Version Control Flashcards
Version Control System (VCS)
A system for storing and retrieving variants of items.
Version
A collection of items is a variant of the collection resulting from some modification of one or more of its constituents
Revision
A version stored in a VCS
Baseline
The first revision of a collection of items storied in a VCS
Repository
The store in which a VCS records revisions
Checked in/Committed
When a version is stored in the repository
Checked out/updated
When a version is retrieved from the repository
Working copy
A checked out version of an item
Initial Commit
A collection of items enters a VCS as this.
Trunk
Main line of succession of revisions s is called a trunk and the other lines of succession are branches
Tags
Identifiers to keep track of each revision.
Head revision/tip
The latest revision of a branch
2 main policies to control incompatible commits
File Locking
Concurrent modification and merge
File Locking
Policy to control incompatible commits (1 out of 2) : Items can be retrieved from repository with individual files checked out either read-only or for modification. When for modification files locked, so no one else can check it out for modification until checked in again. One at a time check-out. Avoid incompatible commits.
Concurrent modification and merge
Policy to control incompatible commits (2 out of 2) : Anyone can edit at same time, but once one person commits a new version of working copy, the next person who tries to commit will not be able to until they update his or her working copy. VCS attempts to create new working copy incorporating all changes.
Conflict
If same portion of a file has changes in both the repository and in the old working copy. Then they are asked to resolve it. Resulting version of working copy is then stored as the current revision.
Centralized VCS
It has one repository
Distributed VCS
It has several repositories none of which are considered authoritative
- introduces problems b/c new opportunities for conflicting revisions because a commit to a repository can cause a conflict with a changed revision in that repository there can be conflicts between revisions in different repositories. Only good if there is some advantage to distrusting the repository such as greatly decreased check-in and check-out times
Subversion is Centralized or Descentralized?
Centralized
What kind of commits are in SVN
Atomic
How are SVN repositories referred
To using URLs so that clients can get to them across the internet
How does SVN record entire directory trees
As revisions, so when you commit a file, everything in the directory tree is considered a new revision
How does SVN distinguish Revisions
Natural numbers (empty project has version 0) first commit is version 1 and so on
What happens if someone makes a commit in a project you are working on in SVN?
Your working copy will not be modified and you will not get any sort of notice that this has occurred. Must always ask for the latest version by doing an update.
Always update before doing anything
What happens if you make changes to the same files as someone else and they have already committed their changes SVN?
When you try to commit the check in will fail. Then you have to update your working copy, which will merge as many changes as it can. Conflicts that it cannot resolve will ask you to resolve manually
What kind of tool in SVN/ how can you access its features?
Through the command line
What is trunk in SVN contain?
The code that will appear in the next major release
What are branches in SVN contain?
Copy of the trunk that is used for active development
What is a tag in SVN?
A “frozen” copy of the code that in not used for active development
Platform Branches
Made to port the code to a different platform
Experimental Branches
Made to try experimental technologies
Bug-Fix Branches
Made to correct a serious defect
Release Tag
A copy of the code made at release-time
Pre-Bug-Fix Tags
A copy of the code made to record its state before a major bug fix
Post-Bug-Fix Tags
A copy of code made to record its state after a major bug fix
Normal Work Cycle of SVN
Update
Modifications/Additions
Prior to Check-IN/Commit (update)
Check-In/Commit
When to Commit?
When a substantial change is made that can stand on its own and all related files should be committed together.
