Page History

Git References

Git has many similarities to other source code version control systems, but there are important differences as well. There are a number of useful references to help you master your use of git: 

• git Reference -- read this first to get a high-level overview in 15 minutes

• Learn.git series -- another git introduction, including screen-casts (note: the text may be somewhat more informative than the embedded screencasts)

• http://git-scm.com/course/svn.html -- git for svn users (but please, read the links above as well)

• Pro Git book -- Written by Scott Chacon. Get to know git in more depth (~2 hrs?)

• Git Book -- similar to the Pro Git book, but a bit more comprehensive

• Useful git tips -- some useful less well known tips

• An explanation from Mario Juric of how to think about git and how it internally does things. It also discusses merging and fast-forwards. Note that most of this is covered in the tutorials above, but if you're still confused, try reading it.
• A video by Phil Marshall on using git and GitHub.

A cookbook style document, Git Crash Course, may help you understand the use of git for LSST/DM code development. 

Development Policies

Branch Management Policies

LSST DM code development is governed by various policies to maintain order in a large, distributed, multi-developer project. The policies are embodied in the workflows described below. Note: the branch management policy described here is drawn from the page: DM Branching Policy which is the authoritative source. 

Git Workflow

The following workflow is based on github-flow: 

...

1. Verify which branch you are on. Ordinarily that would be the git master branch: 

   Code Block
   language bash
   git branch or git status

2. Create a new branch for ticket DM-9999, both locally and remotely: 

   Code Block
   language bash
   git checkout -b tickets/DM-9999 git push -u origin tickets/DM-9999

3. Create or modify the source code. Commit often: Push periodically: 

   Code Block
   language bash
   git commit -a git push

4. Ask for a review. 

5. After your code passes review, merge it into master: 

   Code Block
   language bash theme Confluence
   git checkout master git pull master git merge --no-ff tickets/DM-9999 git push

Git Tag Policy

When creating tags meant for the public (e.g., release tags), always use annotated tags (that is, 'git tag -a') or signed tags ('git tag -s'). These store the information on who created the tag, when, can be cryptographically signed, and can have a message attached to them. For example: 

...

git tag -s -m "Version 4.7.0.0" 4.7.0.0

Summary of Git Operations

The following illustrates the sequence of operations one ordinarily executes with git during source code development. 

...