无效的"requirements_file"：路径docs/requirements.txt不存在

Question

在使用ReadTheDocs更新我的项目文档时，我没有突然开始收到这个错误：

Problem parsing YAML configuration. Invalid "requirements_file": path docs/requirements.txt does not exist

奇怪的是，肯定有一个docs/requirements.txt文件，而且，在通过RTD构建的提交和开始失败的提交之间，我甚至没有接触过它。

究竟是什么原因导致的错误似乎不在日志中：

Read the Docs build information
Build id: 7495313
Project: squiggle
Version: latest
Commit: 68b4ea3a22d740fce1bfdd5bd5af75ccf0cd5367
Date: 2018-07-16T17:54:43.712130
State: finished
Success: False


[rtd-command-info] start-time: 2018-07-16T23:19:18.575436, end-time: 2018-07-16T23:19:21.592819, duration: 3, exit-code: 0
git clone --recursive https://github.com/Lab41/squiggle.git .
Cloning into '.'...

[rtd-command-info] start-time: 2018-07-16T23:19:21.683231, end-time: 2018-07-16T23:19:21.709477, duration: 0, exit-code: 0
git checkout --force origin/master
Note: checking out 'origin/master'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b <new-branch-name>

HEAD is now at 68b4ea3... Ok I'm giving up

[rtd-command-info] start-time: 2018-07-16T23:19:21.790443, end-time: 2018-07-16T23:19:21.801738, duration: 0, exit-code: 0
git clean -d -f -f


[rtd-command-info] start-time: 2018-07-16T23:19:21.922702, end-time: 2018-07-16T23:19:21.931726, duration: 0, exit-code: 0
git branch -r
origin/HEAD -> origin/master
  origin/master

这里是项目的build history以及它的repo。