git-submodules-status

#!/bin/bash
#
# Boost Software License 1.0 (https://www.boost.org/LICENSE_1_0.txt)
# Copyright (c) 2016-2018 dunnhumby Germany GmbH.
# All rights reserved.

################################################################################
#
#   Description:
#   ------------
#       Fetches all submodules from their respective remote repositories, and
#       shows a table that lists for each submodule : the latest available
#       version, the current version and a small visual cue to easily identify
#       mismatches between the two.
#
#   Usage:
#   ------
#   (first place this script in one of the directories in $PATH)
#       $> cd path/to/repo
#       $> git submodules-status
#
################################################################################

appendSpaces()
{
    INITIAL_STR=${1}
    TARGET_LENGTH=${2}

    SPACES_TO_APPEND=$((TARGET_LENGTH - ${#INITIAL_STR}))

    echo -n ${INITIAL_STR}
    for ((i = 0; i < ${SPACES_TO_APPEND}; i++))
    do
        echo -n " "
    done
    echo ""
}

# Confirm that we are in a git repository
GIT_TOP=$(git rev-parse --show-toplevel) || exit $?

# Check if the project has any submodules in the first place
if ! [ -a "${GIT_TOP}/.gitmodules" ]; then
    PROJECT_NAME=$(basename ${GIT_TOP})
    echo "Project '${PROJECT_NAME}' has no submodules. Nothing to do here!"
    exit 0
fi

# Save the present working directory as we'll be changing directories
# (potentially several times)
ORIG_DIR=${PWD}

# cd to the top-level git directory so that submodule paths are relative to it
cd ${GIT_TOP}

# Confirm that all the submodules have been initialised
UNINITIALISED_SUBMODS=(`git submodule status | grep "^-" | awk -F"/" '{print $NF}'`)
if [ ${#UNINITIALISED_SUBMODS[@]} -gt 0 ]; then
    echo "The following submodules haven't been initialized : ${UNINITIALISED_SUBMODS[@]}"
    echo "Try running this first:"
    echo "    git submodule update --init"
    exit 2
fi

# Read the existing submodules information into an array. After this, the array
# should contain an even number of entries, with each pair of entries containing
# the path of the submodule (relative to the top-level git directory) and the
# current submodule version (within parentheses) respectively.
SUBMODS_INFO_ARR=(`git submodule status | sed 's/^\s\+//g' | cut -d" " -f2-`)

# Fetch each submodule from the remote repo so that we can get its latest tag
git submodule foreach git remote update
echo ""

# Get the length of the longest submodule name
MAX_LEN=9 # Initialize to length of the header string "Submodule"
for ((i = 0; i < ${#SUBMODS_INFO_ARR[@]}; i+=2))
do
    SUBMOD_PATH=${SUBMODS_INFO_ARR[$i]}

    SUBMOD_NAME=$(echo ${SUBMOD_PATH} | rev | cut -d"/" -f1 | rev)
    SUBMOD_NAME_LEN=${#SUBMOD_NAME}

    if [ ${SUBMOD_NAME_LEN} -gt ${MAX_LEN} ]
    then
        MAX_LEN=${SUBMOD_NAME_LEN}
    fi
done

FIRST_COLUMN_WIDTH=$((${MAX_LEN}+4))

# For now, the width of the second column is hard-coded to 19
# i.e. length of the string "Current version" + 4
SECOND_COLUMN_WIDTH=19

# Also, the width of the third column is hard-coded to 12
# i.e. length of the string "Latest version" - 2
# so that the '✗' which indicates a difference between the two versions can
# appear as the last character of the "Latest version" column
THIRD_COLUMN_WIDTH=12

# Write the header row and its underlines
echo "$(appendSpaces "Submodule" ${FIRST_COLUMN_WIDTH}) Current version     Latest version"
echo "---------     ---------------     --------------"

# Write each submodule's data
for ((i = 0; i < ${#SUBMODS_INFO_ARR[@]}; i+=2))
do
    SUBMOD_PATH=${SUBMODS_INFO_ARR[$i]}
    SUBMOD_VERSION=$(echo ${SUBMODS_INFO_ARR[$i+1]} | sed 's/^(\(.*\))$/\1/g')

    SUBMOD_NAME=$(echo ${SUBMOD_PATH} | rev | cut -d"/" -f1 | rev)
    SUBMOD_FULL_PATH="${GIT_TOP}/${SUBMOD_PATH}"

    cd ${SUBMOD_FULL_PATH}

    LATEST_TAG=$(git tag --list "v*" --sort=v:refname | tail -1)

    MISMATCH_CHARACTER=$([ "${SUBMOD_VERSION}" = "${LATEST_TAG}" ] && echo " " || echo "✗")

    echo "$(appendSpaces ${SUBMOD_NAME} ${FIRST_COLUMN_WIDTH}) $(appendSpaces ${SUBMOD_VERSION} ${SECOND_COLUMN_WIDTH}) $(appendSpaces ${LATEST_TAG} ${THIRD_COLUMN_WIDTH}) ${MISMATCH_CHARACTER}"
done

# Go back to the original directory from where the script was run
cd ${ORIG_DIR}