Why Version Control System (VCS)

Why Version Control System (VCS)

Why version control?

Scenario 1:

• Your program is working

• You change “just one thing”

• Your program breaks

• You change it back

• Your program is still broken — why?

Has this ever happened to you?

Why version control? (part 2)

• Your program worked well enough yesterday

• You made a lot of improvements last night…

• You need to turn in your program now

• Has this ever happened to you?

Version control for teams

Scenario:

• You change one part of a program — it works

• Your co-worker changes another part — it works

• You put them together — it doesn’t work

• Some change in one part must have broken something in the other part

• What were all the changes?

Teams (part 2)

Scenario:

• You make a number of improvements to a class

• Your co-worker makes a number of differentimprovements to the sameclass

How can you merge these changes?

Version control systems (VCS)

A version control system (often called a source code control system) does these things:

• Keeps multiple (older and newer) versions of everything (not just source code)

• Requests comments regarding every change

• Allows “check in” and “check out” of files so you know which files someone else is working on

• Displays differences between versions

Benefits of version control

1. For working by yourself:

• Gives you a “time machine” for going back to earlier versions

• Gives you great support for different versions (standalone, web app, etc.) of the same basic project

2. For working with others:

• Greatly simplifies concurrent work, merging changes