Remove dependencies on Linguist

This saves about 128 MB of baseline RAM usage per Unicorn and
Sidekiq process (!).

Linguist wasn't detecting languages anymore from CE/EE since
9ae8b57467ac8b38f1fa9020a466d94a93cbb9dd. However, Linguist::BlobHelper
was still being depended on by BlobLike and others.

This removes the Linguist gem, given it isn't required anymore.
EscapeUtils were pulled in as dependency, but given Banzai depends on
it, it is now added explicitly.

Previously, Linguist was used to detect the best ACE mode. Instead,
we rely on ACE to guess the best mode based on the file extension.

1 files changed, 22 insertions, 0 deletions

diff --git a/spec/lib/gitlab/language_data_spec.rb b/spec/lib/gitlab/language_data_spec.rb
new file mode 100644
index 00000000000..b08150855fe
--- /dev/null
+++ b/spec/lib/gitlab/language_data_spec.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::LanguageData do
+  describe '#extensions' do
+    before do
+      described_class.clear_extensions!
+    end
+
+    it 'loads the extensions once' do
+      expect(YAML).to receive(:load_file).once.and_call_original
+
+      2.times do
+        expect(described_class.extensions).to be_a(Set)
+        expect(described_class.extensions.count).to be > 0
+        # Sanity check for known extensions
+        expect(described_class.extensions).to include(*%w(.rb .yml .json))
+      end
+    end
+  end
+end