DROPS

Volume

LIPIcs, Volume 194

35th European Conference on Object-Oriented Programming (ECOOP 2021)

ECOOP 2021, July 11-17, 2021, Aarhus, Denmark (Virtual Conference)

Editors: Anders Møller and Manu Sridharan

Document

DOI: 10.4230/LIPIcs.ECOOP.2024.8

Understanding Concurrency Bugs in Real-World Programs with Kotlin Coroutines

Authors: Bob Brockbernd, Nikita Koval, Arie van Deursen, and Burcu Kulahcioglu Ozkan

Published in: LIPIcs, Volume 313, 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract

Kotlin language has recently become prominent for developing both Android and server-side applications. These programs are typically designed to be fast and responsive, with asynchrony and concurrency at their core. To enable developers to write asynchronous and concurrent code safely and concisely, Kotlin provides built-in coroutines support. However, developers unfamiliar with the coroutines concept may write programs with subtle concurrency bugs and face unexpected program behaviors. Besides the traditional concurrency bug patterns, such as data races and deadlocks, these bugs may exhibit patterns related to the coroutine semantics. Understanding these coroutine-specific bug patterns in real-world Kotlin applications is essential in avoiding common mistakes and writing correct programs. In this paper, we present the first study of real-world concurrency bugs related to Kotlin coroutines. We examined 55 concurrency bug cases selected from 7 popular open-source repositories that use Kotlin coroutines, including IntelliJ IDEA, Firefox, and Ktor, and analyzed their bug characteristics and root causes. We identified common bug patterns related to asynchrony and Kotlin’s coroutine semantics, presenting them with their root causes, misconceptions that led to the bugs, and strategies for their automated detection. Overall, this study provides insight into programming with Kotlin coroutines concurrency and its pitfalls, aiming to shed light on common bug patterns and foster further research and development of concurrency analysis tools for Kotlin programs.

Cite as

Bob Brockbernd, Nikita Koval, Arie van Deursen, and Burcu Kulahcioglu Ozkan. Understanding Concurrency Bugs in Real-World Programs with Kotlin Coroutines. In 38th European Conference on Object-Oriented Programming (ECOOP 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 313, pp. 8:1-8:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{brockbernd_et_al:LIPIcs.ECOOP.2024.8,
  author =	{Brockbernd, Bob and Koval, Nikita and van Deursen, Arie and Ozkan, Burcu Kulahcioglu},
  title =	{{Understanding Concurrency Bugs in Real-World Programs with Kotlin Coroutines}},
  booktitle =	{38th European Conference on Object-Oriented Programming (ECOOP 2024)},
  pages =	{8:1--8:20},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-341-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{313},
  editor =	{Aldrich, Jonathan and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2024.8},
  URN =		{urn:nbn:de:0030-drops-208579},
  doi =		{10.4230/LIPIcs.ECOOP.2024.8},
  annote =	{Keywords: Kotlin, coroutines, concurrency, asynchrony, software bugs}
}

Document

DOI: 10.4230/LIPIcs.ECOOP.2024.10

Indirection-Bounded Call Graph Analysis

Authors: Madhurima Chakraborty, Aakash Gnanakumar, Manu Sridharan, and Anders Møller

Published in: LIPIcs, Volume 313, 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract

Call graphs play a crucial role in analyzing the structure and behavior of programs. For JavaScript and other dynamically typed programming languages, static call graph analysis relies on approximating the possible flow of functions and objects, and producing usable call graphs for large, real-world programs remains challenging. In this paper, we propose a simple but effective technique that addresses performance issues encountered in call graph generation. We observe via a dynamic analysis that typical JavaScript program code exhibits small levels of indirection of object pointers and higher-order functions. We demonstrate that a widely used analysis algorithm, wave propagation, closely follows the levels of indirections, so that call edges discovered early are more likely to be true positives. By bounding the number of indirections covered by this analysis, in many cases it can find most true-positive call edges in less time. We also show that indirection-bounded analysis can similarly be incorporated into the field-based call graph analysis algorithm ACG. We have experimentally evaluated the modified wave propagation algorithm on 25 large Node.js-based JavaScript programs. Indirection-bounded analysis on average yields close to a 2X speed-up with only 5% reduction in recall and almost identical precision relative to the baseline analysis, using dynamically generated call graphs for the recall and precision measurements. To demonstrate the robustness of the approach, we also evaluated the modified ACG algorithm on 10 web-based and 4 mobile-based medium sized benchmarks, with similar results.

