Large Language Models (LLMs) have achieved significant progress in language understanding and reasoning. Evaluating and analyzing their logical reasoning abilities has therefore become essential. However, existing datasets and benchmarks are often limited to overly simplistic, unnatural, or contextually constrained examples. In response to the growing demand, we introduce SMARTYPAT-BENCH, a challenging, naturally expressed, and systematically labeled benchmark derived from real-world high-quality Reddit posts containing subtle logical fallacies. Unlike existing datasets and benchmarks, it provides more detailed annotations of logical fallacies and features more diverse data. To further scale up the study and address the limitations of manual data collection and labeling, such as fallacy-type imbalance and labor-intensive annotation, we introduce SMARTYPAT, an automated framework powered by logic programming-based oracles. SMARTYPAT utilizes Prolog rules to systematically generate logically fallacious statements, which are then refined into fluent natural language sentences by LLMs, ensuring precise fallacy rep- resentation. Extensive evaluation demonstrates that SMARTYPAT produces fallacies comparable in subtlety and quality to human-generated content and significantly outperforms baseline methods. Finally, experiments reveal insights into LLM capabilities, highlighting that while excessive reasoning steps hinder fallacy detection accuracy, structured reasoning enhances fallacy categorization performance.

Large language model (LLM)-based multi-agent systems have emerged as a powerful paradigm for enabling autonomous agents to solve complex tasks. As these systems scale in complexity, cost becomes an important consideration for practical deployment. However, existing work rarely addresses how to structure multi-agent systems under explicit budget constraints. In this paper, we propose BAMAS, a novel approach for building multi-agent systems with budget awareness. BAMAS first selects an optimal set of LLMs by formulating and solving an Integer Linear Programming problem that balances performance and cost. It then determines how these LLMs should collaborate by leveraging a reinforcement learning-based method to select the interaction topology. Finally, the system is instantiated and executed based on the selected agents and their collaboration topology. We evaluate BAMAS on three representative tasks and compare it with state-of-the-art agent construction methods. Results show that BAMAS achieves comparable performance while reducing cost by up to 86%.

Zhenhao Zhou, Zhuochen Huang, Yike He, Chong Wang, Jiajun Wang, Yijian Wu, Xin Peng, Yiling Lou. Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers). 2026.

Alperen Yildiz, Sin G Teo, Yiling Lou, Yebo Feng, Chong Wang, Dinil Mon Divakaran. Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers). 2025.

Python's dynamic typing system offers flexibility and expressiveness but can lead to type-related errors, prompting the need for automated type inference to enhance type hinting. While existing learning-based approaches show promising inference accuracy, they struggle with practical challenges in comprehensively handling various types, including complex parameterized types and (unseen) user-defined types. In this paper, we introduce TIGER, a two-stage generating-then-ranking (GTR) framework, designed to effectively handle Python's diverse type categories. TIGER leverages fine-tuned pre-trained code models to train a generative model with a span masking objective and a similarity model with a contrastive training objective. This approach allows TIGER to generate a wide range of type candidates, including complex parameterized types in the generating stage, and accurately rank them with user-defined types in the ranking stage. Our evaluation on the ManyTypes4Py dataset shows TIGER's advantage over existing methods in various type categories, notably improving accuracy in inferring user-defined and unseen types by 11.2% and 20.1% respectively in Top-5 Exact Match. Moreover, the experimental results not only demonstrate TIGER's superior performance and efficiency, but also underscore the significance of its generating and ranking stages in enhancing automated type inference.

Resource leaks, caused by resources not being released after acquisition, often lead to performance issues and system crashes. Existing static detection techniques rely on mechanical matching of predefined resource acquisition/release APIs and null-checking conditions to find unreleased resources, suffering from both (1) false negatives caused by the incompleteness of predefined resource acquisition/release APIs and (2) false positives caused by the incompleteness of resource reachability validation identification. To overcome these challenges, we propose InferROI, a novel approach that leverages the exceptional code comprehension capability of large language models (LLMs) to directly infer resource-oriented intentions (acquisition, release, and reachability validation) in code. InferROI first prompts the LLM to infer involved intentions for a given code snippet, and then incorporates a two-stage static analysis approach to check control-flow paths for resource leak detection based on the inferred intentions. We evaluate the effectiveness of InferROI in both resource-oriented intention inference and resource leak detection. Experimental results on the DroidLeaks and JLeaks datasets demonstrate InferROI achieves promising bug detection rate (59.3% and 62.5%) and false alarm rate (18.6% and 19.5%). Compared to three industrial static detectors, InferROI detects 14~45 and 149~485 more bugs in DroidLeaks and JLeaks, respectively. When applied to real-world open-source projects, InferROI identifies 29 unknown resource leak bugs (verified by authors), with 7 of them being confirmed by developers. In addition, the results of an ablation study underscores the importance of combining LLM-based inference with static analysis. Finally, manual annotation indicated that InferROI achieved a precision of 74.6% and a recall of 81.8% in intention inference, covering more than 60% resource types involved in the datasets.

