Replacing Local Git Branches with Remote Versions: An In-Depth Guide

As developers collaborate on Git repositories, their local branches often get out of sync with the remote origin. Instead of merging remote changes, they sometimes want to fully reset local branches to match the remote. This guide dives deep on how to overwrite local branch history by resetting to remote versions.

How Git Remotes and Branches Work

Before resetting branches, it helps to understand how Git tracks branches and remotes.

A Git remote is essentially a connection to a shared repository:

The remote servers act as a single source of truth. Local clones of the repository can make commits independently, but they eventually synchronize work with the central remote.

A Git branch represents an independent line of development:

By default, Git repositories have a main branch called master. Developers create new branches to work on features without impacting main line.

Relating Branches and Remotes

In your local repository clone, you can access multiple branches. But there are also remote-tracking branches that serve as bookmarks to branches on remote servers:

origin/master
origin/new-feature

So when you interact with remotes, you‘re communicating bookmark branches as well as your local named branches.

Why Reset Local Branch to Remote?

Resetting entirely to a remote branch is drastic since it overwrites local commits. Before undertaking this, it‘s wise to understand scenarios where this might make sense:

• Replace stale work: Your local feature branch has fallen behind due to new activity on remote master. Resetting to origin/master lets you start fresh.
• Undo local mistakes: You made commits to local branch that broke things, so you want to discard local work.
• Retry failed features: You tried developing a feature but want to start again from the remote state.

Risks of Overwriting Local Changes

While resetting local branches seems easy enough, developers should weigh a few risks:

• Valuable local commits could get lost forever
• It can generate merge conflicts trying to push older version of branch
• No good audit trail for where the discarded commits went

Resetting should not be treated as an undo button without consequences. Structuring your workflow to avoid needing branch rollbacks is ideal.

Step-by-Step Guide to Replace Local Branch with Remote

With the basics covered, let‘s walk through a practical example of overwriting a local feature branch new-pages by resetting to the origin remote‘s version:

1. Fetch Latest Remote Changes

First we‘ll pull down the latest state of the remote tracking branch origin/new-pages using git fetch:

$ git fetch origin

remote: Counting objects: 75, done.        
remote: Compressing objects: 100% (53/53), done.
remote: Total 62 (delta 27), reused 44 (delta 9)
Unpacking objects: 100% (62/62), done.
From https://github.com/exampleuser/repository
 * [new branch]      new-pages    -> origin/new-pages

This updates our remote bookmarks without impacting local branches.

2. View Local Branches

Before checking out the branch we want to reset, let‘s view our local branches:

$ git branch

  main
* new-pages

We see new-pages is currently checked out.

3. Reset Local Branch to Remote

Now we can directly reset new-pages to our updated origin/new-pages remote bookmark using the --hard flag:

$ git reset --hard origin/new-pages
HEAD is now at 1234abc Latest remote version new-pages

The local new-pages branch and current HEAD now point to origin/new-pages.

4. Confirm Branch Updated

As a check, we can view branches again:

$ git branch

* main
  new-pages

The new-pages branch hash should match origin/new-pages, indicating they reference the same commit.

We successfully updated our local branch to the remote state! But this came at the cost of permanently losing any past local commits.

Comparison to Other Branch Reset Methods

The git reset --hard approach is quite aggressive in overwriting local changes. Developers have a few other options to consider:

Method	Outcome	Destructive?
git reset --hard origin/branch	Full reset local branch to remote state	Yes – wipes commits
git revert other-branch	Undo commits with new "revert" commits	No – preserves history
git checkout new-branch	Changes files to match branch	No – preserves commits

git revert is often the safest way to undo commits by adding a new commit. git checkout swaps file contents without dropping commits.

But for some scenarios, the risks of git reset --hard may be warranted to fully rest a branch.

Troubleshooting Issues with Branch Resets

Fully resetting local branches can produce some confusing issues to debug for newer developers. Here are solutions to common problems:

Merge conflicts when pushing older version of branch

$ git push origin new-pages 
To /repo.git
 ! [rejected]        new-pages -> new-pages (fetch first)
error: failed to push some refs to ‘/repo.git‘
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. 

• Solve by pulling remote changes before pushing your reset branch.

Losing track of where discarded commits went

$ git log
(No old commits show up)

• Use git reflog show new-pages to view previous branch state before reset.
• Or access lost commits by SHA hash directly.

Confusion from ambiguous branch names

Having both a local and remote-tracking branch named new-pages can get confusing. Give them more explicit names like local-pages and origin-pages.

Best Practices for Managing Branches

The most effective way to avoid scrambling to reset branches is by adopting practices to maintain clean branches:

• Rebase frequently – Keep local branch updated by rebasing onto remote often
• Use topic branches – Develop each feature isolated in a topic branch
• Delete stale branches – Prune fully merged or abandoned branches
• Review before merge – Take time to review branch before allowing merge

Following these branch hygiene habits minimizes need for emergency clean up.

FAQs About Resetting Local Branches

Some common questions that arise when resetting branches:

Should I reset master branch to remote?

Generally no. master often tracks origin‘s main production branch, so resetting can pose availability risks.

How do I get back commits after resetting branch?

Check git reflog show <branch> or find lost commit SHAs. But this requires spelunking Git internals.

Will resetting corrupt Git history permanently?

For most intents and purposes, yes. Git does keep loose objects for a time before garbage collecting. But there are no reliable tools to restore original commits.

Is there a way to preview changing to remote branch state?

Yes! Using git checkout -b new-local origin/branch checkout a separate throwaway branch to preview remote state before resetting your real local branch.

Key Takeaways

Resetting local Git branches to match origin should not be taken lightly. Keep these final points in mind:

• Fetch remote changes first – Need an updated remote tracking branch before resetting local to it
• Weigh risks before overwriting – Resetting destroys local commits almost permanently
• Understand alternatives exist – git revert and git checkout can also undo changes
• Structure workflow to avoid requiring branch resets – Plan branches and reviews to minimize surprises

By mastering Git branches, developers can stay sync‘d with team members without having to constantly start branches over.