Cite as

Madhurima Chakraborty, Aakash Gnanakumar, Manu Sridharan, and Anders Møller. Indirection-Bounded Call Graph Analysis. In 38th European Conference on Object-Oriented Programming (ECOOP 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 313, pp. 10:1-10:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{chakraborty_et_al:LIPIcs.ECOOP.2024.10,
  author =	{Chakraborty, Madhurima and Gnanakumar, Aakash and Sridharan, Manu and M{\o}ller, Anders},
  title =	{{Indirection-Bounded Call Graph Analysis}},
  booktitle =	{38th European Conference on Object-Oriented Programming (ECOOP 2024)},
  pages =	{10:1--10:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-341-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{313},
  editor =	{Aldrich, Jonathan and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2024.10},
  URN =		{urn:nbn:de:0030-drops-208599},
  doi =		{10.4230/LIPIcs.ECOOP.2024.10},
  annote =	{Keywords: JavaScript, call graphs, points-to analysis}
}

Document

DOI: 10.4230/LIPIcs.ECOOP.2024.18

A CFL-Reachability Formulation of Callsite-Sensitive Pointer Analysis with Built-In On-The-Fly Call Graph Construction

Authors: Dongjie He, Jingbo Lu, and Jingling Xue

Published in: LIPIcs, Volume 313, 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract

In object-oriented languages, the traditional CFL-reachability formulation for k-callsite-sensitive pointer analysis (kCFA) focuses on modeling field accesses and calling contexts, but it relies on a separate algorithm for call graph construction. This division can result in a loss of precision in kCFA, a problem that persists even when using the most precise call graphs, whether pre-constructed or generated on the fly. Moreover, pre-analyses based on this framework aiming to improve the efficiency of kCFA may inadvertently reduce its precision, due to the framework’s lack of native call graph construction, essential for precise analysis. Addressing this gap, this paper introduces a novel CFL-reachability formulation of kCFA for Java, uniquely integrating on-the-fly call graph construction. This advancement not only addresses the precision loss inherent in the traditional CFL-reachability-based approach but also enhances its overall applicability. In a significant secondary contribution, we present the first precision-preserving pre-analysis to accelerate kCFA. This pre-analysis leverages selective context sensitivity to improve the efficiency of kCFA without sacrificing its precision. Collectively, these contributions represent a substantial step forward in pointer analysis, offering both theoretical and practical advancements that could benefit future developments in the field.

Cite as

Dongjie He, Jingbo Lu, and Jingling Xue. A CFL-Reachability Formulation of Callsite-Sensitive Pointer Analysis with Built-In On-The-Fly Call Graph Construction. In 38th European Conference on Object-Oriented Programming (ECOOP 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 313, pp. 18:1-18:29, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{he_et_al:LIPIcs.ECOOP.2024.18,
  author =	{He, Dongjie and Lu, Jingbo and Xue, Jingling},
  title =	{{A CFL-Reachability Formulation of Callsite-Sensitive Pointer Analysis with Built-In On-The-Fly Call Graph Construction}},
  booktitle =	{38th European Conference on Object-Oriented Programming (ECOOP 2024)},
  pages =	{18:1--18:29},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-341-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{313},
  editor =	{Aldrich, Jonathan and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2024.18},
  URN =		{urn:nbn:de:0030-drops-208674},
  doi =		{10.4230/LIPIcs.ECOOP.2024.18},
  annote =	{Keywords: Pointer Analysis, CFL Reachability, Call Graph Construction}
}

Document

DOI: 10.4230/LIPIcs.ECOOP.2024.19

Fearless Asynchronous Communications with Timed Multiparty Session Protocols

Authors: Ping Hou, Nicolas Lagaillardie, and Nobuko Yoshida

Published in: LIPIcs, Volume 313, 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract

Session types using affinity and exception handling mechanisms have been developed to ensure the communication safety of protocols implemented in concurrent and distributed programming languages. Nevertheless, current affine session types are inadequate for specifying real-world asynchronous protocols, as they are usually imposed by time constraints which enable timeout exceptions to prevent indefinite blocking while awaiting valid messages. This paper proposes the first formal integration of affinity, time constraints, timeouts, and time-failure handling based on multiparty session types for supporting reliability in asynchronous distributed systems. With this theory, we statically guarantee that asynchronous timed communication is deadlock-free, communication safe, while being fearless - never hindered by timeout errors or abrupt terminations. To implement our theory, we introduce MultiCrusty^T, a Rust toolchain designed to facilitate the implementation of safe affine timed protocols. MultiCrusty^T leverages generic types and the time library to handle timed communications, integrated with optional types for affinity. We evaluate MultiCrusty^T by extending diverse examples from the literature to incorporate time and timeouts. We also showcase the correctness by construction of our approach by implementing various real-world use cases, including protocols from the Internet of Remote Things domain and real-time systems.