LLM-based agent systems are emerging as a new software paradigm and have been widely adopted across diverse domains such as medicine, robotics, and programming. However, maintaining these systems requires substantial effort, as they are inevitably prone to bugs and continually evolve to meet changing external requirements. Therefore, automatically resolving agent issues (i.e.,bug reports or feature requests) is a crucial and challenging task. While recent software engineering (SE) agents (e.g., SWE-agent) have shown promise in addressing issues in traditional software systems, it remains unclear how effectively they can resolve real-world issues in agent systems, which differ significantly from traditional software. To fill this gap, we first manually analyze 201 real-world agent issues and identify common categories of agent issues. We then spend 500 person-hours constructing AgentIssue-bench, a reproducible benchmark comprising 50 agent issue resolution tasks (each with an executable environment and failure-triggering tests). We further evaluate state-of-the-art SE agents on AgentIssue-bench and reveal their limited effectiveness (\.e., with only 0.67% - 4.67% resolution rates). These results underscore the unique challenges of maintaining agent systems compared to traditional software, highlighting the need for further research to develop advanced SE agents for resolving agent issues.

Automated Program Repair (APR) holds the promise of alleviating the burden of debugging and fixing software bugs. Despite this, developers still need to manually inspect each patch to confirm its correctness, which is tedious and time-consuming. This challenge is exacerbated in the presence of plausible patches, which accidentally pass test cases but may not correctly fix the bug. To address this challenge, we propose an interactive approach called iFix to facilitate patch understanding and comparison based on their runtime difference. iFix performs static analysis to identify runtime variables related to the buggy statement and captures their runtime values during execution for each patch. These values are then aligned across different patch candidates, allowing users to compare and contrast their runtime behavior. To evaluate iFix , we conducted a within-subjects user study with 28 participants. Compared with manual inspection and a state-of-the-art interactive patch filtering technique, iFix reduced participants’ task completion time by 36% and 33% while also improving their confidence by 50% and 20%, respectively. Besides, quantitative experiments demonstrate that iFix improves the ranking of correct patches by at least 39% compared with other patch ranking methods and is generalizable to different APR tools.

Prevalent Fault Localization (FL) techniques rely on tests to localize buggy program elements. Tests could be treated as fuel to further boost FL by providing more debugging information. Therefore, it is highly valuable to measure the Fault Diagnosis Capability (FDC) of a test for diagnosing faults, so as to select or generate tests to better help FL (i.e., FL-oriented test selection or FL-oriented test generation). To this end, researchers have proposed many FDC metrics, which serve as the selection criterion in FL-oriented test selection or the fitness function in FL-oriented test generation. Existing FDC metrics can be classified into result-agnostic and result-aware metrics depending on whether they take test results (i.e., passing or failing) as input. Although result-aware metrics perform better in test selection, they have restricted applications due to the input of test results, e.g., they cannot be applied to guide test generation. Moreover, all the existing FDC metrics are designed based on some pre-defined heuristics and have achieved limited FL performance due to their inaccuracy. To address these issues, in this article, we reconsider result-agnostic metrics (i.e., metrics that do not take test results as input), and propose a novel result-agnostic metric RLFDC which predicts FDC values of tests through reinforcement learning. In particular, we treat FL results as reward signals, and train an FDC prediction model with the direct FL feedback to automatically learn a more accurate measurement rather than design one based on pre-defined heuristics. Finally, we evaluate the proposed RLFDC on Defects4J by applying the studied metrics to test selection and generation. According to the experimental results, the proposed RLFDC outperforms all the result-agnostic metrics in both test selection and generation, e.g., when applied to selecting human-written tests, RLFDC achieves 28.2% and 21.6% higher acc@1 and mAP values compared to the state-of-the-art result-agnostic metric TfD. Besides, RLFDC even achieves competitive performance compared to the state-of-the-art result-aware metric FDG in test selection.

Fault Localization (FL) is an essential step during the debugging process. With the strong capabilities of code comprehension, the recent Large Language Models (LLMs) have demonstrated promising performance in diagnosing bugs in the code. Nevertheless, due to LLMs’ limited performance in handling long contexts, existing LLM-based fault localization remains on localizing bugs within asmall code scope(i.e., a method or a class), which struggles to diagnose bugs for alarge code scope(i.e., an entire software system). To address the limitation, this paper presents SoapFL, which builds an LLM-driven standard operating procedure (SOP) to automatically localize buggy methods from the entire software. By simulating the behavior of a human developer, SoapFL models the FL task as a three-step process, which involves comprehension, navigation, and confirmation. Within specific steps, SoapFL provides useful test behavior or coverage information to LLM through program analysis. Particularly, we adopt a series of auxiliary strategies such as Test Behavior Tracking, Document-Guided Search, and Multi-Round Dialogue to overcome the challenges in each step. The evaluation on the widely used Defects4J-V1.2.0 benchmark shows that SoapFL can localize 175 out of 395 bugs within Top-1, which outperforms the other LLM-based approaches and exhibits complementarity to the state-of-the-art learning-based techniques. Additionally, we confirm the indispensability of the components in SoapFL with the ablation study and demonstrate the usability of SoapFL through a user study. Finally, the cost analysis shows that SoapFL spends an average of only 0.081 dollars and 92 seconds for a single bug.

