Technical debt is a metaphor, coined by ward cunningham, that frames how to think about dealing with this cruft, thinking of it like a financial debt. Refactoring for policymakers technical debt for policymakers. When you have got a nagging tiny gas leak on a city block, a literal smell will lead. Software systems are prone to the build up of cruft deficiencies in internal quality that make it harder than it would ideally be to modify and extend the system further.
This can lead to the accumulation of technical debt, which is then increased when changes are merged. Track technical debt to improve your development practices june 27, 2016 sei blog. Introduction to the technical debt concept agile alliance. Technical debt also known as design debt or code debt, but can be also related to other technical endeavors is a concept in software development that reflects the implied cost of additional rework. Technical debt is a concept in programming that reflects the extra development work that arises when code that is easy to implement in the short run is used instead of applying the best overall. Describing things this way puts code into a pseudofinancial lingo that noncoders can understand easily, and facilitates a. The customer has to realize in which ways this will cost him.
Project management and technical debt agile alliance. All functional tests should pass with the same results after the code has been refactored. From the foreword by grady booch, ibm fellow and chief scientist for software engineering, ibm research evolving software inevitably accumulates technical debt, making maintenance increasingly painful and expensive. Software refactoring has been recognised as a valuable process during software development and is often aimed at repaying technical debt.
But when code is just bad, refactoring is way, way harder. Functional debt vs technical debt in software development. Refactoring is modifying the internal structure of code without changing its behaviour. What delights me about this present book is its focus on technical debt and refactoring as the actionable means to attend to it. Technical debt might not be due to objectively bad code, but rather different styles from different engineers. Luckily, our product owners are receptive and understand the need for refactoring. If you are able to estimate roughly the time needed for fixing what is not right into your code, the principal of your debt, you could compare this information to other project data. Evolving software inevitably accumulates technical debt, making maintenance increasingly painful and expensive. Refactoring is the cure for technical debt but only if. If technical debt exceeds the level where some regular refactoring or a few technical debt stories can address it, the team may need to dedicate one or more.
You will see organizations struggling with their technical debt and. Refactoring is intended to improve the design, structure, andor. In technical terms, bad code is tightly coupled the. Refactoring and technical debt are important concepts, especially so in agile software development. Code refactoring is the process of restructuring existing computer codechanging the factoringwithout changing its external behavior. If you do not leave todos in the code, you will most likely forget about the issue.
The concept of technical debt is a metaphor created by ward cunningham to describe the complexity in software projects. Most managers and developers never have the luxury of starting a project from scratch. Should you create user stories to handle such technical tasks and technical debt, or not. Refactoring helps you understand other peoples code. Technical debt is commonly associated with extreme programming, especially in the context of refactoring.
The extra effort that it takes to add new features is the. It makes code harder to build, run, and deploy and may even cause major production outages. Refactoring and technical debt extreme uncertainty. In this first post, we explain what technical debt is and why its important. Ward cunningham coined the term, and martin fowler has some good takes on the subject, and ron jeffries as well. Functional debt vs technical debt in software development just like in finance, in the development process debt is not really something you want. If you have to deal with someone elses dirty code, try to refactor it first. A metaphor that has gained popularity in the last 20 years is that of technical debt. The further in technical debt you go, the more it takes just to keep the lights on. This article is about refactoring the only thing you can do to reduce technical debt after the project has already been. Product design debt versus technical debt at andrewchen. Mary poppendieck gives a definition of technical debt in her upcoming book leading lean software development.
Building for inevitable change paperback agile software development sterling, chris on. Recently on our project we did a technical debt retrospective. In the case of architectural refactoring the necessity of redesign may be obvious enough, since it may be a pain those developers. In simplistic terms, technical debt shows up on the keepthelightson vs. Its an old concept that i remember talking about, maybe. To illustrate our definition, we offer a few stories about technical debt in software development projects. Technical debt arises when a software product has been built or amended without full care f or structure and extensibility. Given that refactoring is the primary means to repay technical debt, this metaphor provides the why for refactoring. The two main reasons for refactoring are poorly written legacy code and evolving solutions as a problem is. Even if all of the authors are excellent, the book. The two are inextricably linked in the agile space, meaning, refactoring is a way of removing or reducing the. This article is about refactoring the only thing you can do to reduce technical debt after the project has already been designed and started.
In our book we look at the concept of smells and refactoring in the context of technical. The product backlog and technical debt ian mitchell. Examples of technical debt principles of technical debt. Any discussion on refactoring must also include the notion of technical debt. Thus, refactoring these libraries, adding better unit tests, and associated activity is time well spent but does not necessarily address debt at a systems level. Basically we brainstormed on the wall all the tech debts we thought we had incurred since the beginning of the. The authors, based on their extensive experience, categorise the major design problems. Explain what technical debt means, and how it makes development slow down to a halt if it gets too high. And even if you have time for it in the future, you will not remember to fix. The authors, based on their extensive experience, categorise the major design problems smells that come up in software, and lucidly explain how these can be solved with appropriate refactoring.
Refactoring is the cure for technical debt but only if you take it. Its like writing a book where each paragraph is written by a different author. Although we usually regard refactoring as a softwarerelated activity, refactoring, like technical debt, is a concept that can apply to any technological asset. Technical debt also known as design debt 1 or code debt, but can be also related to other technical endeavors is a concept in software development that reflects the implied cost of. Amazons tabs are a classic example of product design debt and the refactoring process to pay it down incrementalism creates technical debt, and also product design debt most startups these days build. Refactoring is the restructuring of existing code as part of the development process. Technical debt is widely regarded as a bad thing that should be paid back as soon as possible, however it can be a strategy that helps balance shortterm wins and longterm productivity. The technical debt concept is an effective way to communicate about the need for refactoring and improvement tasks related to the source code and its architecture. The more changes made in isolation, the greater the total technical debt. Refactoring is modifying the internal structure of code without.
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