Cite as

Ping Hou, Nicolas Lagaillardie, and Nobuko Yoshida. Fearless Asynchronous Communications with Timed Multiparty Session Protocols. In 38th European Conference on Object-Oriented Programming (ECOOP 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 313, pp. 19:1-19:30, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{hou_et_al:LIPIcs.ECOOP.2024.19,
  author =	{Hou, Ping and Lagaillardie, Nicolas and Yoshida, Nobuko},
  title =	{{Fearless Asynchronous Communications with Timed Multiparty Session Protocols}},
  booktitle =	{38th European Conference on Object-Oriented Programming (ECOOP 2024)},
  pages =	{19:1--19:30},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-341-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{313},
  editor =	{Aldrich, Jonathan and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2024.19},
  URN =		{urn:nbn:de:0030-drops-208681},
  doi =		{10.4230/LIPIcs.ECOOP.2024.19},
  annote =	{Keywords: Session Types, Concurrency, Time Failure Handling, Affinity, Timeout, Rust}
}

Document

DOI: 10.4230/LIPIcs.ECOOP.2024.21

Learning Gradual Typing Performance

Authors: Mohammad Wahiduzzaman Khan, Sheng Chen, and Yi He

Published in: LIPIcs, Volume 313, 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract

Gradual typing has emerged as a promising typing discipline for reconciling static and dynamic typing, which have respective strengths and shortcomings. Thanks to its promises, gradual typing has gained tremendous momentum in both industry and academia. A main challenge in gradual typing is that, however, the performance of its programs can often be unpredictable, and adding or removing the type of a a single parameter may lead to wild performance swings. Many approaches have been proposed to optimize gradual typing performance, but little work has been done to aid the understanding of the performance landscape of gradual typing and navigating the migration process (which adds type annotations to make programs more static) to avert performance slowdowns. Motivated by this situation, this work develops a machine-learning-based approach to predict the performance of each possible way of adding type annotations to a program. On top of that, many supports for program migrations could be developed, such as finding the most performant neighbor of any given configuration. Our approach gauges runtime overheads of dynamic type checks inserted by gradual typing and uses that information to train a machine learning model, which is used to predict the running time of gradual programs. We have evaluated our approach on 12 Python benchmarks for both guarded and transient semantics. For guarded semantics, our evaluation results indicate that with only 40 training instances generated from each benchmark, the predicted times for all other instances differ on average by 4% from the measured times. For transient semantics, the time difference ratio is higher but the time difference is often within 0.1 seconds.

Cite as

Mohammad Wahiduzzaman Khan, Sheng Chen, and Yi He. Learning Gradual Typing Performance. In 38th European Conference on Object-Oriented Programming (ECOOP 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 313, pp. 21:1-21:27, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{khan_et_al:LIPIcs.ECOOP.2024.21,
  author =	{Khan, Mohammad Wahiduzzaman and Chen, Sheng and He, Yi},
  title =	{{Learning Gradual Typing Performance}},
  booktitle =	{38th European Conference on Object-Oriented Programming (ECOOP 2024)},
  pages =	{21:1--21:27},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-341-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{313},
  editor =	{Aldrich, Jonathan and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2024.21},
  URN =		{urn:nbn:de:0030-drops-208706},
  doi =		{10.4230/LIPIcs.ECOOP.2024.21},
  annote =	{Keywords: Gradual typing performance, type migration, performance prediction, machine learning}
}

Document

DOI: 10.4230/LIPIcs.ECOOP.2024.36

Scaling Interprocedural Static Data-Flow Analysis to Large C/C++ Applications: An Experience Report

Authors: Fabian Schiebel, Florian Sattler, Philipp Dominik Schubert, Sven Apel, and Eric Bodden