Recently, many large language models (LLMs) have been proposed, showing advanced proficiency in code generation. Meanwhile, many efforts have been dedicated to evaluating LLMs on code generation benchmarks such as HumanEval. Although being very helpful for comparing different LLMs, existing evaluation focuses on a simple code generation scenario (i.e., function-level or statement-level code generation), which mainly asks LLMs to generate one single code unit (e.g., a function or a statement) for the given natural language description. Such evaluation focuses on generating independent and often small-scale code units, thus leaving it unclear how LLMs perform in real-world software development scenarios.

In recent years, Automated Program Repair (APR) has been extensively studied in academia and even drawn wide attention from the industry. However, APR techniques can be extremely time consuming since (1) a large number of patches can be generated for a given bug, and (2) each patch needs to be executed on the original tests to ensure its correctness. In the literature, various techniques (e.g., based on learning, mining, and constraint solving) have been proposed/studied to reduce the number of patches. Intuitively, every patch can be treated as a software revision during regression testing; thus, traditional Regression Test Selection (RTS) techniques can be leveraged to only execute the tests affected by each patch (as the other tests would keep the same outcomes) to further reduce patch execution time. However, few APR systems actually adopt RTS and there is still a lack of systematic studies demonstrating the benefits of RTS and the impact of different RTS strategies on APR. To this end, this article presents the first extensive study of widely used RTS techniques at different levels (i.e., class/method/statement levels) for 12 state-of-the-art APR systems on over 2M patches. Our study reveals various practical guidelines for bridging the gap between APR and regression testing, including: (1) the number of patches widely used for measuring APR efficiency can incur skewed conclusions, and the use of inconsistent RTS configurations can further skew the conclusions; (2) all studied RTS techniques can substantially improve APR efficiency and should be considered in future APR work; (3) method- and statement-level RTS outperform class-level RTS substantially and should be preferred; (4) RTS techniques can substantially outperform state-of-the-art test prioritization techniques for APR, and combining them can further improve APR efficiency; and (5) traditional Regression Test Prioritization (RTP) widely studied in regression testing performs even better than APR-specific test prioritization when combined with most RTS techniques. Furthermore, we also present the detailed impact of different patch categories and patch validation strategies on our findings.

Commit messages summarize code changes and help developers understand the intention. To alleviate human efforts in writing commit messages, researchers have proposed various automated commit message generation techniques, among which learning-based techniques have achieved great success in recent years. However, existing evaluation on learning-based commit message generation relies on the automatic metrics (e.g., BLEU) widely used in natural language processing (NLP) tasks, which are aggregated scores calculated based on the similarity between generated commit messages and the ground truth. Therefore, it remains unclear what generated commit messages look like and what kind of commit messages could be precisely generated by existing learning-based techniques. To fill this knowledge gap, this work performs the first study to systematically investigate the detailed commit messages generated by learning-based techniques. In particular, we first investigate the frequent patterns of the commit messages generated by state-of-the-art learning-based techniques. Surprisingly, we find the majority (~90%) of their generated commit messages belong to simple patterns (i.e., addition/removal/fix/avoidance patterns). To further explore the reasons, we then study the impact of datasets, input representations, and model components. We surprisingly find that existing learning-based techniques have competitive performance even when the inputs are only represented by change marks (i.e., “+”/“-”/“ ”), It indicates that existing learning-based techniques poorly utilize syntax and semantics in the code while mostly focusing on change marks, which could be the major reason for generating so many pattern-matching commit messages. We also find that the pattern ratio in the training set might also positively affect the pattern ratio of generated commit messages; and model components might have different impact on the pattern ratio.

Automated Program Repair (APR) improves soft-ware reliability by generating patches for a buggy program automatically. Recent APR techniques leverage deep learning (DL) to build models to learn to generate patches from existing patches and code corpora. While promising, DL-based APR techniques suffer from the abundant syntactically or semantically incorrect patches in the patch space. These patches often disobey the syntactic and semantic domain knowledge of source code and thus cannot be the correct patches to fix a bug. We propose a DL-based APR approach KNOD, which in-corporates domain knowledge to guide patch generation in a direct and comprehensive way. KNOD has two major novelties, including (1) a novel three-stage tree decoder, which directly generates Abstract Syntax Trees of patched code according to the inherent tree structure, and (2) a novel domain-rule distillation, which leverages syntactic and semantic rules and teacher-student distributions to explicitly inject the domain knowledge into the decoding procedure during both the training and inference phases. We evaluate KNOD on three widely-used benchmarks. KNOD fixes 72 bugs on the Defects4J v1.2, 25 bugs on the QuixBugs, and 50 bugs on the additional Defects4J v2.0 benchmarks, outperforming all existing APR tools.

