Git for dummies

As the source code is handled by the version control system Git, it's useful to know some features used.

Submodules

The repository uses submodules, which normally are handled directly by the Makefile, but sometimes you want to be able to work with them manually.

Following are the steps to manually get the submodules:

git clone https://[email protected]/jaseemabid/Networks-Lab.git
git submodule init
git submodule update

Or:

git clone https://[email protected]/jaseemabid/Networks-Lab.git
git submodule update --init

Or:

git clone --recursive https://[email protected]/jaseemabid/Networks-Lab.git

If you want to work inside a submodule, it is possible, but first you need to checkout a branch:

cd src/docs
git checkout master

After you've committed your changes to the submodule, you'll update the jquery project to point to the new commit, but remember to push the submodule changes before pushing the new jquery commit:

cd src/docs
git push origin master
cd ..
git add src/docs
git commit

The makefile has some targets to simplify submodule handling:

`make update_submodules`

checks out the commit pointed to by jquery, but merges your local changes, if any. This target is executed when you are doing a normal make.

`make pull_submodules`

updates the content of the submodules to what is probably the latest upstream code.

`make pull`

make a make pull_submodules and after that a git pull. if you have no remote tracking in your master branch, you can execute this command as make pull REMOTE=origin BRANCH=master instead.

cleaning

If you want to purge your working directory back to the status of upstream, following commands can be used (remember everything you've worked on is gone after these):

git reset --hard upstream/master
git clean -fdx

rebasing

For feature/topic branches, you should always used the --rebase flag to git pull, or if you are usually handling many temporary "to be in a github pull request" branches, run following to automate this:

git config branch.autosetuprebase local (see man git-config for more information)

handling merge conflicts

If you're getting merge conflicts when merging, instead of editing the conflicted files manually, you can use the feature git mergetool. Even though the default tool xxdiff looks awful/old, it's rather useful.

Following are some commands that can be used there:

Ctrl + Alt + M - automerge as much as possible
b - jump to next merge conflict
s - change the order of the conflicted lines
u - undo an merge
left mouse button - mark a block to be the winner
middle mouse button - mark a line to be the winner
Ctrl + S - save
Ctrl + Q - quit

jaseemabid/git for dummies.md