show_rubocop_todo_line_number_changes.py

import matplotlib.pyplot as plt
import subprocess
import datetime

raw = (
    subprocess.Popen(
        'git log --pretty=" %at, %h" --reverse --after "2020/01/01" .rubocop_todo.yml',
        shell=True,
        stdout=subprocess.PIPE,
    )
    .stdout.read()
    .decode()
)


x = []
y = []

lines = raw.splitlines()
lines.sort()
for l in lines:
    unixtime, sha = l.split(",")

    date = datetime.datetime.fromtimestamp(int(unixtime))

    length = (
        subprocess.Popen(
            f"git cat-file -p {sha}:.rubocop_todo.yml | wc -l",
            shell=True,
            stdout=subprocess.PIPE,
        )
        .stdout.read()
        .decode()
    ).strip()

    x.append(date)
    y.append(int(length))

fig = plt.figure()
ax = fig.add_subplot(1, 1, 1, ylim=(0, max(y) + 100))
plt.xticks(rotation=90)

ax.plot(x, y)
plt.tight_layout()
plt.legend()
plt.show()