Collaborative development is critical to improve the productivity. Multiple contributors work simultaneously on the same project and might make changes to the same code locations. This can cause conflicts and require manual intervention from developers to resolve them. To alleviate the human efforts of manual conflict resolution, researchers have proposed various automatic techniques. More recently, deep learning models have been adopted to solve this problem and achieved state-of-the-art performance. However, these techniques leverage classification to combine the existing elements of input. The classification- based models cannot generate new tokens or produce flexible combinations, and have a wrong hypothesis that fine-grained conflicts of one single coarse-grained conflict are independent. In this work, we propose to generate the resolutions of merge conflicts from a totally new perspective, that is, generation, and we present a conflict resolution technique, MergeGen. First, we design a structural and fine-grained conflict-aware representation for the merge conflicts. Then, we propose to leverage an encoder- decoder-based generative model to process the designed conflict representation and generate the resolutions auto-regressively. We further perform a comprehensive study to evaluate the effectiveness of MergeGen. The quantitative results show that MergeGen outperforms the state-of-the-art (SOTA) techniques from both precision and accuracy. Our evaluation on multiple programming languages verifies the good generalization ability of MergeGen. In addition, the ablation study shows that the major component of our technique makes a positive contribution to the performance of MergeGen, and the granularity analysis reveals the high tolerance of MergeGen to coarse-grained conflicts. Moreover, the analysis on generating new tokens further proves the advance of generative models.

Automated code generation has been extensively studied in recent literature. In this work, we first survey 66 participants to motivate a more pragmatic code generation scenario, i.e., library-oriented code generation, where the generated code should implement the functionally of the natural language query with the given library. We then revisit existing learning-based code generation techniques and find they have limited effectiveness in such a library-oriented code generation scenario. To address this limitation, we propose a novel library-oriented code generation technique, CodeGen4Libs, which incorporates two stages: import generation and code generation. The import generation stage generates import statements for the natural language query with the given third-party libraries, while the code generation stage generates concrete code based on the generated imports and the query. To evaluate the effectiveness of our approach, we conduct extensive experiments on a dataset of 403,780 data items. Our results demonstrate that CodeGen4Libs outperforms baseline models in both import generation and code generation stages, achieving improvements of up to 97.4% on EM (Exact Match), 54.5% on BLEU, and 53.5% on Hit@All. Overall, our proposed CodeGen4Libs approach shows promising results in generating high-quality code with specific third-party libraries, which can improve the efficiency and effectiveness of software development.

As basic elements in program, variables convey essential information that is critical for program comprehension and maintenance. However, understanding the meanings of variables in program is not always easy for developers, since poor-quality variable names are prevalent while such variable are less informative for program comprehension. Therefore, in this paper, we target at generating concise natural language explanations for variables to facilitate program comprehension. In particular, there are two challenges in variable explanation generation, including the lack of training data and the association with complex code contexts around the variable. To address these issues, we propose a novel approach ZeroVar,which leverages code pre-trained models and zero-shot prompt learning to generate explanations for the variable based on its code context. ZeroVarcontains two stages: (i) a pre-training stage that continually pre-trains a base model (i.e., CodeT5) to recover the randomly-masked parameter descriptions in method docstrings; and (ii) a zero-shot prompt learning stage that leverages the pre-trained model to generate explanations for a given variable via the prompt constructed with the variable and its belonging method context. We then extensively evaluate the quality and usefulness of the variable explanations generated by ZeroVar.We construct an evaluation dataset of 773 variables and their reference explanations. Our results show that ZeroVarcan generate higher-quality explanations than baselines, not only on automated metrics such as BLEU and ROUGE, but also on human metrics such as correctness, completeness, and conciseness. Moreover, we further assess the usefulness of ZeroVAR-generated explanations on two downstream tasks related to variable naming quality, i.e., abbreviation expansion and spelling correction. For abbreviation expansion, the generated variable explanations can help improve the present rate (+13.1%), precision (+3.6%), and recall (+10.0%) of the state-of-the-art abbreviation explanation approach. For spelling correction, by using the generated explanations we can achieve higher hit@1 (+162.9(%) and hit@3 (+49.6%) than the recent variable representation learning approach.

Library migration, which replaces the current library with a different one to retain the same software behavior, is common in software evolution. An essential part of this is finding an analogous API for the desired functionality. However, due to the multitude of libraries/APIs, manually finding such an API is time-consuming and error-prone. Researchers created automated analogical API recommendation techniques, notably documentation-based methods. Despite potential, these methods have limitations, e.g., incomplete semantic understanding in documentation and scalability issues. In this study, we present KGE4AR, a novel documentation-based approach using knowledge graph (KG) embedding for recommending analogical APIs during library migration. KGE4AR introduces a unified API KG to comprehensively represent documentation knowledge, capturing high-level semantics. It further embeds this unified API KG into vectors for efficient, scalable similarity calculation. We assess KGE4AR with 35,773 Java libraries in two scenarios, with and without target libraries. KGE4AR notably outperforms state-of-the-art techniques (e.g., 47.1%-143.0% and 11.7%-80.6% MRR improvements), showcasing scalability with growing library counts.

