Introduction to Software Engineering (2+1 SWS) Winter Term 2009 / 2010 Dr. Michael Eichberg Vertretungsprofessur Software Engineering Department of

Transcription

1 Introduction to Software Engineering (2+1 SWS) Winter Term 2009 / 2010 Dr. Michael Eichberg Vertretungsprofessur Software Engineering Department of Computer Science Technische Universität Darmstadt

2 Dr. Michael Eichberg Fachgebiet Software Engineering Department of Computer Science Technische Universität Darmstadt Introduction to Software Engineering Computer Aided Software Engineering

3 Dr. Michael Eichberg Fachgebiet Software Engineering Department of Computer Science Technische Universität Darmstadt Introduction to Software Engineering Revision-control Systems

4 Making Sense of 4 Recommended Reading Source: Author: ACM Queue Bryan D Sullivan

5 All types of revision-control systems support a basic set of tasks. 5 Track the history of files This enables you to answer questions such as: Who did which changes? When was a change made? Why was a change made? Recreate project state...

6 All types of revision-control systems support a basic set of tasks People can work on independent sub-projects (usually referred to as branches) Branches are typically used to manage the maintenance of releases that are no longer actively developed RCS enables you to integrate changes made in a subproject back into the main project

7 Branches & Merging 7 BAT3XML

8 Typical issues related to branching and merging 8 The same section is modified in different ways Code in a branch depends on functionality that has changed in the other branch (Most likely, the project will break when merged.) Files are copied and / or renamed and someone wants to check in some changes w.r.t. the old file How branches and merges are handled differs significantly between different types of revision-control systems.

9 We can distinguish between two basic types of revision-control systems: centralized and distributed. 9 Centralized CVS Subversion (SVN) Perforce Distributed Git Mercurial

10 Both types of revision-control systems have different trade-offs. Centralized Distributed 10 Client-server model; a single server hosts a project s metadata commits are server based no explicit support for branches; branches are handled by convention better suited for binary data enable fine-grained rights management Operate in a peer-to-peer manner each copy (repository) contains all of a project s history and metadata a working copy contains a snapshot of the project s files commits are local until they are shared fetching remote changes and merging them with the local copy is decoupled

11 Git s / Mercurial s bisect command facilitates finding bugs. 11 does not contain the specific bug 1. checkout by bisect Question: Does this version contain the bug? No, use revision (L+X)/2 2. checkout by bisect Question: Does this version contain the bug? Yes, revision that introduced the bug is found contains a specific bug Revision A L X Time