build: set up PullApprove for reviews

[crisbeto]

Replaces Github's code review assignments with PullApprove which is a bit more configurable and which can help reduce noise for the team.

[crisbeto]

I'm not a fan of listing out all these top-level files, but I'm not sure if there's a way to:

1. Have the components-team own all files by default.
2. Have some infra-specific files be owned by the components-infra team.

[josephperrott]

You could have a rule for components-team that doesn't have any file matching conditions, but has a condition that no other rule above it matches.

The rules are processed in order in the yaml, so if you have a components-infra group that matches it, you can then later just have the other rule match "everything that isn't already matched"

I think...

[josephperrott]

/pullapprove-test

version: 3

# Add users here if they're temporarily unavailable.
#availability:
#  users_unavailable: []

# Meta field that goes unused by PullApprove to allow for defining aliases to be
# used throughout the config.
meta:
  no-groups-above-this-active: &no-groups-above-this-active len(groups.active.exclude("components-team")) == 0

  defaults: &defaults
    reviews:
      # Authors provide their approval implicitly, this approval allows for a reviewer
      # from a group not to need a review specifically for an area of the repository
      # they own.  This is coupled with the `required-minimum-review` group which requires
      # that all PRs are reviewed by at least one team member who is not the author of
      # the PR.
      author_value: 1

# turn on 'draft' support
# https://docs.pullapprove.com/config/github-api-version/
# https://developer.github.com/v3/previews/#draft-pull-requests
github_api_version: 'shadow-cat-preview'

# https://docs.pullapprove.com/config/overrides/
# Note that overrides are processed in order.
overrides:
  # For PRs which are still being worked on, either still in draft mode or indicated through WIP in
  # title or label, PullApprove stays in a pending state until its ready for review.
  - if: "draft or 'WIP' in title or 'PR state: WIP' in labels"
    status: pending
    explanation: 'Waiting to send reviews as PR is WIP'
  # Disable PullApprove on specific PRs by adding the `PullApprove: disable` label
  - if: "'PullApprove: disable' in labels"
    status: success
    explanation: "PullApprove skipped because of 'PullApprove: disable' label"
  # If no file matching based groups are active, report this pull request as failing. Most likely,
  # the PR author would need to update the PullApprove config, or create new group.
  - if: len(groups.active) == 0
    status: failure
    explanation: 'At least one group must match this PR. Please update an existing review group, or create a new group.'

groups:
  components-infra:
    <<: *defaults
    conditions:
      - author not in ["angular-robot"]
      - >
        contains_any_globs(files, [
          '.bazel_fix_commands.json',
          '.bazelignore',
          '.bazelrc',
          '.bazelversion',
          '.firebaserc',
          '.git-blame-ignore-revs',
          '.gitignore',
          '.npmrc',
          '.nvmrc',
          '.pullapprove.yml',
          'firebase.json',
          'LICENSE',
          'renovate.json',
          'tsconfig.json',
          '.github/**/{*,.*}',
          '.husky/**/{*,.*}',
          '.ng-dev/**/{*,.*}',
          '.vscode/**/{*,.*}',
          'scripts/**/{*,.*}',
          'test/**/{*,.*}',
          'tools/**/{*,.*}',
        ])
    reviews:
      request: 1 # Request at least one review
      required: 1 # Require that all PRs have approval from at least one of the users in the group
      author_value: 0 # The author of the PR cannot provide an approval for themself
    reviewers:
      users:
        - crisbeto
        - devversion
        - andrewseguin
        - josephperrott

  components-team:
    <<: *defaults
    conditions:
      - *no-groups-above-this-active
      - >
        contains_any_globs(files, [
          '**/{.*,*}/**',
          '**/{.*,*}',
        ])
    reviews:
      request: 2 # Request at least two reviews
      required: 1 # Require that all PRs have approval from at least one of the users in the group
      author_value: 0 # The author of the PR cannot provide an approval for themself
    reviewers:
      users:
        - adolgachev
        - crisbeto
        - mmalerba
        - andrewseguin
        - wagnermaciel
        - tjshiu
        - ok7sai
        - ~devversion
        - ~josephperrott

[pullapprove]

View the results of /pullapprove-test