v1 site does not deploy due to CircleCI

[slorber]

🐛 Bug Report

Opening this bug report mostly to document this issue.

When we merge on master some new code, CircleCI is supposed to run, and deploy the v1 website on GH pages if there is any git diff change.

      - run:
          name: Deploy v1 Website
          # Skip the deploy if we don't have the right org (facebook), or if this is just a pull request
          command: |
            if ! git diff-tree --no-commit-id --name-only -r HEAD | grep -E "(^docs\/.*)|(docusaurus-1\.x\/.*)|(website-1\.x\/.*)"; then
              echo "Skipping deploy. No relevant v1 website files have changed"
            elif [[ $CIRCLE_PROJECT_USERNAME == "facebook" && -z $CI_PULL_REQUEST && -z $CIRCLE_PR_USERNAME ]]; then
              echo "Deploying website v1..."
            else
              echo "Skipping deploy."
            fi

The problem is that some of our users are using a Github pull bot that opens a PR to sync their fork whenever we push to master.

kadirselcuk#41

We end up with $CI_PULL_REQUEST to never be empty for CircleCI (looks like a bug to me), and the v1 site deploy is constantly skipped.

For example https://app.circleci.com/pipelines/github/facebook/docusaurus/3917/workflows/cd176276-dd7b-42da-9e88-607f6d1a450e/jobs/22218

I will simplify the workflow to fix this temporarily, but soon the v1 site deployment will be on netlify (note: v1.docusaurus.io is already using netlify and deploys fine)

[slorber]

Hopefully, $CIRCLE_PR_USERNAME is not set in this case, as it's only set in forks.

While this one (new name for deprecated CI_PULL_REQUEST) seems to be able to be set in upstream:

[slorber]

fixed by #4395