GitHub Subtrees

I have been familiar with git ever since I started using Linux. I used ‘git clone’ quite a bit to compile and install latest versions of software, but that’s where most of my ‘familiarity’ was limited to. I did mess around with creating local repositories and committing but that’s all. We used SVN at work, so most of my version control knowledge is based on SVN. So, I am still figuring out lot of git stuff that most people probably already know.

So, I was looking for a way to have a single repository for a class and all my projects for that class would be stored under that repository. That’s when I came across this nifty little feature here called Git subtree merges, which allows you to manage multiple projects under a single repository.

The workflow as I understand it is as below:

  1. I created a repository called advanced-data-structures. This is my main repository.
  2. Then I created another repository called RedBlackEventCounter. This holds the actual project code. Made changes, committed and pushed to this remote.
  3. Then I added the remote of RedBlackEventCounter to the master of advanced-data-structures.

    git remote add -f RedBlackEventCounter

  4. Merged RedBlackEventCounter into advanced-data-structures.

    git merge -s ours --no-commit RedBlackEventCounter/master

  5. Copied the git data of RedBlackEventCounter repository into a new directory in the advanced-data-structures repository.

    git read-tree --prefix=RedBlackEventCounter/ -u RedBlackEventCounter/master

  6. Commit and push the changes.

    git commit -m "Added RedBlackEventCounter reference into advanced-data-structures"
    git push origin master

Now, this subtree doesn’t automatically sync with the changes made in the upstream repository. GitHub’s documentation recommends using the below command to update:

git pull -s subtree remotename branchname

[Update – 03/15/2016]: The above command seems to work properly now. I’m not sure what had happened earlier; probably some mistake on my part. Need to dig deeper. So my workflow is now:

git pull -s subtree RedBlackEventCounter master

git push origin master

The below is not needed anymore.

But for some reason, it doesn’t work out for me. I keep getting the error

error: Entry %filename% overlaps with %filename%. Cannot bind.

So, what I do is create a temporary directory and pull in everything from subtree remote. Copy over everything from this directory to the subtree directory. Remove the temporary directory, stage all, commit and push.

mkdir RedBlackTemp
git read-tree --prefix=RedBlackTemp/ -u RedBlackEventCounter/master
git commit -m "Pulled upstream changes"
cp -rf RedBlackTemp/* RedBlackEventCounter/
git rm -rf RedBlackTemp
git add .
git commit -m "Merged upstream changes into master"
git push origin master

I know it is quite cumbersome to do this everytime you make a change. I guess there is a better way that I just don’t know yet. So, if anybody has an idea, please let me know.

GNOME – Restore default folder icons

Recently, my laptop battery got drained completely and the system shut down incorrectly. This resulted in my NTFS data drive not getting unmounted properly. The videos, music, pictures and documents folders in my NTFS drive are linked to the Home folder in my Fedora install. When I booted my system back up I was not able to access my music and videos. I figured, probably some issue with auto-mounting the NTFS drive at boot, so unmounted and remounted the drive and the issue was fixed. I rebooted once more to confirm and the auto-mounting was working. I had access to my music and videos again. But there was a different issue.

You know how the Documents, Music, Pictures and Videos folders all have specialized icons? Well, they were gone and were replaced with a generic folder icon. After looking around for some time, I got to the root cause. It turns out that my /home/sayak/.config/user-dirs.dirs had got corrupted. This is how the file is supposed to look like:

# This file is written by xdg-user-dirs-update
# If you want to change or add directories, just edit the line you're
# interested in. All local changes will be retained on the next run
# Format is XDG_xxx_DIR="$HOME/yyy", where yyy is a shell-escaped
# homedir-relative path, or XDG_xxx_DIR="/yyy", where /yyy is an
# absolute path. No other format is supported.

In my case, the documents, music etc. directories were pointing to $HOME i.e. XDG_DOCUMENTS_DIR=”$HOME/”. Most likely, a result of the botched auto-mounting attempt from earlier.

To fix it, I just had to update the file to point to the correct locations. So, I deleted the file and executed the below command:


And, that fixed it.

Fedora 23 and screen tearing

As I mentioned in my Fedora 23 review, I am very happy with this new release. So, I was a bit disappointed when I notice the issue with screen tearing. Now this is probably an issue with my particular set up and a lot of people may not run into this issue.

I have an Acer Aspire V5 with an integrated Intel HD 4400 and nVidia GT 750M and I use bumblebee for dynamic switching. So, by default the system runs on the Intel card. I noticed that when I move any window there is some tear. Naturally, I went on google looking for a fix for the issue. And I found this post on Ask Fedora. Basically the fix is to create the file /etc/X11/xorg.conf.d/20-intel.conf and have the below content in it:

# /etc/X11/xorg.conf.d/20-intel.conf
Section "Device"
Identifier "Intel Graphics"
Driver "intel"
Option "AccelMethod" "sna"
Option "TearFree" "true"

And then reboot! The issue should be fixed.