CODEWITHSUNDEEP
gitbashgit-branchgithooks
listenlight
listenlight

Reputation: 662

Git hook to get prior branch name

I'm working on .git/hooks/post-checkout and having trouble either sourcing/exporting the branch name, or getting the prior branch name. I want to restart the server when switching to or from s3 branch.

I couldn't figure out how to source the env var in bash, so I tried using git to get the prior branch, but the closest I got was git checkout -/git checkout @{-1}, tho I'm not sure simply how to retrieve the prior branch name without the call to checkout.

Should I be using Git env vars instead of shell?

Current file just restarts the server on each checkout

#!/bin/bash

touch tmp/restart.txt
echo " *** restarting puma-dev"

current_branch=$(git branch | sed -n -e 's/^\* \(.*\)/\1/p')
if [ "$current_branch" = "s3" ]
then
  echo " *** please don't upload any files"
  echo
fi

Upvotes: 0

Views: 579

Answers (3)

Chris
Chris

Reputation: 471

Git passes the previous and current ref names to the post-checkout hook, so you should be able to do something like:

#!/bin/sh

oldref="$1"
newref="$2"
branch_update="$3"

[ "$branch_update" = '1' ] || exit  # exit if branch didn't change

[ "$oldref" = 'refs/heads/s3' ] && oldref_was_s3=1
[ "$newref" = 'refs/heads/s3' ] && newref_is_s3=1

if [ -z "$oldref_was_s3" -a -n "$newref_is_s3" ]; then
    echo " *** please don't upload any files"
fi

Totally untested, but it should be close.

Upvotes: 2

listenlight
listenlight

Reputation: 662

Thanks in part to Chris, whose method I couldn't interpret or get working, but found the information helpful, and thanks to Keif Kraken, whose method I did get working.

Restart server when changing to or from a specific branch (s3)

.git/hooks/post-checkout script

#!/bin/bash
oldref=$(git rev-parse --abbrev-ref @{-1})
newref=$(git rev-parse --abbrev-ref head)

if [[ ( "$oldref" = "s3" || "$newref" = "s3" ) && "$oldref" != "$newref" ]]
then
  touch tmp/restart.txt
  echo " *** restarting puma-dev"
  echo " *** please don't upload any files"
fi

Upvotes: 0

Keif Kraken
Keif Kraken

Reputation: 10640

You should be able to use this line to grab the previous branch name:

git rev-parse --abbrev-ref @{-1}

and to get the current branch name:

git rev-parse --abbrev-ref HEAD

Upvotes: 1

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