gpr

#!/bin/bash
#
# gpr - check out a git pr, preserving prior checkouts if applicable
#
ME=$(basename $0)

red="\e[38;5;196m"
green="\e[38;5;46m"
reset="\e[m"

missing=" argument is missing; see $ME --help for details"
usage="Usage: $ME [--help] [-n | --dry-run] PR

$ME is a friendly, hand-holding front end for 'git pr'.
Feed me a github PR, and I will pull it. My added value is:

  * I will refuse to run if your working directory is dirty

  * If you have a previously checked-out copy of that PR, I will:
    - preserve it as '-revNN'
    - show you instructions on how to diff against that revision.

Requirements:
  1) git-extras, for 'git pr'. This lives in standard Fedora repos.
  2) gh (github cli), from https://cli.github.com/

OPTIONS:

  -n | --dry-run   don't run any commands, just show them
  --help           display usage message
"

die() {
    echo "$ME: $*" >&2
    exit 1
}

verbose=
NOT=
for i
do
    value=`expr "$i" : '[^=]*=\(.*\)'`
    case "$i" in
    -h*|--help)	echo "$usage"; exit 0;;
    -n|--dry-run) NOT=' [NOT!]'; shift ;;
    -v|--verbose) verbose=1; shift;;
    -*)	echo "$ME: unrecognized option $i" >&2
	echo "$usage" >&2
	exit 1;;
    *)	break;;
    esac
done


PR=${1?PR$missing}

test -d .git || die "No .git subdirectory"

#
# Clean branches for merged/closed PRs
#
if [[ $PR = "clean" ]]; then
    # Can only run from main
    current_branch=$(git rev-parse --abbrev-ref=strict HEAD)
    if [[ $current_branch != "main" ]]; then
        die "Please run me from main (current branch: $current_branch)"
    fi

    # Color to use for displaying git commands
    action="\e[37m"
    if [[ -n "$NOT" ]]; then
        action=""
    fi

    previous_branch=
    while read branch; do
        if [[ $branch =~ -rev ]]; then
            if [[ ${branch%-*} = $previous_branch ]]; then
                echo -e " >> ${action}git branch -D \e[33mpr/$branch$NOT$reset"
                if [[ -z "$NOT" ]]; then
                    git branch -D pr/$branch
                fi
            elif [[ -n "$verbose" ]]; then
                echo " [ preserving: $branch ]"
            fi
        else
            pr_info=$(gh pr view $branch)
            title=$(sed -ne 's/^title:\s\+//p' <<<"$pr_info")
            state=$(sed -ne 's/^state:\s\+//p' <<<"$pr_info")

            if [[ $state = "CLOSED" || $state = "MERGED" ]]; then
                printf "%5s ${red}%-6s${reset} %s\n" $branch $state "$title"
                echo -e " >  ${action}git branch -D \e[33mpr/$branch$NOT$reset"
                if [[ -z "$NOT" ]]; then
                    git branch -D pr/$branch
                fi
                previous_branch=$branch
            elif [[ $state != "OPEN" ]]; then
                printf "%5s %-6s %s\n" $branch $state "$title"
            else
                printf "%5s ${green}%-6s${reset} %s\n" $branch $state "$title"
            fi
        fi
    done < <(git branch --list --format '%(refname:short)' | sed -ne 's;^pr/;;p')
    exit 0
fi

# Default case: called with an actual PR.
#
# Abort if there are modified files
modified=$(git status --porcelain --untracked-files=no)
if [[ -n "$modified" ]]; then
    echo "$modified"
    echo
    die "This only works on clean directories"
fi

newrev=1
latest_backup=
while read branch; do
    rev=$(expr "$branch" : ".*-rev0*\([0-9]\+\)" 2>/dev/null)
    if [[ -n "$rev" ]]; then
        # Keep existing -revXX branches as they are, but keep track of
        # the highest local iteration, so we can rename our current
        # branch to that-plus-one.
        if (( rev >= newrev )); then
            newrev=$((rev + 1))
        fi
    else
        latest_backup="pr/$PR-rev$(printf %02d $newrev)"
        cmd="git branch -m $branch $latest_backup"
        echo $cmd$NOT
        if [[ -z "$NOT" ]]; then
            $cmd
        fi
    fi
done < <(git branch --format '%(refname:short)'| grep pr/$PR | tac)

cmd="git pr $PR upstream"
echo $cmd$NOT
if [[ -z "$NOT" ]]; then
    $cmd

    # FIXME: nope, this doesn't work; we need to track all 'branch -m's
    if [[ -n $latest_backup ]]; then
        echo "  git range-diff --creation-factor=50 ${latest_backup}...pr/$PR"
    fi
fi