Published in: LIPIcs, Volume 313, 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract

Interprocedural data-flow analysis is important for computing precise information on whole programs. In theory, the popular algorithmic framework interprocedural distributive environments (IDE) provides a tool to solve distributive interprocedural data-flow problems efficiently. Yet, unfortunately, available state-of-the-art implementations of the IDE framework start to run into scalability issues for programs with several thousands of lines of code, depending on the static analysis domain. Since the IDE framework is a basic building block for many static program analyses, this presents a serious limitation. In this paper, we report on our experience with making the IDE algorithm scale to C/C++ applications with up to 500 000 lines of code. We analyze the IDE algorithm and its state-of-the-art implementations to identify their weaknesses related to scalability at both a conceptual and implementation level. Based on this analysis, we propose several optimizations to overcome these weaknesses, aiming at a sweet spot between reducing running time and memory consumption. As a result, we provide an improved IDE solver that implements our optimizations within the PhASAR static analysis framework. Our evaluation on real-world C/C++ applications shows that applying the optimizations speeds up the analysis on average by up to 7×, while also reducing memory consumption by 7× on average as well. For the first time, these optimizations allow us to analyze programs with several hundreds of thousands of lines of LLVM-IR code in reasonable time and space.

Cite as

Fabian Schiebel, Florian Sattler, Philipp Dominik Schubert, Sven Apel, and Eric Bodden. Scaling Interprocedural Static Data-Flow Analysis to Large C/C++ Applications: An Experience Report. In 38th European Conference on Object-Oriented Programming (ECOOP 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 313, pp. 36:1-36:28, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{schiebel_et_al:LIPIcs.ECOOP.2024.36,
  author =	{Schiebel, Fabian and Sattler, Florian and Schubert, Philipp Dominik and Apel, Sven and Bodden, Eric},
  title =	{{Scaling Interprocedural Static Data-Flow Analysis to Large C/C++ Applications: An Experience Report}},
  booktitle =	{38th European Conference on Object-Oriented Programming (ECOOP 2024)},
  pages =	{36:1--36:28},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-341-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{313},
  editor =	{Aldrich, Jonathan and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2024.36},
  URN =		{urn:nbn:de:0030-drops-208859},
  doi =		{10.4230/LIPIcs.ECOOP.2024.36},
  annote =	{Keywords: Interprocedural data-flow analysis, IDE, LLVM, C/C++}
}

Document

DOI: 10.4230/LIPIcs.ECOOP.2024.47

Defining Name Accessibility Using Scope Graphs

Authors: Aron Zwaan and Casper Bach Poulsen

Published in: LIPIcs, Volume 313, 38th European Conference on Object-Oriented Programming (ECOOP 2024)

Abstract

Many programming languages allow programmers to regulate accessibility; i.e., annotating a declaration with keywords such as export and private to indicate where it can be accessed. Despite the importance of name accessibility for, e.g., compilers, editor auto-completion and tooling, and automated refactorings, few existing type systems provide a formal account of name accessibility. We present a declarative, executable, and language-parametric model for name accessibility, which provides a formal specification of name accessibility in Java, C#, C++, Rust, and Eiffel. We achieve this by defining name accessibility as a predicate on resolution paths through scope graphs. Since scope graphs are a language-independent model of name resolution, our model provides a uniform approach to defining different accessibility policies for different languages. Our model is implemented in Statix, a logic language for executable type system specification using scope graphs. We evaluate its correctness on a test suite that compares it with the C#, Java, and Rust compilers, and show we can synthesize access modifiers in programs with holes accurately.

Cite as

Aron Zwaan and Casper Bach Poulsen. Defining Name Accessibility Using Scope Graphs. In 38th European Conference on Object-Oriented Programming (ECOOP 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 313, pp. 47:1-47:29, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{zwaan_et_al:LIPIcs.ECOOP.2024.47,
  author =	{Zwaan, Aron and Bach Poulsen, Casper},
  title =	{{Defining Name Accessibility Using Scope Graphs}},
  booktitle =	{38th European Conference on Object-Oriented Programming (ECOOP 2024)},
  pages =	{47:1--47:29},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-341-6},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{313},
  editor =	{Aldrich, Jonathan and Salvaneschi, Guido},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2024.47},
  URN =		{urn:nbn:de:0030-drops-208961},
  doi =		{10.4230/LIPIcs.ECOOP.2024.47},
  annote =	{Keywords: access modifier, visibility, scope graph, name resolution}
}