Fixing crashes is challenging, and developers often discuss their encountered crashes and refer to similar crashes and solutions on online Q&A forums (e.g., Stack Overflow). However, a crash often involves very complex contexts, which includes different contextual elements, e.g., purposes, environments, code, and crash traces. Existing crash solution recommendation or general solution recommendation techniques only use an incomplete context or treat the entire context as pure texts to search relevant solutions for a given crash, resulting in inaccurate recommendation results. In this work, we propose a novel crash solution knowledge graph (KG) to summarize the complete crash context and its solution with a graph-structured representation. To construct the crash solution KG automatically, we propose to leverage prompt learning to construct the KG from SO threads with a small set of labeled data. Based on the constructed KG, we further propose a novel KG-based crash solution recommendation technique KG4CraSolver, which precisely finds the relevant SO thread for an encountered crash by finely analyzing and matching the complete crash context based on the crash solution KG. The evaluation results show that the constructed KG is of high quality and KG4CraSolver outperforms baselines in terms of all metrics (e.g., 13.4%-113.4% MRR improvements). Moreover, we perform a user study and find that KG4CraSolver helps participants find crash solutions 34.4% faster and 63.3% more accurately.

Resource leaks, which are caused by acquired resources not being released, often result in performance degradation and system crashes. Resource leak detection relies on two essential components: identifying potential Resource Acquisition and Release (RAR) API pairs, and subsequently analyze code to uncover instances where the corresponding release API call is absent after an acquisition API call. Yet, existing techniques confine themselves to an incomplete pair pool, either pre-defined manually or mined from project-specific code corpus, thus limiting coverage across libraries/APIs and po- tentially overlooking latent resource leaks.

Automated Program Repair (APR) techniques have drawn wide attention from both academia and industry. Meanwhile, one main limitation with the current state-of-the-art APR tools is that patches passing all the original tests are not necessarily the correct ones wanted by developers, i.e., the plausible patch problem. To date, various Patch-Correctness Checking (PCC) techniques have been proposed to address this important issue. However, they are only evaluated on very limited datasets as the APR tools used for generating such patches can only explore a small subset of the search space of possible patches, posing serious threats to external validity to existing PCC studies. In this paper, we construct an extensive PCC dataset, PraPatch (the largest manually labeled PCC dataset to our knowledge), to revisit all nine state-of-the-art PCC techniques. More specifically, our PCC dataset PraPatch includes 1,988 patches generated from the recent PraPR APR tool, which leverages highly-optimized bytecode-level patch executions and can exhaustively explore all possible plausible patches within its large predefined search space (including well-known fixing patterns from various prior APR tools). Our extensive study of representative PCC techniques on PraPatch has revealed various findings, including: 1) the assumption made by existing static PCC techniques that correct patches are more similar to buggy code than incorrect plausible patches no longer holds, 2) state-of-the-art learning-based techniques tend to suffer from the dataset overfitting problem, 3) while dynamic techniques overall retain their effectiveness on our new dataset, their performance drops substantially on patches with more complicated changes and 4) the very recent naturalness-based techniques can substantially outperform traditional static techniques and could be a promising direction for PCC. Based on our findings, we also provide various guidelines/suggestions for advancing PCC in the near future.

Commit messages summarize code changes of each commit in natural language, which help developers understand code changes without digging into detailed implementations and play an essential role in comprehending software evolution. To alleviate human efforts in writing commit messages, researchers have proposed various automated techniques to generate commit messages, including template-based, information retrieval-based, and learning-based techniques. Although promising, previous techniques have limited effectiveness due to their coarse-grained code change representations.

Unit testing could be used to validate the correctness of basic units of the software system under test. To reduce manual efforts in conducting unit testing, the research community has contributed with tools that automatically generate unit test cases, including test inputs and test oracles (e.g., assertions). Recently, ATLAS, a deep learning (DL) based approach, was proposed to generate assertions for a unit test based on other already written unit tests. Despite promising, the effectiveness of ATLAS is still limited. To improve the effectiveness, in this work, we make the first attempt to leverage Information Retrieval (IR) in assertion generation and propose an IR-based approach, including the technique of IR-based assertion retrieval and the technique of retrieved-assertion adaptation. In addition, we propose an integration approach to combine our IR-based approach with a DL-based approach (e.g., ATLAS) to further improve the effectiveness. Our experimental results show that our IR-based approach outperforms the state-of-the-art DL-based approach, and integrating our IR-based approach with the DL-based approach can further achieve higher accuracy. Our results convey an important message that information retrieval could be competitive and worthwhile to pursue for software engineering tasks such as assertion generation, and should be seriously considered by the research community given that in recent years deep learning solutions have been over-popularly adopted by the research community for software engineering tasks.

