Improve Emoji detection in commit messages

This changes our Danger integration so that it is smarter about
detecting GitLab emoji in commit messages. This is done using a two step

1. We use the old regular expression to determine if a commit message
   _might_ include an emoji.

2. If this regular expression matches, we then check for all existing
   emoji names in the commit message. This might be a wee bit expensive,
   but because we couple it with the previous step it should be rarely

This ensures we don't trigger an error when a commit message includes
text such as `:foo:bar:`, which is not a valid Emoji.

parent a2a00a5e
# frozen_string_literal: true
require 'json'
# rubocop: disable Style/SignalException
# rubocop: disable Metrics/CyclomaticComplexity
# rubocop: disable Metrics/PerceivedComplexity
......@@ -8,6 +10,30 @@
# because its output is not
# very helpful, and it doesn't offer the means of ignoring merge commits.
class EmojiChecker
DIGESTS = File.expand_path('../../fixtures/emojis/digests.json', __dir__)
ALIASES = File.expand_path('../../fixtures/emojis/aliases.json', __dir__)
# A regex that indicates a piece of text _might_ include an Emoji. The regex
# alone is not enough, as we'd match `:foo:bar:baz`. Instead, we use this
# regex to save us from having to check for all possible emoji names when we
# know one definitely is not included.
LIKELY_EMOJI = /:[\+a-z0-9_\-]+:/
def initialize
names = JSON.parse( +
@emoji = { |name| ":#{name}:" }
def includes_emoji?(text)
return false unless text.match?(LIKELY_EMOJI)
@emoji.any? { |emoji| text.include?(emoji) }
def fail_commit(commit, message)
fail("#{commit.sha}: #{message}")
......@@ -33,6 +59,7 @@ end
def lint_commits(commits)
failures = false
emoji_checker =
unicode_emoji_regex = %r((
[\u{1F300}-\u{1F5FF}] |
......@@ -117,7 +144,7 @@ def lint_commits(commits)
failures = true
if commit.message.match?(/:[\+a-z0-9_\-]+:/)
if emoji_checker.includes_emoji?(commit.message)
'Avoid the use of Markdown Emoji such as `:+1:`. ' \
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