Document

DOI: 10.4230/LIPIcs.SAT.2024.15

Antichain with SAT and Tries

Authors: Lukáš Holík and Pavol Vargovčík

Published in: LIPIcs, Volume 305, 27th International Conference on Theory and Applications of Satisfiability Testing (SAT 2024)

Abstract

We introduce a SAT-enabled version of an antichain algorithm for checking language emptiness of alternating finite automata (AFA) with complex transition relations encoded as compact logical formulae. The SAT solver is used to compute predecessors of AFA configurations, and at the same time, to evaluate the subsumption of newly found configurations in the antichain of the previously found ones. The algorithm could be naively implemented by an incremental SAT solver where the growing antichain is represented by adding new clauses. To make it efficient, we 1) force the SAT solver to prioritize largest/subsumption-strongest predecessors (so that weaker configurations are not even generated), and 2) store the antichain clauses in a special variant of a trie that allows fast subsumption testing. The experimental results suggest that the resulting emptiness checker is very efficient compared to the state of the art and that our techniques improve the performance of the SAT solver.

Cite as

Lukáš Holík and Pavol Vargovčík. Antichain with SAT and Tries. In 27th International Conference on Theory and Applications of Satisfiability Testing (SAT 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 305, pp. 15:1-15:24, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{holik_et_al:LIPIcs.SAT.2024.15,
  author =	{Hol{\'\i}k, Luk\'{a}\v{s} and Vargov\v{c}{\'\i}k, Pavol},
  title =	{{Antichain with SAT and Tries}},
  booktitle =	{27th International Conference on Theory and Applications of Satisfiability Testing (SAT 2024)},
  pages =	{15:1--15:24},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-334-8},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{305},
  editor =	{Chakraborty, Supratik and Jiang, Jie-Hong Roland},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SAT.2024.15},
  URN =		{urn:nbn:de:0030-drops-205372},
  doi =		{10.4230/LIPIcs.SAT.2024.15},
  annote =	{Keywords: SAT, Trie, Antichain, Alternating automata, Subset query}
}

Document

DOI: 10.4230/LIPIcs.ECOOP.2022.5

How to Take the Inverse of a Type

Authors: Danielle Marshall and Dominic Orchard

Published in: LIPIcs, Volume 222, 36th European Conference on Object-Oriented Programming (ECOOP 2022)

Abstract

In functional programming, regular types are a subset of algebraic data types formed from products and sums with their respective units. One can view regular types as forming a commutative semiring but where the usual axioms are isomorphisms rather than equalities. In this pearl, we show that regular types in a linear setting permit a useful notion of multiplicative inverse, allowing us to "divide" one type by another. Our adventure begins with an exploration of the properties and applications of this construction, visiting various topics from the literature including program calculation, Laurent polynomials, and derivatives of data types. Examples are given throughout using Haskell’s linear types extension to demonstrate the ideas. We then step through the looking glass to discover what might be possible in richer settings; the functional language Granule offers linear functions that incorporate local side effects, which allow us to demonstrate further algebraic structure. Lastly, we discuss whether dualities in linear logic might permit the related notion of an additive inverse.

Cite as

Danielle Marshall and Dominic Orchard. How to Take the Inverse of a Type. In 36th European Conference on Object-Oriented Programming (ECOOP 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 222, pp. 5:1-5:27, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@InProceedings{marshall_et_al:LIPIcs.ECOOP.2022.5,
  author =	{Marshall, Danielle and Orchard, Dominic},
  title =	{{How to Take the Inverse of a Type}},
  booktitle =	{36th European Conference on Object-Oriented Programming (ECOOP 2022)},
  pages =	{5:1--5:27},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-225-9},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{222},
  editor =	{Ali, Karim and Vitek, Jan},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2022.5},
  URN =		{urn:nbn:de:0030-drops-162339},
  doi =		{10.4230/LIPIcs.ECOOP.2022.5},
  annote =	{Keywords: linear types, regular types, algebra of programming, derivatives}
}

Document

Complete Volume

DOI: 10.4230/LIPIcs.ECOOP.2021

LIPIcs, Volume 194, ECOOP 2021, Complete Volume

Authors: Anders Møller and Manu Sridharan

Published in: LIPIcs, Volume 194, 35th European Conference on Object-Oriented Programming (ECOOP 2021)