Automated debugging techniques, including fault localization and program repair, have been studied for over a decade. However, the only existing connection between fault localization and program repair is that fault localization computes the potential buggy elements for program repair to patch. Recently, a pioneering work, ProFL, explored the idea ofunified debuggingto unify fault localization and program repair in the other direction for the first time to boost both areas. More specifically, ProFL utilizes the patch execution results from one state-of-the-art repair system, PraPR, to help improve state-of-the-art fault localization. In this way, ProFL not only improves fault localization formanual repair, but also extends the application scope ofautomated repairto all possible bugs (not only the small ratio of bugs that repair systems can automatically fix). However, ProFL only considers one program repair system (i.e., PraPR), and it is not clear how other existing program repair systems based on different designs contribute to unified debugging. In this work, we perform an extensive study of the unified debugging approach on 16 state-of-the-art program repair systems for the first time. Our initial experimental results on the widely studied Defects4J benchmark suite reveal various practical guidelines for unified debugging, such as (1) nearly all 16 studied repair systems positively contribute to unified debugging despite their varying repair capabilities, (2) repair systems targeting multi-edit patches can bring extraneous noise into unified debugging, (3) repair systems with more executed/plausible patches tend to perform better for unified debugging, (4) unified debugging effectiveness does not rely on the availability of correct patches from automated repair, and (5) we propose a new unified debugging technique, UniDebug++, which localizes over 20% more bugs within Top-1 than state-of-the-art unified debugging technique ProFL (evaluated against four Defects4J subjects). Furthermore, we conduct more comprehensive studies to extend the above experiments to make the following additional contributions: we (6) further perform an extensive study on 76.3% additional buggy versions from Defects4J (for Closure and Mockito) and confirm that UniDebug++ again outperforms ProFL by localizing 185 (out of 395 in total) bugs within Top-1, 14% more than ProFL, (7) investigate the impact of 33 SBFL formulae on unified debugging and observe that UniDebug++ consistently improves upon all formulae, e.g., 61% and 53% average improvement on MFR / MAR, (8) demonstrate that UniDebug++ can substantially boost state-of-the-art learning-based method-level fault localization techniques, (9) extend unified debugging to the statement level for first time and observe that UniDebug++ localizes 78 (out of 395 in total) bugs within Top-1 (22% more bugs than ProFL) and outperforms state-of-the-art learning-based fault localization techniques by 30%, and finally (10) propose a new technique, UniDebug+$^\star$, based on detailed patch statistics, to improve upon UniDebug++, e.g., further localizing up to 9% more bugs within Top-1 than UniDebug++.

Deep learning (DL) is moving its step into a growing number of mobile software applications. These software applications, named as DL based mobile applications (abbreviated as mobile DL apps) integrate DL models trained using large-scale data with DL programs. A DL program encodes the structure of a desirable DL model and the process by which the model is trained using training data. Due to the increasing dependency of current mobile apps on DL, software engineering (SE) for mobile DL apps has become important. However, existing efforts in SE research community mainly focus on the development of DL models and extensively analyze faults in DL programs. In contrast, faults related to the deployment of DL models on mobile devices (named as deployment faults of mobile DL apps) have not been well studied. Since mobile DL apps have been used by billions of end users daily for various purposes including for safety-critical scenarios, characterizing their deployment faults is of enormous importance. To fill in the knowledge gap, this paper presents the first comprehensive study to date on the deployment faults of mobile DL apps. We identify 304 real deployment faults from Stack Overflow and GitHub, two commonly used data sources for studying software faults. Based on the identified faults, we construct a fine-granularity taxonomy consisting of 23 categories regarding to fault symptoms and distill common fix strategies for different fault symptoms. Furthermore, we suggest actionable implications and research avenues that can potentially facilitate the deployment of DL models on mobile devices.

It is widely recognized that patches generated by program repair tools have to be correct to be useful. However, it is fundamentally difficult to ensure the correctness of the patches. Many tools generate only the patches that are highly likely to be correct by taking conservative strategies which inevitably limit the recall of APR approaches. While the recall of APR can potentially be improved by relaxing the requirement on precision, more incorrect patches may also be generated. In this paper, we conjecture that reviewing incorrect patches also helps developers to understand the bug, and with proper tool support, reviewing incorrect patches would at least not reduce the repair performance. To evaluate this, we propose an interactive patch filtering approach to facilitate developers in the patch review process via effectively filtering out groups of incorrect patches. We implemented the approach as an Eclipse plugin, InPaFer, and evaluated the effectiveness and usefulness with a mixed-method evaluation. The results show that our approach improves the repair performance of developers, with 62.5% more successfully repaired bugs and 25.3% less debugging time. In particular, even if all generated patches are incorrect, the performance of developers would not be significantly reduced, and could still be improved. Our work provides a new way of thinking for the APR research.

Coverage-based fault localization has been extensively studied in the literature due to its effectiveness and lightweightness for real-world systems. However, existing techniques often utilize coverage in an oversimplified way by abstracting detailed coverage into numbers of tests or boolean vectors, thus limiting their effectiveness in practice. In this work, we present a novel coverage-based fault localization technique, GRACE, which fully utilizes detailed coverage information with graph-based representation learning. Our intuition is that coverage can be regarded as connective relationships between tests and program entities, which can be inherently and integrally represented by a graph structure: with tests and program entities as nodes, while with coverage and code structures as edges. Therefore, we first propose a novel graph-based representation to reserve all detailed coverage information and fine-grained code structures into one graph. Then we leverage Gated Graph Neural Network to learn valuable features from the graph-based coverage representation and rank program entities in a listwise way. Our evaluation on the widely used benchmark Defects4J (V1.2.0) shows that GRACE significantly outperforms state-of-the-art coverage-based fault localization: GRACE localizes 195 bugs within Top-1 whereas the best compared technique can at most localize 166 bugs within Top-1. We further investigate the impact of each GRACE component and find that they all positively contribute to GRACE. In addition, our results also demonstrate that GRACE has learnt essential features from coverage, which are complementary to various information used in existing learning-based fault localization. Finally, we evaluate GRACE in the cross-project prediction scenario on extra 226 bugs from Defects4J (V2.0.0), and find that GRACE consistently outperforms state-of-the-art coverage-based techniques.

