Git pre-push hook to prevent force pushing the master/main branch.

install-pre-push.sh

#!/bin/bash
# This script will install a Git pre-push hook that prevents force pushing the master/main branch.
# There are three variants that I have built:
# - pre-push: prevents force-pushing to master/main.
# - pre-push-2: prevents force-pushing to master/main depending on the remote (you need to edit the file!).
# - pre-push-3: prevents any type of pushing to master/main.
# Set the desired version like this before proceeding:
# FILE=pre-push

# Single repo installation:
# curl -fL https://gist.githubusercontent.com/stefansundin/d465f1e331fc5c632088/raw/install-pre-push.sh | sh -s ${FILE:-pre-push}
# Uninstall:
# rm .git/hooks/pre-push

# Global installation instructions:
# mkdir $HOME/.githooks
# git config --global core.hooksPath $HOME/.githooks
# curl -fL -o $HOME/.githooks/pre-push https://gist.githubusercontent.com/stefansundin/d465f1e331fc5c632088/raw/${FILE:-pre-push}
# chmod +x $HOME/.githooks/pre-push
# Uninstall:
# rm $HOME/.githooks/pre-push

GIT_DIR=`git rev-parse --git-common-dir 2> /dev/null`

echo
echo

if [ "$GIT_DIR" == "" ]; then
	echo This does not appear to be a git repo.
	exit 1
fi

if [ -f "$GIT_DIR/hooks/pre-push" ]; then
	echo There is already a pre-push hook installed. Delete it first.
	echo
	echo "    rm '$GIT_DIR/hooks/pre-push'"
	echo
	exit 2
fi

FILE=${1:-pre-push}

echo "Downloading $FILE hook from https://gist.github.com/stefansundin/d465f1e331fc5c632088"
echo

curl -fL -o "$GIT_DIR/hooks/pre-push" "https://gist.githubusercontent.com/stefansundin/d465f1e331fc5c632088/raw/$FILE"
if [ ! -f "$GIT_DIR/hooks/pre-push" ]; then
	echo Error downloading pre-push script!
	exit 3
fi

chmod +x "$GIT_DIR/hooks/pre-push"

echo "You're all set!"
echo "P.S. There is now a way to install this globally, see the instructions on the gist page."

exit 0

pre-push

#!/bin/bash
# Prevents force-pushing to master/main.
# Install:
# cd path/to/git/repo
# curl -fL -o .git/hooks/pre-push https://gist.githubusercontent.com/stefansundin/d465f1e331fc5c632088/raw/pre-push
# chmod +x .git/hooks/pre-push

BRANCH=`git rev-parse --abbrev-ref HEAD`
PUSH_COMMAND=`ps -ocommand= -p $PPID`

if [[ "$BRANCH" =~ ^(master|main)$ && "$PUSH_COMMAND" =~ force|delete|-f ]]; then
  echo
  echo "Prevented force-push to $BRANCH. This is a very dangerous command."
  echo "If you really want to do this, use --no-verify to bypass this pre-push hook."
  echo
  exit 1
fi

exit 0

pre-push-2

#!/bin/bash
# Use this file to prevent force pushes only to specific remotes (e.g. work).
# You have to customize it below ("workorg/").
# Prevents force-pushing to master.
# Install:
# cd path/to/git/repo
# curl -fL -o .git/hooks/pre-push https://gist.githubusercontent.com/stefansundin/d465f1e331fc5c632088/raw/pre-push-2
# chmod +x .git/hooks/pre-push

ORIGIN="$1"
REMOTE_URL="$2"

BRANCH=`git rev-parse --abbrev-ref HEAD`
PUSH_COMMAND=`ps -ocommand= -p $PPID`

if [[ "$BRANCH" =~ ^(master|main)$ && "$PUSH_COMMAND" =~ force|delete|-f && "$REMOTE_URL" == *"workorg/"* ]]; then
  echo
  echo "Prevented force-push to $BRANCH. This is a very dangerous command."
  echo "If you really want to do this, use --no-verify to bypass this pre-push hook."
  echo
  exit 1
fi

exit 0

pre-push-3

#!/bin/bash
# Prevents any type of pushing to master/main.
# Install:
# cd path/to/git/repo
# curl -fL -o .git/hooks/pre-push https://gist.githubusercontent.com/stefansundin/d465f1e331fc5c632088/raw/pre-push
# chmod +x .git/hooks/pre-push

BRANCH=`git rev-parse --abbrev-ref HEAD`

if [[ "$BRANCH" =~ ^(master|main)$ ]]; then
  echo
  echo "Prevented push to $BRANCH."
  echo "If you really want to do this, use --no-verify to bypass this pre-push hook."
  echo
  exit 1
fi

exit 0

Thanks

Nice. You reference this page in the file itself. Handy.

thanks for this!

I changed the $PUSH_COMMAND comparison to =~ force|delete|-f|"+master" to prevent git push origin +master

is there a way to have this hook available on a new clone of the repository ? so basically it is somehow installed on the server and then gets installed on the client side with a clone. the idea being to stop accidental checkin to master for e.g.

@rajah1313 Not from the server to a client, but you can change your default git hooks that are created when you clone a repository, and include this hook there. See this thread for details: http://stackoverflow.com/questions/1977610/change-default-git-hooks

If you have control over the server, you can install a git hook there to prevent force pushes etc. GitHub also has protected branches these days, which didn't exist when I created this.

I just updated the instructions above to include instructions for a global installation using the core.hooksPath configuration option introduced in Git 2.9. Update to that and you no longer have to install this in every git repository, just do it once.

I ran the global installation as user a, but I could still commit master of a repo owned by user a with no errors.
I suppose this blocks only push?

@bilogic Yes. For a pre-commit hook see https://gist.github.com/stefansundin/9059706.

I also no longer use the global install myself so I do not recommend it.

@stefansundin i see thanks.

Here's what I understood:

1. I have origin at /repository/origin
2. I check out master to /repository/local
3. This pre-push hook must exists at /repository/local/.git/hooks to have the desired effect
4. But seems to me that it can also be removed by the person in control of /repository/local
5. Is there a way to prevent a push from /repository/local into /repository/origin's master, controlled by the origin?

@bilogic Correct, this hook is all local. GitHub has support for protected branches now, which you can use to prevent pushes to certain branches (they didn't have this feature back when I wrote this). https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/defining-the-mergeability-of-pull-requests/about-protected-branches

@stefansundin I wanted to prevent a push without GitHub. Anyway, thanks!

@bilogic You probably want a pre-receive hook if you have control over the server. I don't have a script ready for you so you are on your own. 😆

It would really have accelerated things if you posted more information up-front, but I guess we finally arrived at the solution. 😅

Good luck!