Theory and practice – migrating your legacy code into our modern test driven development world.

Theory and practice  migrating your legacy code into our modern test driven development world.Hartmann, Jankowfsky, RinneLegacy Code?Wikipedia says „Legacy code is source code that relates to a no-longer supported or manufactured operating system or other computer technology. The term can also mean code inserted into modern software for the purpose of maintaining an older or previously supported feature“Jankowfsky, Rinne – Mayflower/swoodooAgenda- Where are we now, and why?- Ammunition!- Refactor!Bad News? -> WorkshopJankowfsky, Rinne – Mayflower/swoodooWho we areLars Jankowfsky:- CTO and (Co)Founder swoodoo.com- (Co)Founder of OXID eSales. Refactored OXID eShop during 1.5 years with 10 developers.Thorsten Rinne:- Senior Developer & Team Lead at Mayflower GmbH- Founder and main developer of phpMyFAQJohann Peter Hartmann:- CTO and Founder of Mayflower GmbH- CEO and Founder of SektionEins GmbHJankowfsky, Rinne – Mayflower/swoodooWho are you?- What‘s your profession?- Sofware company or agency?- What‘s your team size?- Using MVC?- Who does other languages, too?- Using agile methods?- Using continuous integration?- Using unit tests?Jankowfsky, Rinne – Mayflower/swoodooWhat about your projects?- What‘s your average project lifetime?- Is there PHP code more than 5 years old?- How many lines of code?- How many change requests per year?- Has there been a specification?- Were all features in the first released version implemented like they‘re specified in the specification?Jankowfsky, Rinne – Mayflower/swoodooTypical problems?- Typical legacy applications- Started some years ago with PHP 4- written in Spaghetti code- half procedual, half object-orientated- „PHP 4“ OOP- using old, unmaintained libraries like PEAR::DBJankowfsky, Rinne – Mayflower/swoodooPHP, made in 2000- no coding standards- no PHPDoc- no Design Patterns- few separation of concerns- has been changed a lot - no refactoring, because „it worked“ - updated to run with php 4 in 2003- updated to run with php 5 in 2006Jankowfsky, Rinne – Mayflower/swoodooBig ball of mudhttp://en.wikipedia.org/wiki/Big_ball_of_mudA Big Ball of Mud is a haphazardly structured, sprawling, sloppy, duct-tape-and-baling-wire, spaghetti-code jungle.These systems show unmistakable signs of unregulated growth, and repeated, expedient repair....Jankowfsky, Rinne – Mayflower/swoodooEnough Ammunition?- change requests get more and more expensive- bug rate is increasing- clearly a dead-end street!- team motivation decreases- hard to bring in new members into the team- deprecated functions cause problems in future PHP releasesJankowfsky, Rinne – Mayflower/swoodoo