Serverless computing is an emerging paradigm for cloud computing, gaining traction in a wide range of applications such as video processing and machine learning. This new paradigm allows developers to focus on the development of the logic of serverless computing based applications (abbreviated as serverless-based applications) in the granularity of function, thereby freeing developers from tedious and error-prone infrastructure management. Meanwhile, it also introduces new challenges on the design, implementation, and deployment of serverless-based applications, and current serverless computing platforms are far away from satisfactory. However, to the best of our knowledge, these challenges have not been well studied. To fill this knowledge gap, this paper presents the first comprehensive study on understanding the challenges in developing serverless-based applications from the developers’ perspective. We mine and analyze 22,731 relevant questions from Stack Overflow (a popular Q&A website for developers), and show the increasing popularity trend and the high difficulty level of serverless computing for developers. Through manual inspection of 619 sampled questions, we construct a taxonomy of challenges that developers encounter, and report a series of findings and actionable implications. Stakeholders including application developers, researchers, and cloud providers can leverage these findings and implications to better understand and further explore the serverless computing paradigm.

A large body of research efforts have been dedicated to automated software debugging, including both automated fault localization and program repair. However, existing fault localization techniques have limited effectiveness on real-world software systems while even the most advanced program repair techniques can only fix a small ratio of real-world bugs. Although fault localization and program repair are inherently connected, their only existing connection in the literature is that program repair techniques usually use off-the-shelf fault localization techniques (e.g., Ochiai) to determine the potential candidate statements/elements for patching. In this work, we propose the unified debugging approach to unify the two areas in the other direction for the first time, i.e., can program repair in turn help with fault localization? In this way, we not only open a new dimension for more powerful fault localization, but also extend the application scope of program repair to all possible bugs (not only the bugs that can be directly automatically fixed). We have designed ProFL to leverage patch-execution results (from program repair) as the feedback information for fault localization. The experimental results on the widely used Defects4J benchmark show that the basic ProFL can already at least localize 37.61% more bugs within Top-1 than state-of-the-art spectrum and mutation based fault localization. Furthermore, ProFL can boost state-of-the-art fault localization via both unsupervised and supervised learning. Meanwhile, we have demonstrated ProFL's effectiveness under different settings and through a case study within Alipay, a popular online payment system with over 1 billion global users.

Automated debugging techniques, including fault localization and program repair, have been studied for over a decade. However, the only existing connection between fault localization and program repair is that fault localization computes the potential buggy elements for program repair to patch. Recently, a pioneering work, ProFL, explored the idea of unified debugging to unify fault localization and program repair in the other direction for the first time to boost both areas. More specifically, ProFL utilizes the patch execution results from one state-of-the-art repair system, PraPR, to help improve state-of-the-art fault localization. In this way, ProFL not only improves fault localization for manual repair, but also extends the application scope of automated repair to all possible bugs (not only the small ratio of bugs that can be automaticallyfi xed). However, ProFL only considers one APR system (i.e., PraPR), and it is not clear how other existing APR systems based on different designs contribute to unified debugging. In this work, we perform an extensive study of the unified-debugging approach on 16 state-of-the-art program repair systems for the first time. Our experimental results on the widely studied Defects4J benchmark suite reveal various practical guidelines for unified debugging, such as (1) nearly all the studied 16 repair systems can positively contribute to unified debugging despite their varying repairing capabilities, (2) repair systems targeting multi-edit patches can bring extraneous noise into unified debugging, (3) repair systems with more executed/plausible patches tend to perform better for unified debugging, and (4) unified debugging effectiveness does not rely on the availability of correct patches in automated repair. Based on our results, we further propose an advanced unified debugging technique, UniDebug++, which can localize over 20% more bugs within Top-1 positions than state-of-the-art unified debugging technique, ProFL.

Regression testing is widely recognized as an important but time-consuming process. To alleviate this cost issue, test selection, reduction, and prioritization have been widely studied, and they share the commonality that they improve regression testing by optimizing the execution of the whole test suite. In this paper, we attempt to accelerate regression testing from a totally new perspective, i.e., skipping some execution of a new program by reusing program states of an old program. Following this intuition, we propose a state-reuse based acceleration approach SRRTA, consisting of two components: state storage and loading. With the former, SRRTA collects some program states during the execution of an old version through three heuristic-based storage strategies; with the latter, SRRTA loads the stored program states with efficiency optimization strategies. Through the preliminary study on commons-math, SRRTA reduces 82.7% of the regression testing time.

