Git & Github - Common Issues

Common Problems:

Local vs Remote Histories

Sometimes GitHub already has commits (like an auto-generated README) while your local project has its own commits.
When you try to push, you may see:

![rejected] main -> main (non-fast-forward)
error: failed to push some refs to https://github.com/somegithub/somerepository
Git & Github - Rejected Error.png

This means your local and remote histories diverged..
Git & Github - Separate Timelines.png
Notice that the divergion happened at 'B'.. meaning that the top row is ahead by 'C'

If this happens then:

Solution

Why this happens:
Your local branch and the remote branch have different commits.
Git refuses to overwrite history unless you merge them.

First fetch and allow for unrelated histories: 

git pull origin main --allow-unrelated-histories
  • Resolve any conflicts (e.g., in README.md).
  • Stage and commit the resolution: 
    git add .
git commit -m "some-commit-message-here"
  • Push again: 
    git push origin main

Now what?

Success

YOU DID IT!
Practice creating a repo, adding files, committing, and pushing to GitHub.
Next step: learn branches and pull requests for teamwork!

Common Issues

Beginner Git Problems

  1. “I committed to the wrong branch”
    • Forgetting to create/switch to a feature branch before working.
    • Fix: use git checkout -b early, or git switch -c.
  2. “I deleted files accidentally and Git removed them”
    • Git tracks deletes as well.
    • Fix: restore with git checkout -- filename or git restore filename.
  3. “My files are ignored / not showing up”
    • Usually caused by .gitignore catching them.
  4. Merge conflicts
    • Happens when two people change the same line in a file.
    • Fix: manually edit, then git add and git commit.
  5. “Detached HEAD state”
    • Happens when you checkout a specific commit instead of a branch.
    • Fix: create a new branch from that commit.

Intermediate Git Problems

  1. “Accidentally pushed secrets” (API keys, passwords)
    • Removing them isn’t just deleting — you may need to rewrite history (git filter-repo) or rotate keys.
  2. “I want to undo my last commit”
    • git reset --soft HEAD~1 (keep changes staged)
    • git reset --hard HEAD~1 (discard changes)
  3. Force push mistakes
    • Overwriting remote history by accident (git push --force).
    • Can wipe out teammates’ work.
  4. Cloning into the wrong folder
    • Ending up with nested repos (myrepo/myrepo).
  5. “I can’t pull because I have local changes”
    • Fix: commit or stash before pulling.

Remote / GitHub Problems

  1. Different local vs remote histories (your exact case)
    • Non-fast-forward errors, diverged timelines.
  2. Forgot to set upstream branch
    • First push fails → need git push -u origin main.
  3. Permission denied (publickey)
    • SSH key not set up properly.
  4. Repository not found / 403 error
    • Wrong URL or missing permissions.
  5. Large file rejection
    • GitHub blocks files >100MB. Needs Git LFS or different approach.

Git & GitHub - Documentation

Documentation

Finished

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