Git

Introduction

The primary source code management system for the Mu2e Offline software is a git repository that is hosted on the Fermilab Redmine site. Git is a popular open-source software version control system and Redmine is a software project management system which contains, for each project, a log, a wiki (which may contain useful info), and possibly gantt charts and bug tracking along with the git respositories.

Based on the git repository's url, you can check out code, and, if you are a code developer, check in modifications. NB, when committing code, please follow these [#gitCommit|mu2e conventions] only. Git also has capabilities for tagging code, tracking history and supports splitting off and merging development branches, among many other features.

Some older parts of Mu2e software is managed using other source code management systems. Some code, both critical and specialized, is in other, smaller repositories. See Repositories below for more details on repositories.

See the references for more details on Redmine and git.

Quick Start

Please also see the basic code recipe for an introduction to setting up the environment, checking out code and building.

If you are going to commit anything, you must understand and follow the [#gitCommits|mu2e commit instructions]

If this is the first time you are using git in the mu2e environment, please follow the few steps listed here under "Configure git" in order to set up your ~.gitconfig.

A more detailed introduction to mu2e repositories is mu2e here.

• checkout the main repository
  • readonly:

    git clone http://cdcvs.fnal.gov/projects/mu2eofflinesoftwaremu2eoffline/Offline.git

  • with kerberos authentication for committing code

    git clone ssh://p-mu2eofflinesoftwaremu2eoffline@cdcvs.fnal.gov/cvs/projects/mu2eofflinesoftwaremu2eoffline/Offline.git

• checkout the head to a local working branch, here named "work" (recommended)

git checkout -b work

• see the history of a file

git log fileSpec

• list tags

git tag -l

• checkout a tag or branch into the working area

git checkout tagOrBranchName 

• update the local repository

git fetch

• update the local repository and checkout the head into the working area

git pull

• see what the status is

git status

• command line help

git status help

• git browser (to see a graphical history of commits)

gitk --all

Please see the references below or many web resources for details on git concepts, commands and features. If you are going to commit anything, you must understand and follow the commit workflows.

Workflows for committing code

We are using two workflows when changed need to be committed back to the repository.

• Minor development, or "hot fix". This is for small changes, such as changing fcl parameters, fixing bugs, adding minor features, or starting a new module. These modifications are committed directly to the head and should leave the head in a state that compiles and runs. There should be no branch visible afterwards. The changes should not require any special warning to users. This pattern is copied from mu2e commit instructions the original redmine page.

• Major development. This is intended for development which will take more than a day or, perhaps up to months, and may involve multiple contributors and validators, or should be documented in the git repository for some time. They may also mark breaking changes, or need to be coordinated with product changes, other branches, or tags. Currently we plan to leave these branches visible in the repository until they are no longer of interest, at which time they may be archived so as to not clutter the repo forever.

Repositories

One important piece of the mu2e offline code is the BTrk UPS product, which contains our Kalman track fit code, and is stored in the BTrk github repo.

All of the rest of the mu2e Offline code and tools are in Redmine repositories. You can browse all Redmine projects and mu2e Redmine. The mu2e Redmine has subprojects (and sub-subprojects) and each has a repository associated with them. For example in the Standalone subproject, there is a sub-subproject Mu2eCCFC. In addition, the main mu2e Offline repository has sub-repositories which can be seen on the right sidebar menu on the repository main page. An example is the dhtools sub-repo.

Here is a (possibly incomplete) list of the repositories.

content	user	name	alias
	p-mu2e_artdaq	mu2e_artdaq
	p-mu2e_artdaq	mu2e_artdaq-core
F-C limit setting	p-mu2eccfc	mu2eccfc-mu2eccfc	mu2eccfc.git
	p-mu2e-daq-firmware	mu2e-daq-firmware
	p-mu2e-daq-firmware	mu2e-daq-firmware-dtc
	p-mu2e-dcs	mu2e-dcs
	p-mu2e_detector_construction_db	mu2e_detector_construction_db
grid tools	p-mu2egrid	mu2egrid
Offline	p-mu2eofflinesoftwaremu2eoffline	mu2eofflinesoftwaremu2eoffline	Offline.git
Jenkins	p-mu2eofflinesoftwaremu2eoffline	mu2eofflinesoftwaremu2eoffline-codetools	codetools.git
data handling	p-mu2eofflinesoftwaremu2eoffline	mu2eofflinesoftwaremu2eoffline-dhtools	dhtools.git
	p-mu2eofflinesoftwaremu2eoffline	mu2eofflinesoftwaremu2eoffline-geomdisplay	geomdisplay.git
satellite releases	p-mu2eofflinesoftwaremu2eoffline	mu2eofflinesoftwaremu2eoffline-satellite
	p-mu2eofflinesoftwaremu2eoffline	mu2eofflinesoftwaremu2eoffline-test
obsolete	p-mu2eofflinesoftwaremu2eoffline	mu2eofflinesoftwaremu2eoffline-validation	validation.git
Stntuple framework	p-mu2eofflinesoftwarestntuple	mu2eofflinesoftwarestntuple	Stntuple.git
	p-mu2eofflinesoftwareuser	mu2eofflinesoftwareuser-betasource	betasource.git
	p-mu2eofflinesoftwareuser	mu2eofflinesoftwareuser-example01	example01.git
	p-mu2eofflinesoftwareuser	mu2eofflinesoftwareuser-streamline
	p-mu2epbarmodels	mu2epbarmodels
	p-mu2e-raw-data	mu2e-raw-data
	p-mu2e-tools	mu2e-tools-bintools	mu2ebintools
FileTools	p-mu2e-tools	mu2e-tools-filetools	mu2efiletools
FileTools	p-mu2e-tools	mu2e-tools-mu2efilename	mu2efilename
generate_fcl	p-mu2e-tools	mu2e-tools-tools	mu2etools

Creating a Redmine subproject is done by the "add subproject" button on the Redmine project web page. Creating a sub-repository associated to the main offline repo is explained in the mu2e instructions and SCD instructions. Write privileges to each repository can be controlled by the .k5login contents of each group username associated with the repo - note that this file should be edited by the Redmine project web page (settings->members), not directly. The login to the group account is controlled by the .admin file.

A git repository is accessed through a url and the url can be read-only or read/write, which allows commits back to the repo. Taking values from the table of Redmine repos above, a repo without an alias will have read-only and read/write urls:

http://cdcvs.fnal.gov/projects/name
ssh://user@cdcvs.fnal.gov/cvs/projects/name

and if it has an alias:

http://cdcvs.fnal.gov/projects/name/alias
ssh://user@cdcvs.fnal.gov/cvs/projects/name/alias

References

• mu2e git and CVS
• mu2e git commit instructions
• git home Documentation reference
• redmine repository browser
• Fermilab redmine
• talk at the Software and Simulation Meeting, Sept 17, 2014.
• Marc P's suggested git workflow for simple git projects
• Fermilab git workshop and related materials
• managing and creating new redmine repositories