OGG… I cannot push to remote branch and cannot pull the remote changes…

git branch
Author

Ryo Nakagami

Published

2024-07-18

Modified

2024-07-26

Problem

Let’s say you are working on a local development branch, eda/data-sanity-check. After some modifications and commits on the local, you realized that you cannot push to the remote branch.

When you hit git push, you’ve got the following error:

% git push
...
To https://github.com/RyoNakagami/github_sandbox
 ! [rejected]        eda/data-sanity-check -> eda/data-sanity-check (fetch first)
error: failed to push some refs to 'https://github.com/RyoNakagami/github_sandbox'
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. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

What is happening

Generally speaking, you need to pull the remote and stay up-to-date before pushing. But the problem is you’ve already git commited on some modifications at the current branch while there are some commits at the remote branch too, and that’s why you cannot pull the remote because of the history conflict.

%%{init: { 'logLevel': 'debug', 'theme': 'base', 
            'gitGraph': {'rotateCommitLabel': true,
                         'mainBranchName': 'local'}}}%%
    gitGraph
       commit id: "local-mod-1"
       branch remote
       commit id: "remote-mod-1"
       checkout local
       commit id: "local-mod-2"
       commit id: "local-mod-3"
       checkout remote
       merge local id:"❗️failed to push"

Fig 1. Conflict between the local and the remote

%%{init: { 'logLevel': 'debug', 'theme': 'base', 
            'gitGraph': {'rotateCommitLabel': true,
                         'mainBranchName': 'local'}}}%%
    gitGraph
       commit id: "local-mod-1"
       branch remote
       commit id: "remote-mod-1"
       checkout local
       commit id: "local-mod-2"
       commit id: "local-mod-3"
       merge remote id:"❗️failed to pull"

Fig 2. You cannot pull the remote either

Solution: git pull --rebase

▶  Steps

  1. Check the difference between the local and the romote
  2. Resolve the local-remote conflict
  3. push top the remote after solving the conflict

▶  Commands

## fetch the remote info
% git fetch

## check which files are different from the remote
% git difftool eda/data-sanity-check origin

The above commands are just for checking the remote-local difference. If you want to solve the problem quickly, it’s alright to skip the process.

Then, let’s solve the conflict.

## Step 2
% git pull --rebase
...
Auto-merging eda/check_datasanity.py
CONFLICT (content): Merge conflict in eda/check_datasanity.py
error: could not apply <your-current HEAD commit-id>... eda: add histogram
hint: Resolve all conflicts manually, mark them as resolved with
hint: "git add/rm <conflicted_files>", then run "git rebase --continue".
hint: You can instead skip this commit: run "git rebase --skip".
hint: To abort and get back to the state before "git rebase", run "git rebase --abort".
Could not apply <your-current HEAD commit-id>... eda: add histogram

## after resolving the conflict
% git rebase --continue

The git pull --rebase commands is the same as git pull + git rebase. Aftrer hitting git pull --rebase, you are now in the conflict-resolution process when there is a conflict. You need to open the files which cause the conflict and fix them manually as you do in a usual merge-conflict.

After resolving the conflict, do not foregt to run git rebase --continue, otherwise you continue to stay in the conflict-resolution mode.

Your git history will look like the following;

%%{init: { 'logLevel': 'debug', 'theme': 'base', 
            'gitGraph': {'rotateCommitLabel': true,
                         'mainBranchName': 'local'}}}%%
    gitGraph
       commit id: "local-mod-1"
       branch remote
       commit id: "remote-mod-1"
       checkout local
       merge remote id:"pull"
       commit id: "conflict-resolve"

Fig 3. git pull –rebase

At the above conflict-resolve node, you choose which local modifications should stay in the repository history.

Then, now that you are able to push to the remote.

## Step 3: push to the remote
% git push origin HEAD

▶  REMARKS

  • When hitting git pull --rebase, it’s possible that all differences automatically are resoloved.
    • For example, you modified some files but ther remote changes are not related to the files you’ve chnaged.
    • git pull --rebase automatically resolved the difference which does not cause the conflict.
  • When you get confused and want to get out of the conflict-resolution mode without saving, hit the git rebase --abort