It appears that some legacy diff notes on GitLab.com have invalid line codes,
which means truncated_diff_lines won't work. This is just a band-aid solution,
as neither the diff nor the discussion will display correctly for these notes,
but they won't cause a 500 error.

System hooks for Merge Requests

See merge request gitlab-org/gitlab-ce!14387

with .public_send we can't make sure that the scope on the model
actually exists.

CE: Override module to specify that we're overriding

See merge request gitlab-org/gitlab-ce!16131

* upstream/master: (621 commits)
  Add a note about GitLab QA page objects validator to docs
  Refactor dispatcher projects blame and blob path
  Update export message to mention we can download the file from the UI
  Fix Ctrl+Enter keyboard shortcut saving comment/note edit
  fix case where tooltip messes up :last-child selector
  Add reason to keep postgresql 9.2 for CI
  Remove warning noise in ProjectImportOptions
  Add changelog entry
  Add RedirectRoute factory
  Update Ingress extra cost note to be more generic
  Fix Rubocop offense
  Refactor dispatcher project branches path
  Revert "Revert "Fix Route validation for unchanged path""
  Document that we need rsync for backing up
  Docs: move article "Laravel and Envoy w/ CI/CD"
  Recommend against the use of EFS
  Adds Rubocop rule for line break around conditionals
  Update CHANGELOG.md for 10.1.6
  Filter out build traces from logged parameters
  Refactored project:n* imports in dispatcher.js
  ...

with StrongMemoize