification tasks. [ABSTRACT FROM AUTHOR]

Software testing is an integral part of modern software development. However, test runs can produce thousands of lines of logged output that make it difficult to find the cause of a fault in the logs. This problem is exacerbated by environmental failures that distract from product faults. In this paper we present techniques with the goal of capturing the maximum number of product faults, while flagging the minimum number of log lines for inspection. We observe that the location of a fault in a log should be contained in the lines of a failing test log. In contrast, a passing test log should not contain the lines related to a failure. Lines that occur in both a passing and failing log introduce noise when attempting to find the fault in a failing log. We introduce an approach where we remove the lines that occur in the passing log from the failing log. After removing these lines, we use information retrieval techniques to flag the most probable lines for investigation. We modify TF-IDF to identify the most relevant log lines related to past product failures. We then vectorize the logs and develop an exclusive version of KNN to identify which logs are likely to lead to product faults and which lines are the most probable indication of the failure. Our best approach, LOGFAULTFLAGGER finds 89% of the total faults and flags less than 1% of the total failed log lines for inspection. LOGFAULTFLAGGER drastically outperforms the previous work CAM. We implemented LOGFAULTFLAGGER as a tool at Ericsson where it presents fault prediction summaries to base station testers. [ABSTRACT FROM AUTHOR]

Programs often suffer from poor performance that can be fixed by relatively simple changes. Currently, developers either manually identify and fix such performance problems, or they rely on compilers to optimize their code. Unfortunately, manually fixing performance bugs is non-trivial, and compilers are limited to a predefined set of optimizations. This paper presents an approach for automatically finding and fixing performance bugs in JavaScript programs. To focus our work on relevant problems, we study 37 real-world performance bug fixes from eleven popular JavaScript projects and identify several recurring fix patterns. Based on the results of the study, we present a static analysis that identifies occurrences of common fix patterns and a fix generation technique that proposes to transform a given program into a more efficient program. Applying the fix generation technique to three libraries with known performance bugs yields fixes that are equal or equivalent to those proposed by the developers, and that lead to speedups between 10% and 25%. [ABSTRACT FROM AUTHOR]

Modern software systems are increasingly designed to be highly configurable, which increases flexibility but can make programs harder to develop, test, and analyze, e.g., how configuration options are set to reach certain locations, what characterizes the configuration space of an interesting or buggy program behavior? We introduce GenTree, a new dynamic analysis that automatically learns a program's interactions--logical formulae that describe how configuration option settings map to code coverage. GenTree uses an iterative refinement approach that runs the program under a small sample of configurations to obtain coverage data; uses a custom classifying algorithm on these data to build decision trees representing interaction candidates; and then analyzes the trees to generate new configurations to further refine the trees and interactions in the next iteration. Our experiments on 17 configurable systems spanning 4 languages show that GenTree efficiently finds precise interactions using a tiny fraction of the configuration space. [ABSTRACT FROM AUTHOR]

Smart contracts have been plagued by security incidents, which resulted in substantial financial losses. Given numerous research efforts in addressing the security issues of smart contracts, we wondered how software practitioners build security into smart contracts in practice. We performed a mixture of qualitative and quantitative studies with 13 interviewees and 156 survey respondents from 35 countries across six continents to understand practitioners' perceptions and practices on smart contract security. Our study uncovers practitioners' motivations and deterrents of smart contract security, as well as how security efforts and strategies fit into the development lifecycle. We also find that blockchain platforms have a statistically significant impact on practitioners' security perceptions and practices of smart contract development. Based on our findings, we highlight future research directions and provide recommendations for practitioners. [ABSTRACT FROM AUTHOR]

Inline assembly is still a common practice in low-level C programming, typically for efficiency reasons or for accessing specific hardware resources. Such embedded assembly codes in the GNU syntax (supported by major compilers such as GCC, Clang and ICC) have an interface specifying how the assembly codes interact with the C environment. For simplicity reasons, the compiler treats GNU inline assembly codes as blackboxes and relies only on their interface to correctly glue them into the compiled C code. Therefore, the adequacy between the assembly chunk and its interface (named compliance) is of primary importance, as such compliance issues can lead to subtle and hard-to-find bugs. We propose RUSTINA, the first automated technique for formally checking inline assembly compliance, with the extra ability to propose (proven) patches and (optimization) refinements in certain cases. RUSTINA is based on an original formalization of the inline assembly compliance problem together with novel dedicated algorithms. Our prototype has been evaluated on 202 Debian packages with inline assembly (2656 chunks), finding 2183 issues in 85 packages -- 986 significant issues in 54 packages (including major projects such as ffmpeg or ALSA), and proposing patches for 92% of them. Currently, 38 patches have already been accepted (solving 156 significant issues), with positive feedback from development teams. [ABSTRACT FROM AUTHOR]

App stores allow users to give valuable feedback on apps, and developers to find this feedback and use it for the software evolution. However, finding user feedback that matches existing bug reports in issue trackers is challenging as users and developers often use a different language. In this work, we introduce DeepMatcher, an automatic approach using state-of-the-art deep learning methods to match problem reports in app reviews to bug reports in issue trackers. We evaluated DeepMatcher with four open-source apps quantitatively and qualitatively. On average, DeepMatcher achieved a hit ratio of 0.71 and a Mean Average Precision of 0.55. For 91 problem reports, DeepMatcher did not find any matching bug report. When manually analyzing these 91 problem reports and the issue trackers of the studied apps, we found that in 47 cases, users actually described a problem before developers discovered and documented it in the issue tracker. We discuss our findings and different use cases for DeepMatcher. [ABSTRACT FROM AUTHOR]

Online collaboration platforms such as GitHub have provided software developers with the ability to easily reuse and share code between repositories. With clone-and-own and forking becoming prevalent, maintaining these shared files is important, especially for keeping the most up-to-date version of reused code. Different to related work, we propose the concept of meta-maintenance--i.e., tracking how the same files evolve in different repositories with the aim to provide useful maintenance opportunities to those files. We conduct an exploratory study by analyzing repositories from seven different programming languages to explore the potential of meta-maintenance. Our results indicate that a majority of active repositories on GitHub contains at least one file which is also present in another repository, and that a significant minority of these files are maintained differently in the different repositories which contain them. We manually analyzed a representative sample of shared files and their variants to understand which changes might be useful for meta-maintenance. Our findings support the potential of meta-maintenance and open up avenues for future work to capitalize on this potential. [ABSTRACT FROM AUTHOR]