git pre-receive hook declined

3 min read 18-12-2024

Git pre-receive hooks are powerful tools that allow you to enforce policies and perform checks before accepting pushed commits to your repository. However, encountering a "pre-receive hook declined" message can be frustrating. This article will delve into the causes of this error, provide troubleshooting steps, and offer solutions to get your code smoothly into the repository.

Understanding the Pre-Receive Hook

The pre-receive hook is a script executed on the server-side of a Git repository before any pushed commits are accepted. It receives a list of references (branches, tags) being updated. If the hook script exits with a non-zero status code, the push is rejected. This allows administrators to implement various checks, such as:

Preventing pushes to protected branches: This is common for main or master branches, ensuring only authorized individuals or processes can modify them.
Enforcing coding standards: The hook can check for code style violations using linters like ESLint or Pylint.
Verifying commit messages: The hook might enforce a specific commit message format or reject messages containing certain keywords.
Running automated tests: Before accepting changes, the hook can run automated tests to ensure the code still functions correctly.
Restricting file types or changes: This could prevent accidental commits of sensitive files or large binary files.

Common Reasons for Pre-Receive Hook Rejection

The "pre-receive hook declined" message is a general error; the specific reason is usually logged on the server. However, some frequent culprits include:

1. Server-Side Issues:

Permissions: The pre-receive hook script might lack the necessary execution permissions. Check the file permissions (using chmod +x pre-receive) to ensure it's executable.
Hook Script Errors: Syntax errors, logic flaws, or unhandled exceptions within the hook script itself can cause it to fail. Carefully review the script's logs for error messages. These logs are usually found in the same directory as the pre-receive hook file, or in the server's error logs.
Server Resource Constraints: If the hook performs computationally intensive tasks, the server might run out of resources (memory, CPU), causing the script to fail.

2. Client-Side Issues (Less Common):

Network Problems: Intermittent network connectivity between the client and the server can prevent the push from completing successfully, leading to a seemingly arbitrary rejection.
Incorrect Git Configuration: While less likely, an incorrectly configured Git client on your local machine could contribute to the issue. Double-check your remote repository URL and credentials.

Troubleshooting Steps

Check Server Logs: The most crucial step is examining the server-side logs. This will pinpoint the exact reason for the rejection. The location of these logs varies depending on the server setup, but it's often near the .git/hooks directory of the repository.
Verify Hook Script: Carefully review the pre-receive hook script for syntax errors, logical flaws, or any unhandled exceptions. Test the script independently if possible, simulating the input it receives during a push.
Check File Permissions: Use ls -l .git/hooks/pre-receive to verify the hook script has executable permissions (-rwxr-xr-x). If not, use chmod +x .git/hooks/pre-receive to grant execute permissions.
Simplify the Hook (Temporarily): To isolate the problem, temporarily replace the hook script with a simpler version that always exits with a zero status code (accepting all pushes). This helps determine if the problem originates from the hook itself or another factor. Remember to revert this change after troubleshooting.
Inspect Server Resources: If the hook performs intensive tasks, monitor server resources (CPU, memory) during a push attempt to see if resource exhaustion is the cause.
Network Connectivity: Rule out network connectivity issues by checking your internet connection and attempting other network operations.
Repository Cleanup: In rare cases, corruption within the Git repository itself might cause issues. A repository cleanup might resolve this, though this should be done cautiously and ideally after creating a backup.

Example Pre-Receive Hook (Preventing Pushes to Main)

This example hook prevents pushes to the main branch unless the user is specifically authorized (replace "authorized_user" with the actual username).

#!/bin/bash

while read oldrev newrev refname
do
  if [[ "$refname" == "refs/heads/main" ]]; then
    user=$(git config user.name)
    if [[ "$user" != "authorized_user" ]]; then
      echo "Pushing to main is restricted to authorized_user." >&2
      exit 1
    fi
  fi
done
exit 0

Remember to make this script executable using chmod +x pre-receive.

By systematically following these troubleshooting steps and understanding the potential causes, you can effectively diagnose and resolve the "pre-receive hook declined" error, ensuring smooth code integration into your Git repository. Remember to always prioritize securing your repository and implementing robust checks to maintain code quality and integrity.