Bash script to create a two way diff list of files between 2 git branches. It filters out files from the list which are not present in the current branch.

two-way-diff.sh

#!/bin/bash

cd ${0%/*}

while [[ $# -gt 0 ]]; do
  case "$1" in
    --branch-one=*)
      SOURCE_BRANCH="${1#*=}"
      ;;
    --branch-two=*)
      DESTINATION_BRANCH="${1#*=}"
      ;;
    --output-path=*)
      OUTPUT_PATH="${1#*=}"
      ;;
    --grep-regex=*)
      GREP_REGEX="${1#*=}"
      ;;
    --path-prefix=*)
      PATH_PREFIX="${1#*=}"
      ;;
    *)
      echo "ERROR: invalid arguments, required --branch-one=? --branch-two=? --output-path=?, optional --path-filters=?,?,?.. --path-prefix=? "
      exit 1
  esac
  shift
done

############
# VALIDATE #
############

if [[ -z "${SOURCE_BRANCH}" ]]; then
    echo "ERROR: argument --branch-one=? is required"
    exit 1
fi

if [[ -z "${DESTINATION_BRANCH}" ]]; then
    echo "ERROR: --branch-two=? is required"
    exit 1
fi

if [[ -z "${OUTPUT_PATH}" ]]; then
    echo "ERROR: --output-path=? is required"
    exit 1
fi

if [[ ! -d $(dirname ${OUTPUT_PATH}) ]]; then
    echo "ERROR: --output-path=? $(dirname ${OUTPUT_PATH}) does not exist"
    exit 1
fi

###########
# PREPARE #
###########

TMP_DIR="/tmp/${RANDOM}"
mkdir -p ${TMP_DIR}

OUTPUT="${OUTPUT_PATH}"
SOURCE_TARGET="${TMP_DIR}/source-target.txt"
TARGET_SOURCE="${TMP_DIR}/target-source.txt"
TWO_WAY="${TMP_DIR}/diff-two-way.txt"
DUPLICATES_FILTERED="${TMP_DIR}/duplicates-filtered.txt"

GREP_FILTER=".*"

if [[ ! -z "${GREP_REGEX}" ]]; then
    GREP_FILTER="${GREP_REGEX}"
fi

#####################
# EXTRACT DIFF LIST #
#####################

git fetch

# changes feature-branch against develop
git diff --name-only ${DESTINATION_BRANCH} ${SOURCE_BRANCH} -- \
    | grep -E "${GREP_FILTER}" \
    > ${SOURCE_TARGET}

# changes develop against feature-branch
git diff --name-only ${SOURCE_BRANCH} ${DESTINATION_BRANCH} -- \
    | grep -E "${GREP_FILTER}" \
    > ${TARGET_SOURCE}

cat ${SOURCE_TARGET} > ${TWO_WAY}
cat ${TARGET_SOURCE} >> ${TWO_WAY}

# remove duplicates
awk '!a[$0]++' ${TWO_WAY} > ${DUPLICATES_FILTERED}

# filter files that don't exist in current branch
> ${OUTPUT}
for file in `cat ${DUPLICATES_FILTERED}`
do
    if [[ -f $(pwd)/../../${file} ]]; then
        echo ${file} | awk -v PREFIX="${PATH_PREFIX}" '{print PREFIX$1}' >> ${OUTPUT}
    fi
done

rm -rf ${TMP_DIR}

https://gist.github.com/kickthemooon/6ec1ed9343ea306ab6b0283a8a92f57a#file-two-way-diff-sh-L98

Adjust line 98 to your git repo root directory