Automated Workarounds from Java Program Specifications based on SAT Solving

The failures that bugs in software lead to can sometimes be bypassed by the so-called workarounds: when a (faulty) routine fails, alternative routines that the system offers can be used in place of the failing one, to circumvent the failure. Existing approaches to workaround-based system recovery consider workarounds that are produced from equivalent method sequences, automatically computed from user-provided abstract models, or directly produced from user-provided equivalent sequences of operations. In this paper, we present two techniques for computing workarounds from Java code equipped with formal specifications, that improve previous approaches in two respects. First, the particular state where the failure originated is actively involved in computing workarounds, thus leading to repairs that are more state specific. Second, our techniques automatically compute workarounds on concrete program state characterizations, avoiding abstract software models and user-provided equivalences. The first technique uses SAT solving to compute a sequence of methods that is equivalent to a failing method on a specific failing state, but which can also be generalized to schemas for workaround reuse. The second technique directly exploits SAT to circumvent a failing method, building a state that mimics the (correct) behaviour of a failing routine, from a specific program state too. We perform an experimental evaluation based on case studies involving implementations of collections and a library for date arithmetic, showing that the techniques can effectively compute workarounds from complex contracts in an important number of cases, in time that makes them feasible to be used for run-time repairs. Our results also show that our state-specific workarounds enable us to produce repairs in many cases where previous workaround-based approaches are inapplicable.Fil: Uva, Marcelo Ariel. Universidad Nacional de Río Cuarto; ArgentinaFil: Ponzio, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto; ArgentinaFil: Regis, Germán. Universidad Nacional de Río Cuarto; ArgentinaFil: Aguirre, Nazareno Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto; ArgentinaFil: Frias, Marcelo Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Instituto Tecnológico de Buenos Aires; Argentin

Software quality tools and techniques presented in FASE’17

Software quality assurance aims to ensure that the software product meets the quality standards expected by the customer. This special issue of Software Tools for Technology Transfer is concerned with the foundations on which software quality assurance is built. It introduces the papers that focus on this topic and that have been selected from the 20th International Conference on Fundamental Approaches to Software Engineering (FASE’17)

Automated Fixing of Programs with Contracts

This paper describes AutoFix, an automatic debugging technique that can fix faults in general-purpose software. To provide high-quality fix suggestions and to enable automation of the whole debugging process, AutoFix relies on the presence of simple specification elements in the form of contracts (such as pre- and postconditions). Using contracts enhances the precision of dynamic analysis techniques for fault detection and localization, and for validating fixes. The only required user input to the AutoFix supporting tool is then a faulty program annotated with contracts; the tool produces a collection of validated fixes for the fault ranked according to an estimate of their suitability. In an extensive experimental evaluation, we applied AutoFix to over 200 faults in four code bases of different maturity and quality (of implementation and of contracts). AutoFix successfully fixed 42% of the faults, producing, in the majority of cases, corrections of quality comparable to those competent programmers would write; the used computational resources were modest, with an average time per fix below 20 minutes on commodity hardware. These figures compare favorably to the state of the art in automated program fixing, and demonstrate that the AutoFix approach is successfully applicable to reduce the debugging burden in real-world scenarios.Comment: Minor changes after proofreadin

Automatic Software Repair: a Bibliography

This article presents a survey on automatic software repair. Automatic software repair consists of automatically finding a solution to software bugs without human intervention. This article considers all kinds of repairs. First, it discusses behavioral repair where test suites, contracts, models, and crashing inputs are taken as oracle. Second, it discusses state repair, also known as runtime repair or runtime recovery, with techniques such as checkpoint and restart, reconfiguration, and invariant restoration. The uniqueness of this article is that it spans the research communities that contribute to this body of knowledge: software engineering, dependability, operating systems, programming languages, and security. It provides a novel and structured overview of the diversity of bug oracles and repair operators used in the literature

