It seems that the most recent git timestamp is always the current time

Hi! My project needs to use git timestamp, but I noticed that using the command "git log -1 --format=%at filepath" in a github action always gets the current timestamp. But it seemed to be working fine a few months ago.

name: test

on:
  push:
    branches:
      - dev

jobs:
  build-deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - run: git log -1 --format=%at setup.py

Then I get this.

It's current timestamp.

How can I get a correct git timestamp?

Start with the provided GitHub Actions workflow and reproduce the output of git log -1 --format=%at setup.py after actions/checkout@v2. Check the checkout step and the repository history available to the workflow, then verify that the command reports the intended timestamp rather than the current time.