Abstract

LIPIcs, Volume 194, ECOOP 2021, Complete Volume

Cite as

35th European Conference on Object-Oriented Programming (ECOOP 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 194, pp. 1-628, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

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@Proceedings{mller_et_al:LIPIcs.ECOOP.2021,
  title =	{{LIPIcs, Volume 194, ECOOP 2021, Complete Volume}},
  booktitle =	{35th European Conference on Object-Oriented Programming (ECOOP 2021)},
  pages =	{1--628},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-190-0},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{194},
  editor =	{M{\o}ller, Anders and Sridharan, Manu},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2021},
  URN =		{urn:nbn:de:0030-drops-140422},
  doi =		{10.4230/LIPIcs.ECOOP.2021},
  annote =	{Keywords: LIPIcs, Volume 194, ECOOP 2021, Complete Volume}
}

Document

Front Matter

DOI: 10.4230/LIPIcs.ECOOP.2021.0

Front Matter, Table of Contents, Preface, Conference Organization

Authors: Anders Møller and Manu Sridharan

Published in: LIPIcs, Volume 194, 35th European Conference on Object-Oriented Programming (ECOOP 2021)

Abstract

Front Matter, Table of Contents, Preface, Conference Organization

Cite as

35th European Conference on Object-Oriented Programming (ECOOP 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 194, pp. 0:i-0:xxiv, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

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@InProceedings{mller_et_al:LIPIcs.ECOOP.2021.0,
  author =	{M{\o}ller, Anders and Sridharan, Manu},
  title =	{{Front Matter, Table of Contents, Preface, Conference Organization}},
  booktitle =	{35th European Conference on Object-Oriented Programming (ECOOP 2021)},
  pages =	{0:i--0:xxiv},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-190-0},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{194},
  editor =	{M{\o}ller, Anders and Sridharan, Manu},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2021.0},
  URN =		{urn:nbn:de:0030-drops-140438},
  doi =		{10.4230/LIPIcs.ECOOP.2021.0},
  annote =	{Keywords: Front Matter, Table of Contents, Preface, Conference Organization}
}

Document

DOI: 10.4230/LIPIcs.ECOOP.2020.16

Value Partitioning: A Lightweight Approach to Relational Static Analysis for JavaScript

Authors: Benjamin Barslev Nielsen and Anders Møller

Published in: LIPIcs, Volume 166, 34th European Conference on Object-Oriented Programming (ECOOP 2020)

Abstract

In static analysis of modern JavaScript libraries, relational analysis at key locations is critical to provide sound and useful results. Prior work addresses this challenge by the use of various forms of trace partitioning and syntactic patterns, which is fragile and does not scale well, or by incorporating complex backwards analysis. In this paper, we propose a new lightweight variant of trace partitioning named value partitioning that refines individual abstract values instead of entire abstract states. We describe how this approach can effectively capture important relational properties involving dynamic property accesses, functions with free variables, and predicate functions. Furthermore, we extend an existing JavaScript analyzer with value partitioning and demonstrate experimentally that it is a simple, precise, and efficient alternative to the existing approaches for analyzing widely used JavaScript libraries.

Cite as

Benjamin Barslev Nielsen and Anders Møller. Value Partitioning: A Lightweight Approach to Relational Static Analysis for JavaScript. In 34th European Conference on Object-Oriented Programming (ECOOP 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 166, pp. 16:1-16:28, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

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@InProceedings{nielsen_et_al:LIPIcs.ECOOP.2020.16,
  author =	{Nielsen, Benjamin Barslev and M{\o}ller, Anders},
  title =	{{Value Partitioning: A Lightweight Approach to Relational Static Analysis for JavaScript}},
  booktitle =	{34th European Conference on Object-Oriented Programming (ECOOP 2020)},
  pages =	{16:1--16:28},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-154-2},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{166},
  editor =	{Hirschfeld, Robert and Pape, Tobias},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2020.16},
  URN =		{urn:nbn:de:0030-drops-131731},
  doi =		{10.4230/LIPIcs.ECOOP.2020.16},
  annote =	{Keywords: JavaScript, dataflow analysis, abstract interpretation}
}

