Annotated Git session using the sim-recon repository

I needed to update one monitoring plugin file, which was in a non-git directory in my home area. This was the best way to go about it:

Make a local copy of the entire sim-recon repository for myself. This took about 5 seconds. OR... be sure to checkout the master branch and update it.

cd ~
mkdir git
cd git
git clone https://github.com/JeffersonLab/sim-recon

Check that the plugin in the repository is what I think it is

cd sim-recon/src/plugins/monitoring/CDC_online/
git status

Copy in my updated file

cp ~/online/plugins/CDC_online/JEventProcessor_CDC_online.cc .
git status

# On branch master
# Changed but not updated:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#	modified:   JEventProcessor_CDC_online.cc
#

List the changes between this copy and the original and make sure that they are all mine (use space to get to next page)

git diff

Make a new branch to contain and label my change

git branch cdcpluginupdate
git status

# On branch master
# Changed but not updated:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#	modified:   JEventProcessor_CDC_online.cc
#
no changes added to commit (use "git add" and/or "git commit -a")

Switch to the new branch, check the status and list the branches.

git checkout cdcpluginupdate

M	src/plugins/monitoring/CDC_online/JEventProcessor_CDC_online.cc
Switched to branch 'cdcpluginupdate'

git status

# On branch cdcpluginupdate
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#	modified:   JEventProcessor_CDC_online.cc
#

git branch 
* cdcpluginupdate
  master

Add the file to the list of files to be committed/uploaded to the repository

git add JEventProcessor_CDC_online.cc

git status

# On branch cdcpluginupdate
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#	modified:   JEventProcessor_CDC_online.cc
#

Commit change to the local repository

git commit -m "updated cdc_online for fa125 new format"

Send it to the remote repository. The first branchname given is the local name, the second is the new name on the remote repo (usually no need to change it).

git push origin cdcpluginupdate:cdcpluginupdate 

error: The requested URL returned error: 403 Forbidden while accessing https://github.com/JeffersonLab/sim-recon/info/refs
fatal: HTTP request failed

This did not work, check the age of git

git —-version

git version 1.7.1

Try again from a different computer with a more recent git, as 1.7.1 is known to be problematic. (At CMU, try Victor or usr/local/bin/git)

git —-version

git version 2.5.0

git push origin cdcpluginupdate:cdcpluginupdate 

Counting objects: 7, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (7/7), done.
Writing objects: 100% (7/7), 1.43 KiB | 0 bytes/s, done.
Total 7 (delta 6), reused 0 (delta 0)
To https://github.com/JeffersonLab/sim-recon

* [new branch]      cdcpluginupdate -> cdcpluginupdate

ONE MORE THING. Need to issue the pull request on the web page (for someone to approve the addition)

Go to https://github.com/JeffersonLab/sim-recon and sign in on the RHS.

Below ‘Simulation and Reconstruction for GlueX’ there was a pale yellow box showing the name of my new branch, and on the RHS inside the box was a green button ‘compare and pull request’. Click it.

Now wait for someone else to merge it. (or not).

Other git things

List tags: git tag -l
Checkout tag: git checkout tagname
Revert to tag called tagname: git reset --hard tagname

Updating my local branch with changes in the remote master, eg to make my_branch consistent with tag 4.17.0:

git checkout master
git pull
git checkout 4.17.0
git branch tag4.17.0

git checkout my_branch
git merge tag4.17.0
git commit

I followed instructions to start up emacs and start the git server (M-x server-start, M is shift+command), typed a comment into the buffer, saved and exited emacs.

Updating a remote branch

"git fetch" gets the list of branches from the remote repo

git fetch 
git checkout <branchname> 
git merge master 

Save comment in editor and leave: :q

git push origin <branchname>:<branchname>