Reparación de programas aplicando templates: generando workarounds permanentes a través de SAT

La aplicación de procesos modernos y sistemáticos en el desarrollo de sistemas informáticos con estrictos estándares de calidad no ha podido evitar la presencia de defectos en el software. A pesar de extensas test-suites, un alto porcentaje de sistemas son implantados con fallas. El desarrollo de técnicas de reparación de programas ha cobrado gran importancia en esta última década. El concepto de workaround ha sido utilizado por diversos enfoques para la reparación de programas. Un workaround aprovecha la redundancia implícita en un sistema con el propósito de evitar fallas detectadas en runtime. A partir de una técnica de cómputo automático de state-bound workarounds (workarounds dependientes de estado) que utiliza SAT-Solving, se propone un procedimiento de búsqueda de workaround templates independientes de estado, es decir, state-free workarounds que permitan mejorar los tiempos de reparación de programas.XVI Workshop Ingeniería de Software.Red de Universidades con Carreras en Informátic

Reparación de programas aplicando templates: generando workarounds permanentes a través de SAT

La aplicación de procesos modernos y sistemáticos en el desarrollo de sistemas informáticos con estrictos estándares de calidad no ha podido evitar la presencia de defectos en el software. A pesar de extensas test-suites, un alto porcentaje de sistemas son implantados con fallas. El desarrollo de técnicas de reparación de programas ha cobrado gran importancia en esta última década. El concepto de workaround ha sido utilizado por diversos enfoques para la reparación de programas. Un workaround aprovecha la redundancia implícita en un sistema con el propósito de evitar fallas detectadas en runtime. A partir de una técnica de cómputo automático de state-bound workarounds (workarounds dependientes de estado) que utiliza SAT-Solving, se propone un procedimiento de búsqueda de workaround templates independientes de estado, es decir, state-free workarounds que permitan mejorar los tiempos de reparación de programas.XVI Workshop Ingeniería de Software.Red de Universidades con Carreras en Informátic

The 1st Verified Software Competition, Extended Experience Report

We, the organizers and participants, report our experiences from the 1st Veried Software Competition, held in August 2010 in Edinburgh at the VSTTE 2010 conferenc

The 1st Verified Software Competition, Extended Experience Report

We, the organizers and participants, report our experiences from the 1st Veried Software Competition, held in August 2010 in Edinburgh at the VSTTE 2010 conferenc

Contract-driven data structure repair : a novel approach for error recovery

textSoftware systems are now pervasive throughout our world. The reliability of these systems is an urgent necessity. A large degree of research effort on increasing software reliability is dedicated to requirements, architecture, design, implementation and testing---activities that are performed before system deployment. While such approaches have become substantially more advanced, software remains buggy and failures remain expensive. We take a radically different approach to reliability from previous approaches, namely contract-driven data structure repair for runtime error recovery, where erroneous executions of deployed software are corrected on-the-fly using rich behavioral contracts. Our key insight is to transform the software contract---which gives a high level description of the expected behavior---to an efficient implementation which repairs the erroneous data structures in the program state upon an error. To improve efficiency, scalability, and effectiveness of repair, in addition to rich behavioral contracts, we leverage the current erroneous state, dynamic behavior of the program, as well as repair history and abstraction. A core technical problem our approach to repair addresses is construction of structurally complex data that satisfy desired properties. We present a novel structure generation technique based on dynamic programming---a classic optimization approach---to utilize the recursive nature of the structures. We use our technique for constraint-based testing. It provides better scalability than previous work. We applied it to test widely-used web browsers and found some known and unknown bugs. Our use of dynamic programming in structure generation opens a new future direction to tackle the scalability problem of data structure repair. This research advances our ability to develop correct programs. For programs that already have contracts, error recovery using our approach can come at a low cost. The same contracts can be used for systematically testing code before deployment using existing as well as our new techniques. Thus, we enable a novel unification of software verification and error recovery.Electrical and Computer Engineerin