Document

DOI: 10.4230/LIPIcs.ECOOP.2018.7

Type Regression Testing to Detect Breaking Changes in Node.js Libraries

Authors: Gianluca Mezzetti, Anders Møller, and Martin Toldam Torp

Published in: LIPIcs, Volume 109, 32nd European Conference on Object-Oriented Programming (ECOOP 2018)

Abstract

The npm repository contains JavaScript libraries that are used by millions of software developers. Its semantic versioning system relies on the ability to distinguish between breaking and non-breaking changes when libraries are updated. However, the dynamic nature of JavaScript often causes unintended breaking changes to be detected too late, which undermines the robustness of the applications. We present a novel technique, type regression testing, to automatically determine whether an update of a library implementation affects the types of its public interface, according to how the library is being used by other npm packages. By leveraging available test suites of clients, type regression testing uses a dynamic analysis to learn models of the library interface. Comparing the models before and after an update effectively amplifies the existing tests by revealing changes that may affect the clients. Experimental results on 12 widely used libraries show that the technique can identify type-related breaking changes with high accuracy. It fully automatically classifies at least 90% of the updates correctly as either major or as minor or patch, and it detects 26 breaking changes among the minor and patch updates.

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Gianluca Mezzetti, Anders Møller, and Martin Toldam Torp. Type Regression Testing to Detect Breaking Changes in Node.js Libraries. In 32nd European Conference on Object-Oriented Programming (ECOOP 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 109, pp. 7:1-7:24, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)

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@InProceedings{mezzetti_et_al:LIPIcs.ECOOP.2018.7,
  author =	{Mezzetti, Gianluca and M{\o}ller, Anders and Torp, Martin Toldam},
  title =	{{Type Regression Testing to Detect Breaking Changes in Node.js Libraries}},
  booktitle =	{32nd European Conference on Object-Oriented Programming (ECOOP 2018)},
  pages =	{7:1--7:24},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-079-8},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{109},
  editor =	{Millstein, Todd},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2018.7},
  URN =		{urn:nbn:de:0030-drops-92128},
  doi =		{10.4230/LIPIcs.ECOOP.2018.7},
  annote =	{Keywords: JavaScript, semantic versioning, dynamic analysis}
}

Document

DOI: 10.4230/DARTS.4.3.8

Type Regression Testing to Detect Breaking Changes in Node.js Libraries (Artifact)

Authors: Gianluca Mezzetti, Anders Møller, and Martin Toldam Torp

Published in: DARTS, Volume 4, Issue 3, Special Issue of the 32nd European Conference on Object-Oriented Programming (ECOOP 2018)

Abstract

This artifact provides an implementation of a novel technique, type regression testing, to automatically determine whether an update of a npm library implementation affects the types of its public interface, according to how the library is being used by other npm packages. Type regression testing is implemented in the tool NoRegrets. A run of NoRegrets is parameterized with a pre-update and post-update version of the library, and it consists of three fully automatic phases. First, NoRegrets fetches a list of clients that depend upon the pre-update library, and that have a test suite that succeeds on the pre-update version. Second, NoRegrets uses an ECMAScript 6 proxy instrumentation to generate the API model of both the pre-update and post-update libraries, based on observations of how the client test suites interact with the library. Third, the two models are compared, and inconsistencies are reported as type regressions. This artifact contains the source code and an installation of NoRegrets, with a guide for how to use the tool and reproduce the experimental results presented in the paper.

Cite as

Gianluca Mezzetti, Anders Møller, and Martin Toldam Torp. Type Regression Testing to Detect Breaking Changes in Node.js Libraries (Artifact). In Special Issue of the 32nd European Conference on Object-Oriented Programming (ECOOP 2018). Dagstuhl Artifacts Series (DARTS), Volume 4, Issue 3, pp. 8:1-8:2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)

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@Article{mezzetti_et_al:DARTS.4.3.8,
  author =	{Mezzetti, Gianluca and M{\o}ller, Anders and Torp, Martin Toldam},
  title =	{{Type Regression Testing to Detect Breaking Changes in Node.js Libraries (Artifact)}},
  pages =	{8:1--8:2},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2018},
  volume =	{4},
  number =	{3},
  editor =	{Mezzetti, Gianluca and M{\o}ller, Anders and Torp, Martin Toldam},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.4.3.8},
  URN =		{urn:nbn:de:0030-drops-92394},
  doi =		{10.4230/DARTS.4.3.8},
  annote =	{Keywords: JavaScript, semantic versioning, dynamic analysis}
}

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