From 4df5e9c991a79cbd7823f5e98da07e599da3557d Mon Sep 17 00:00:00 2001
From: Renato Alves <alves.rjc@gmail.com>
Date: Sat, 15 May 2021 19:06:06 +0000
Subject: [PATCH] Use github-pages gem only when building via GitHub Actions

Allows inclusion of gems that will be relevant in
other CIs such as GitLab.

See pull request #521 for additional context
---
 Gemfile | 46 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/Gemfile b/Gemfile
index 8d69492b..bd6f1d11 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,8 +7,50 @@ git_source(:github) { |repo_name| "/~https://github.com/#{repo_name}" }
 # Synchronize with https://pages.github.com/versions
 ruby '>=2.7.1'
 
-gem 'github-pages', group: :jekyll_plugins
+group :jekyll_plugins do
+  if ENV["GITHUB_ACTIONS"]
+    # When building GitHub Pages via GitHub Actions
+    gem 'github-pages'
+  else
+    # Or elsewhere and if additional gems are necessary.
+    # Note that the 'github-pages' plugin disables any
+    # non-whitelisted plugin.
+    # See PR #521 for additional context
+
+    # Dependency list from 'github-pages'
+    # See: /~https://github.com/github/pages-gem/blob/75fd58be0f294a6bf55a1990643838d5984a1f62/lib/github-pages/dependencies.rb#L8
+    gem 'jekyll', '>= 3.9.0'
+    gem 'jekyll-sass-converter', '>= 1.5.2'
+    # Converters
+    gem 'kramdown', '>= 2.3.1'
+    gem 'kramdown-parser-gfm', '>= 1.1.0'
+    gem 'jekyll-commonmark-ghpages', '>= 0.1.6'
+    # Misc
+    gem 'liquid', '>= 4.0.3'
+    gem 'rouge', '>= 3.26.0'
+    # gem 'github-pages-health-check', '>= 1.17.1'  # Not necessary outside GitHub
+    # Plugins
+    gem 'jekyll-redirect-from', '>= 0.16.0'
+    gem 'jekyll-sitemap', '>= 1.4.0'
+    gem 'jekyll-feed', '>= 0.15.1'
+    gem 'jekyll-gist', '>= 1.5.0'
+    gem 'jekyll-paginate', '>= 1.1.0'
+    gem 'jekyll-coffeescript', '>= 1.1.1'
+    gem 'jekyll-seo-tag', '>= 2.7.1'
+    # gem 'jekyll-github-metadata', '>= 2.13.0'  # Not necessary outside GitHub
+    gem 'jekyll-avatar', '>= 0.7.0'
+    gem 'jekyll-remote-theme', '>= 0.4.3'
+    # Plugins to match GitHub.com Markdown
+    gem 'jemoji', '>= 0.12.0'
+    gem 'jekyll-mentions', '>= 1.6.0'
+    gem 'jekyll-relative-links', '>= 0.6.1'
+    gem 'jekyll-optional-front-matter', '>= 0.3.2'
+    gem 'jekyll-readme-index', '>= 0.3.0'
+    gem 'jekyll-default-layout', '>= 0.1.4'
+    gem 'jekyll-titles-from-headings', '>= 0.5.3'
+  end
+end
 
 if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('3.0.0')
     gem 'webrick', '>= 1.6.1'
-end
\ No newline at end of file
+end