Add latest changes from gitlab-org/gitlab@master

1 files changed, 232 insertions, 0 deletions

diff --git a/lib/gitlab/danger/commit_linter.rb b/lib/gitlab/danger/commit_linter.rb
new file mode 100644
index 00000000000..c0748a4b8e6
--- /dev/null
+++ b/lib/gitlab/danger/commit_linter.rb
@@ -0,0 +1,232 @@
+# frozen_string_literal: true
+
+emoji_checker_path = File.expand_path('emoji_checker', __dir__)
+defined?(Rails) ? require_dependency(emoji_checker_path) : require_relative(emoji_checker_path)
+
+module Gitlab
+  module Danger
+    class CommitLinter
+      MIN_SUBJECT_WORDS_COUNT = 3
+      MAX_LINE_LENGTH = 72
+      WARN_SUBJECT_LENGTH = 50
+      URL_LIMIT_SUBJECT = "https://chris.beams.io/posts/git-commit/#limit-50"
+      MAX_CHANGED_FILES_IN_COMMIT = 3
+      MAX_CHANGED_LINES_IN_COMMIT = 30
+      SHORT_REFERENCE_REGEX = %r{([\w\-\/]+)?(#|!|&|%)\d+\b}.freeze
+      DEFAULT_SUBJECT_DESCRIPTION = 'commit subject'
+      PROBLEMS = {
+        subject_too_short: "The %s must contain at least #{MIN_SUBJECT_WORDS_COUNT} words",
+        subject_too_long: "The %s may not be longer than #{MAX_LINE_LENGTH} characters",
+        subject_above_warning: "The %s length is acceptable, but please try to [reduce it to #{WARN_SUBJECT_LENGTH} characters](#{URL_LIMIT_SUBJECT}).",
+        subject_starts_with_lowercase: "The %s must start with a capital letter",
+        subject_ends_with_a_period: "The %s must not end with a period",
+        separator_missing: "The commit subject and body must be separated by a blank line",
+        details_too_many_changes: "Commits that change #{MAX_CHANGED_LINES_IN_COMMIT} or more lines across " \
+          "at least #{MAX_CHANGED_FILES_IN_COMMIT} files must describe these changes in the commit body",
+        details_line_too_long: "The commit body should not contain more than #{MAX_LINE_LENGTH} characters per line",
+        message_contains_text_emoji: "Avoid the use of Markdown Emoji such as `:+1:`. These add limited value " \
+          "to the commit message, and are displayed as plain text outside of GitLab",
+        message_contains_unicode_emoji: "Avoid the use of Unicode Emoji. These add no value to the commit " \
+          "message, and may not be displayed properly everywhere",
+        message_contains_short_reference: "Use full URLs instead of short references (`gitlab-org/gitlab#123` or " \
+          "`!123`), as short references are displayed as plain text outside of GitLab"
+      }.freeze
+
+      attr_reader :commit, :problems
+
+      def initialize(commit)
+        @commit = commit
+        @problems = {}
+        @linted = false
+      end
+
+      def fixup?
+        commit.message.start_with?('fixup!', 'squash!')
+      end
+
+      def suggestion?
+        commit.message.start_with?('Apply suggestion to')
+      end
+
+      def merge?
+        commit.message.start_with?('Merge branch')
+      end
+
+      def revert?
+        commit.message.start_with?('Revert "')
+      end
+
+      def multi_line?
+        !details.nil? && !details.empty?
+      end
+
+      def failed?
+        problems.any?
+      end
+
+      def add_problem(problem_key, *args)
+        @problems[problem_key] = sprintf(PROBLEMS[problem_key], *args)
+      end
+
+      def lint(subject_description = "commit subject")
+        return self if @linted
+
+        @linted = true
+        lint_subject(subject_description)
+        lint_separator
+        lint_details
+        lint_message
+
+        self
+      end
+
+      def lint_subject(subject_description)
+        if subject_too_short?
+          add_problem(:subject_too_short, subject_description)
+        end
+
+        if subject_too_long?
+          add_problem(:subject_too_long, subject_description)
+        elsif subject_above_warning?
+          add_problem(:subject_above_warning, subject_description)
+        end
+
+        if subject_starts_with_lowercase?
+          add_problem(:subject_starts_with_lowercase, subject_description)
+        end
+
+        if subject_ends_with_a_period?
+          add_problem(:subject_ends_with_a_period, subject_description)
+        end
+
+        self
+      end
+
+      private
+
+      def lint_separator
+        return self unless separator && !separator.empty?
+
+        add_problem(:separator_missing)
+
+        self
+      end
+
+      def lint_details
+        if !multi_line? && many_changes?
+          add_problem(:details_too_many_changes)
+        end
+
+        details&.each_line do |line|
+          line = line.strip
+
+          next unless line_too_long?(line)
+
+          url_size = line.scan(%r((https?://\S+))).sum { |(url)| url.length } # rubocop:disable CodeReuse/ActiveRecord
+
+          # If the line includes a URL, we'll allow it to exceed MAX_LINE_LENGTH characters, but
+          # only if the line _without_ the URL does not exceed this limit.
+          next unless line_too_long?(line.length - url_size)
+
+          add_problem(:details_line_too_long)
+          break
+        end
+
+        self
+      end
+
+      def lint_message
+        if message_contains_text_emoji?
+          add_problem(:message_contains_text_emoji)
+        end
+
+        if message_contains_unicode_emoji?
+          add_problem(:message_contains_unicode_emoji)
+        end
+
+        if message_contains_short_reference?
+          add_problem(:message_contains_short_reference)
+        end
+
+        self
+      end
+
+      def files_changed
+        commit.diff_parent.stats[:total][:files]
+      end
+
+      def lines_changed
+        commit.diff_parent.stats[:total][:lines]
+      end
+
+      def many_changes?
+        files_changed > MAX_CHANGED_FILES_IN_COMMIT && lines_changed > MAX_CHANGED_LINES_IN_COMMIT
+      end
+
+      def subject
+        message_parts[0]
+      end
+
+      def separator
+        message_parts[1]
+      end
+
+      def details
+        message_parts[2]
+      end
+
+      def line_too_long?(line)
+        case line
+        when String
+          line.length > MAX_LINE_LENGTH
+        when Integer
+          line > MAX_LINE_LENGTH
+        else
+          raise ArgumentError, "The line argument (#{line}) should be a String or an Integer! #{line.class} given."
+        end
+      end
+
+      def subject_too_short?
+        subject.split(' ').length < MIN_SUBJECT_WORDS_COUNT
+      end
+
+      def subject_too_long?
+        line_too_long?(subject)
+      end
+
+      def subject_above_warning?
+        subject.length > WARN_SUBJECT_LENGTH
+      end
+
+      def subject_starts_with_lowercase?
+        first_char = subject[0]
+
+        first_char.downcase == first_char
+      end
+
+      def subject_ends_with_a_period?
+        subject.end_with?('.')
+      end
+
+      def message_contains_text_emoji?
+        emoji_checker.includes_text_emoji?(commit.message)
+      end
+
+      def message_contains_unicode_emoji?
+        emoji_checker.includes_unicode_emoji?(commit.message)
+      end
+
+      def message_contains_short_reference?
+        commit.message.match?(SHORT_REFERENCE_REGEX)
+      end
+
+      def emoji_checker
+        @emoji_checker ||= Gitlab::Danger::EmojiChecker.new
+      end
+
+      def message_parts
+        @message_parts ||= commit.message.split("\n", 3)
+      end
+    end
+  end
+end