List open GitHub PR branches for merging

git-incoming

#!/bin/bash

#
# This script finds incoming PR branches from a GitHub based remote.
#
# Example
#
# $ git checkout -b incoming origin/master
# $ git incoming origin | xargs git merge
#

if [ $# != 1 ]; then
    >&2 echo "Usage: git incoming <remote>"
    exit 1
fi

remote="${1}"
fetch_refs="+refs/pull/*/head:refs/remotes/${remote}/pr/*"

function configure() {
    # Check if already configured.
    git config -l | grep -Fq "remote.${remote}.fetch=${fetch_refs}"
    if [ $? -eq 0 ]; then
        return
    fi
    git config --add "remote.${remote}.fetch" "${fetch_refs}"
}

function owner_repo() {
    # FIXME: Handle case where this does not match.
    git config "remote.${remote}.url" | sed -n 's|^git@github.com:\(.*\)\.git$|\1|p'
}

function gh_get() {
    curl --show-error --silent \
         -H "Authorization: token ${GITHUB_API_TOKEN}" \
         --url "https://api.github.com/${1}"
}

function open_prs() {
    gh_get "repos/$(owner_repo)/pulls?state=open&sort=updated&direction=desc&base=master" | jq '.[] | .number'
}

# Ensure PR branches are available.
configure
git fetch origin -q --prune

# For each open PR, print the remote branch name.
open_prs | while read line; do echo "${remote}/pr/${line}"; done

This is just a clumsy utility to help me with a common operation. Namely: create a branch that works on the merged results of open PRs.