find_todos.sh

#!/usr/bin/env bash

todo='0'

echo "[" > todo_data.json

git log --reverse --oneline |
while IFS= read -r commit
do
    hash=$(echo $commit | cut -d' ' -f1)
    adds=$(git diff $hash~ $hash | grep '^\+' | grep 'TODO' | wc -l | xargs)
    solv=$(git diff $hash~ $hash | grep '^\-' | grep 'TODO' | wc -l | xargs)

    todo=$((todo + adds))
    todo=$((todo - solv))

    if [[ "$adds" != "0" ]] || [[ "$solv" != "0" ]]
    then
        date=$(git show -s --format=%ci $hash)
        echo "[\"$date\", \"$hash\", $adds, $solv]," >> todo_data.json
        echo "$hash: there are now $todo TODOs. added $adds, removed $solv"
    fi
done

echo "]" >> todo_data.json