Git push: fatal: the remote end hung up unexpectedly

Everthing was working as expected when I closed my laptop yesterday and today morning when I try running mkdocs gh-deploy. I see the below error

Error

Enumerating objects: 101, done.
Counting objects: 100% (101/101), done.
Delta compression using up to 16 threads
Compressing objects: 100% (32/32), done.
send-pack: unexpected disconnect while reading sideband packet
Writing objects: 100% (54/54), 1.30 MiB | 1.73 MiB/s, done.
Total 54 (delta 23), reused 0 (delta 0), pack-reused 0
fatal: the remote end hung up unexpectedly
Everything up-to-date
Traceback (most recent call last):
  File "/Users/vmac/.pyenv/versions/3.9.13/bin/mkdocs", line 8, in <module>
    sys.exit(cli())
  File "/Users/vmac/.pyenv/versions/3.9.13/lib/python3.9/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
  File "/Users/vmac/.pyenv/versions/3.9.13/lib/python3.9/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
  File "/Users/vmac/.pyenv/versions/3.9.13/lib/python3.9/site-packages/click/core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/Users/vmac/.pyenv/versions/3.9.13/lib/python3.9/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Users/vmac/.pyenv/versions/3.9.13/lib/python3.9/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
  File "/Users/vmac/.pyenv/versions/3.9.13/lib/python3.9/site-packages/mkdocs/__main__.py", line 318, in gh_deploy_command
    gh_deploy.gh_deploy(
  File "/Users/vmac/.pyenv/versions/3.9.13/lib/python3.9/site-packages/mkdocs/commands/gh_deploy.py", line 129, in gh_deploy
    ghp_import.ghp_import(
  File "/Users/vmac/.pyenv/versions/3.9.13/lib/python3.9/site-packages/ghp_import.py", line 285, in ghp_import
    git.check_call('push', opts['remote'], opts['branch'])
  File "/Users/vmac/.pyenv/versions/3.9.13/lib/python3.9/site-packages/ghp_import.py", line 119, in check_call
    sp.check_call(['git'] + list(args), **kwargs)
  File "/Users/vmac/.pyenv/versions/3.9.13/lib/python3.9/subprocess.py", line 373, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['git', 'push', 'origin', 'gh-pages']' returned non-zero exit status 1.

What is this error?

The error message "fatal: The remote end hung up unexpectedly" typically occurs during a Git operation when the server unexpectedly terminates the connection. This issue is often related to the size of the data being pushed or network-related problems. Here are some common causes and solutions:

Common Causes

1. Large File Size: The most frequent reason for this error is that the size of the files being pushed exceeds the server's configured limits. This can happen if the repository contains large files or if you're trying to push a large number of changes at once.

2. Network Issues: High-latency networks or unstable connections can lead to this error, especially if the connection drops during the data transfer.

3. Proxy Server Configuration: If you're behind a proxy, it may not support the chunked transfer encoding used by Git, leading to connection issues.

Solutions

1. Increase the Git Buffer Size: You can increase the buffer size to accommodate larger files. Run the following commands in your terminal:

For HTTP:

   git config --global http.postBuffer 524288000

For SSH:

   git config --global ssh.postBuffer 524288000

You may adjust the buffer size up to 2 GB if necessary.

1. Check Proxy Settings: If you're using a proxy, try bypassing it or adjusting the proxy settings. You can push directly to the server's IP address and port to see if that resolves the issue.

2. Reduce the Size of the Push: If possible, try breaking down your push into smaller commits. This can help avoid exceeding the server limits.

3. Network Stability: Ensure your internet connection is stable. If you're on a high-latency network, consider using a more reliable connection.

4. Server Configuration: If you have control over the server, check the server's configuration to ensure it allows for larger file uploads. This may involve adjusting settings like client_max_body_size in Nginx or similar configurations in other web servers.

By following these steps, you should be able to resolve the "fatal: The remote end hung up unexpectedly" error and successfully push your changes to the remote repository.

Additional configurations

If setting the http.postBuffer configuration alone doesn't work, try the additional commands

git config http.postBuffer 524288000
git config http.lowSpeedTime 600
git config --global pack.window 1
git config --global core.compression 0

http.postBuffer

Maximum size in bytes of the buffer used by smart HTTP transports when POSTing data to the remote system. For requests larger than this buffer size, HTTP/1.1 and Transfer-Encoding: chunked is used to avoid creating a massive pack file locally. Default is 1 MiB, which is sufficient for most requests.

For other git-config options check the documentation here