A script to check if branch A has been squash-merged to branch B (default: master) by evaluating diffs of branch A vs diff of all commits on branch B

is_branch_merged.sh

#!/bin/bash

set -e

function cleanup {
  rm $DIFF_FILE $TMPFILE
}

trap cleanup EXIT

if [ $# -lt 1 ]; then
  >&2 echo "Missing branch name"
  exit 1
fi
BRANCH="$1"

echo "Checking for squash-merged branch: ${BRANCH}"

CMP_BRANCH="master"
if [ $# -eq 2 ]; then
  CMP_BRANCH="$2"
fi

DIFF_FILE=$(mktemp)
BASE=$(git merge-base ${BRANCH} ${CMP_BRANCH})
git diff ${BASE}..${BRANCH} > ${DIFF_FILE}
if [ "$(stat -c%s ${DIFF_FILE})" -eq 0 ]; then
  echo "Branch is empty, and can be deleted with: git branch -d ${BRANCH}"
  exit 0
fi
less -S $DIFF_FILE

TMPFILE=$(mktemp)
for commit in $(git log --format='%H' ${BASE}..HEAD | tac -); do
  echo -n "$commit ... "
  git diff ${commit}^..${commit} > $TMPFILE
  LDIFF=$(diff ${TMPFILE} ${DIFF_FILE} | wc -l)
  if [ ${LDIFF} -lt 10 ]; then
    echo "FOUND MERGE COMMIT?"
    echo "-- start of diff --"
    diff -wub ${TMPFILE} ${DIFF_FILE}
    echo "-- end of diff --"
    echo "^c if satisfied. Press any key to continue searching"
    read
  fi
  echo "no match"
done;

echo "NO MATCH FOUND. This branch may not be merged."