check_django_migrations.sh

#!/bin/sh
#
# Check if there is a migration conflict in django apps.
# no need for python/django
# drozdowsky & oliwa
#
NEW_MIGRATIONS=$(git diff --name-only origin/master | grep -o ".*/migrations/[0-9]*")
MASTER_MIGRATIONS=$(git ls-tree -r --name-only origin/master | grep ".*/migrations/.*.py")
CURRENT_BRANCH_MIGRATIONS=$(git ls-tree -r --name-only HEAD | grep ".*/migrations/.*.py")

if [ "$MASTER_MIGRATIONS" = "$CURRENT_BRANCH_MIGRATIONS" ]
then
    exit 0
else
    OLD_IFS="$IFS"
    IFS=$'\n'
    for i in $NEW_MIGRATIONS; do
        MIGRATION_PATH=$(dirname "$i")
        MIGRATION=$(echo "$MASTER_MIGRATIONS" | grep "$i")
        if [ -n "$MIGRATION" ]; then
            MIGRATION_NUMBER=$(echo "$i" | grep -o "[1-9][0-9]*$")
            MERGE_NUMBER=$((MIGRATION_NUMBER+1))
            while [ "${#MERGE_NUMBER}" -lt 4 ]; do
                MERGE_NUMBER="0$MERGE_NUMBER"
            done
            echo "$CURRENT_BRANCH_MIGRATIONS" | grep -q "$MIGRATION_PATH/${MERGE_NUMBER}_merge">/dev/null
            if [ $? -eq 0 ]; then
                continue
            fi
            echo "$i - migration with this number already exist at master branch."
            exit 1
        else
            exit 0
        fi
    done
    IFS="$OLD_IFS"
fi