Build systems are essential for modern software maintenance and development, while build failures occur frequently across software systems, inducing non-negligible costs in development activities. Build failure resolution is a challenging problem and multiple studies have demonstrated that developers spend non-trivial time in resolving encountered build failures; to relieve manual efforts, automated resolution techniques are emerging recently, which are promising but still limitedly effective. Understanding how build failures are resolved in practice can provide guidelines for both developers and researchers on build issue resolution. Therefore, this work presents a comprehensive study of fix patterns in practical build failures. Specifically, we study 1,080 build issues of three popular build systems Maven, Ant, and Gradle from Stack Overflow, construct a fine-granularity taxonomy of 50 categories regarding to the failure symptoms, and summarize the fix patterns for different failure types. Our key findings reveal that build issues stretch over a wide spectrum of symptoms; 67.96% of the build issues are fixed by modifying the build script code related to plugins and dependencies; and there are 20 symptom categories, more than half of whose build issues can be fixed by specific patterns. Furthermore, we also address the challenges in applying non-intuitive or simplistic fix patterns for developers.

Build systems are essential for modern software development and maintenance since they are widely used to transform source code artifacts into executable software. Previous work shows that build systems break frequently during software evolution. Therefore, automated build-fixing techniques are in huge demand. In this paper we target a mainstream build system, Gradle, which has become the most widely used build system for Java projects in the open-source community (e.g., GitHub). HireBuild, state-of-the-art build-fixing tool for Gradle, has been recently proposed to fix Gradle build failures via mining the history of prior fixes. Although HireBuild has been shown to be effective for fixing real-world Gradle build failures, it was evaluated on only a limited set of build failures, and largely depends on the quality/availability of historical fix information. To investigate the efficacy and limitations of the history-driven build fix, we first construct a new and large build failure dataset from Top-1000 GitHub projects. Then, we evaluate HireBuild on the extended dataset both quantitatively and qualitatively. Inspired by the findings of the study, we propose a simplistic new technique that generates potential patches via searching from the present project under test and external resources rather than the historical fix information. According to our experimental results, the simplistic approach based on present information successfully fixes 2X more reproducible build failures than the state-of-art HireBuild based on historical fix information. Furthermore, our results also reveal various findings/guidelines for future advanced build failure fixing.

Test prioritization aims to detect regression faults faster via reordering test executions, and a large number of test prioritization techniques have been proposed accordingly. However, test prioritization effectiveness is usually measured in terms of the average percentage of faults detected concerned with the number of test executions, rather than the actual regression testing time, making it unclear which technique is optimal in actual regression testing time. To answer this question, this paper first conducts an empirical study to investigate the actual regression testing time of various prioritization techniques. The results reveal a number of practical guidelines. In particular, no prioritization technique can always perform optimal in practice.

In recent years, researchers have intensively investigated various topics in test prioritization, which aims to re-order tests to increase the rate of fault detection during regression testing. While the main research focus in test prioritization is on proposing novel prioritization techniques and evaluating on more and larger subject systems, little effort has been put on investigating the threats to validity in existing work on test prioritization. One main threat to validity is that existing work mainly evaluates prioritization techniques based on simple artificial changes on the source code and tests. For example, the changes in the source code usually include only seeded program faults, whereas the test suite is usually not augmented at all. On the contrary, in real-world software development, software systems usually undergo various changes on the source code and test suite augmentation. Therefore, it is not clear whether the conclusions drawn by existing work in test prioritization from the artificial changes are still valid for real-world software evolution. In this paper, we present the first empirical study to investigate this important threat to validity in test prioritization. We reimplemented 24 variant techniques of both the traditional and time-aware test prioritization, and investigated the impacts of software evolution on those techniques based on the version history of 8 real-world Java programs from GitHub. The results show that for both traditional and time-aware test prioritization, test suite augmentation significantly hampers their effectiveness, whereas source code changes alone do not influence their effectiveness much.

In software testing, it is very hard to achieve high coverage with the program under test, leaving many behaviors unexplored. To alleviate this problem, various automated test generation and augmentation approaches have been proposed, among which symbolic execution and search-based techniques are the most competitive, while each has key challenges to be solved. Different from prior work, we present a new methodology for regression testing --Isomorphic Regression Testing,which explores the behaviors of the program under test by creating its variants (i.e., modified programs) instead of generating tests. In this paper, we make the first implementation of isomorphic regression testing through an approach named ISON, which creates program variants by negating branch conditions. The results show that ISON is able to additionally execute 5.3% to 80.0% branches that are originally uncovered. Furthermore, ISON also detects a number of faults not detected by a popular automated test generation tool (i.e., EvoSuite) under the scenario of regression testing.

During software evolution, to assure the software quality, test cases for an early version tend to be reused by its latter versions. As a large number of test cases may aggregate during software evolution, it becomes necessary to schedule the execution order of test cases so that the faults in the latter version may be detected as early as possible, which is test-case prioritization in software evolution. In this paper, we proposed a novel test-case prioritization approach for software evolution, which first uses mutation faults on the difference between the early version and the latter version to simulate real faults occurred in software evolution, and then schedules the execution order of test cases based on their fault-detection capability, which is defined based on mutation faults. In particular, we present two models on calculating fault-detection capability, which are statistics-based model and probability-based model. Moreover, we conducted an experimental study and found that our approach with the statistics-based model outperforms our approach with the probability-based model and the total statement coverage-based approach, and slightly outperforms the additional statement-coverage based approach in many cases. Furthermore, compared with the total or additional statement coverage-based approach, our approach with either the statistics-based model or the probability-based model tends to be stably effective when the difference on the source code between the early version and the latter version is non-trivial.