Applies PRs to any repository. Place into ~/.local/bin and run in the target git directory

pr_apply.sh

#!/usr/bin/env bash

remote="upstream"
url=$(LANG=C git remote -v get-url $remote 2>&1)

if [[ "$url" == fatal* || "$url" == error* ]]; then
	remote="origin"
	url=$(LANG=C git remote -v get-url $remote 2>&1)
fi
if [[ "$url" == fatal* || "$url" == error* ]]; then
	echo "Can neither find 'upstream' nor 'origin' git remote."
	exit 1
fi
if [[ "$url" =~ git@.+\.git ]]; then
	# Replace SSH URI with HTTPS
	# SSH: ssh://git@gitservice.tld:foo/bar.git
	url="${url#ssh://}"
	url="${url#git@}"
	url="https://${url/:/\/}" # replace ':' with '/'
fi
url="${url%.git}" # trim tailing ".git"

# GitHub:   USER/REPO/pull/NUMBER.patch
# Forgejo:  USER/REPO/pulls/NUMBER.patch
p_pull="pulls"
[[ "$url" == *github.com* ]] && p_pull="pull"

set -e
case "$2" in
	"")
		url="$url/$p_pull/$1.patch"
		curl -Ls "$url" | git am -3 --ignore-space-change -
		;;
	"diff")
		url="$url/$p_pull/$1.diff"
		curl -Ls "$url" | git apply -
		;;
	"merge")
		git fetch "$remote" "pull/$1/head" && git merge --no-edit FETCH_HEAD
		;;
	*)
		echo "Invalid usage. Examples:"
		echo "  pr_apply 123       # Apply patch"
		echo "  pr_apply 123 merge # Quick merge"
		echo "  pr_apply 123 diff  # Apply diff"
		exit 1
		;;
esac

if [ $? -ne 0 ]; then
	exit 1
fi