Git: Pulling

Original chapter reference: Chapter 23: Pulling. The command options and documentation recipes below are fully transcribed from Git Notes for Professionals.

Parameters Details --quiet No text output -q shorthand for --quiet verbose text output. Passed to fetch and merge/rebase

--verbose

commands respectively. -v shorthand for --verbose Fetch new commits for submodules? (Not that this is not a

--[no-]recurse-submodules[=yes|on-demand|no]

pull/checkout)

Unlike pushing with Git where your local changes are sent to the central repository's server, pulling with Git takes the current code on the server and 'pulls' it down from the repository's server to your local machine. This topic explains the process of pulling code from a repository using Git as well as the situations one might encounter while pulling different code into the local copy.

Section 23.1: Pulling changes to a local repository

Simple pull

When you are working on a remote repository (say, GitHub) with someone else, you will at some point want to share your changes with them. Once they have pushed their changes to a remote repository, you can retrieve those changes by pulling from this repository.

git pull

Will do it, in the majority of cases.

Pull from a different remote or branch

You can pull changes from a different remote or branch by specifying their names

git pull origin feature-A

Will pull the branch feature-A form origin into your local branch. Note that you can directly supply an URL instead of a remote name, and an object name such as a commit SHA instead of a branch name.

Manual pull

To imitate the behavior of a git pull, you can use git fetch then git merge

git fetch origin # retrieve objects and update refs from origin
git merge origin/feature-A # actually perform the merge

This can give you more control, and allows you to inspect the remote branch before merging it. Indeed, after fetching, you can see the remote branches with git branch -a, and check them out with

git checkout -b local-branch-name origin/feature-A # checkout the remote branch
# inspect the branch, make commits, squash, ammend or whatever
git checkout merging-branches # moving to the destination branch
git merge local-branch-name # performing the merge

This can be very handy when processing pull requests.

Section 23.2: Updating with local changes

When local changes are present, the git pull command aborts reporting :

error: Your local changes to the following files would be overwritten by merge

In order to update (like svn update did with subversion), you can run :

git stash
git pull --rebase
git stash pop

A convenient way could be to define an alias using :

Version < 2.9
git config --global alias.up '!git stash && git pull --rebase && git stash pop'
Version ≥ 2.9
git config --global alias.up 'pull --rebase --autostash'

Next you can simply use :

git up

Section 23.3: Pull, overwrite local

git fetch
git reset --hard origin/master

Beware: While commits discarded using reset --hard can be recovered using reflog and reset, uncommitted changes are deleted forever.

Change origin and master to the remote and branch you want to forcibly pull to, respectively, if they are named differently.

Section 23.4: Pull code from remote

git pull

Section 23.5: Keeping linear history when pulling

Rebasing when pulling

If you are pulling in fresh commits from the remote repository and you have local changes on the current branch then git will automatically merge the remote version and your version. If you would like to reduce the number of merges on your branch you can tell git to rebase your commits on the remote version of the branch.

git pull --rebase

Making it the default behavior

To make this the default behavior for newly created branches, type the following command:

git config branch.autosetuprebase always

To change the behavior of an existing branch, use this:

git config branch.BRANCH_NAME.rebase true

And

git pull --no-rebase

To perform a normal merging pull.

Check if fast-forwardable

To only allow fast forwarding the local branch, you can use:

git pull --ff-only

This will display an error when the local branch is not fast-forwardable, and needs to be either rebased or merged with upstream.

Section 23.6: Pull, "permission denied"

Some problems can occur if the .git folder has wrong permission. Fixing this problem by setting the owner of the complete .git folder. Sometimes it happen that another user pull and change the rights of the .git folder or files.

To fix the problem:

chown -R youruser:yourgroup .git/