Get next version tag of a Git repo considering a version constraint

next_tag_by_version_constraint.sh

#!/usr/bin/env bash

# # # # # # # # # # # # # # # # # # # #
# Compare two versions
# https://stackoverflow.com/a/4025065
#
# Arguments:
#   VERSION_1
#   VERSION_2
# Returns:
#   0 =
#   1 >
#   2 <
# # # # # # # # # # # # # # # # # # # #
compare_versions() {
    [[ $1 == $2 ]] && return 0

    local IFS=.
    local i ver1=($1) ver2=($2)

    # fill empty fields in ver1 with zeros
    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++)); do
        ver1[i]=0
    done

    for ((i=0; i<${#ver1[@]}; i++)); do
        if [[ -z ${ver2[i]} ]]; then
            # fill empty fields in ver2 with zeros
            ver2[i]=0
        fi

        if ((10#${ver1[i]} > 10#${ver2[i]})); then
            return 1
        fi

        if ((10#${ver1[i]} < 10#${ver2[i]})); then
            return 2
        fi
    done

    return 0
}

#######################################
# Get the next latest tag
#
# Arguments:
#   REPO_URL
#   VERSION_CONSTRAINT
#######################################
next_tag() {
    local CURRENT=$(echo "$2" | sed -E 's/(\*\.)?\*/0/g')
    local REPO_URL=$(get_repo_url $1)

    # allow last minor version to go up
    # 1.3.1   >= 1.3.1   < 1.4.0
    # 1.3     >= 1.3     < 2.0.0
    local MAX_VERSION=$(echo "$CURRENT" \
        | awk -F. '{ major=$1+1; minor="0"; patch=""; if ( $3 || $3 == 0 ) { major=$1; minor=$2+1; patch=".0"; } print major"."minor""patch; }')
    local SORTED_TAGS=$(git ls-remote --tags $REPO_URL \
        | grep -o "0\.\d*\.*\d*$" \
        | sort -t '.' -k 1,1 -k 2,2 -k 3,3 -g)

    #echo "CURRENT: $CURRENT"
    #echo "MAX_VERSION: $MAX_VERSION"

    while read -r TAG; do
        GIT_TAG=$TAG
        compare_versions $CURRENT $TAG
        OP=$?

        # TAG is an older version
        [[ $OP -eq 2 ]] || continue

        compare_versions $TAG $MAX_VERSION
        OP=$?

        # stop search if TAG is greater than MAX_VERSION
        [ $OP -eq 1 ] && break

        NEXT_VERSION=$TAG
    done <<< "$SORTED_TAGS"

    echo ${NEXT_VERSION:-$GIT_TAG}
}