From 01de40faaaa990394063925f51bec8472753be87 Mon Sep 17 00:00:00 2001
From: Colin Seymour <colin@github.com>
Date: Mon, 13 Feb 2017 18:22:54 +0000
Subject: [PATCH] Return early in Classifier.classify if no languages supplied
 (#3471)

* Return early if no languages supplied

There's no need to tokenise the data when attempting to classify without a limited language scope as no action will be performed when it comes to scoring anyway.

* Add test for empty languages array
---
 lib/linguist/classifier.rb | 2 +-
 test/test_classifier.rb    | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/linguist/classifier.rb b/lib/linguist/classifier.rb
index 89a0df2f..4d549cc9 100644
--- a/lib/linguist/classifier.rb
+++ b/lib/linguist/classifier.rb
@@ -95,7 +95,7 @@ module Linguist
     # Returns sorted Array of result pairs. Each pair contains the
     # String language name and a Float score.
     def classify(tokens, languages)
-      return [] if tokens.nil?
+      return [] if tokens.nil? || languages.empty?
       tokens = Tokenizer.tokenize(tokens) if tokens.is_a?(String)
       scores = {}
 
diff --git a/test/test_classifier.rb b/test/test_classifier.rb
index 2ae2f45e..818bee29 100644
--- a/test/test_classifier.rb
+++ b/test/test_classifier.rb
@@ -53,4 +53,8 @@ class TestClassifier < Minitest::Test
       assert_equal language.name, results.first[0], "#{sample[:path]}\n#{results.inspect}"
     end
   end
+
+  def test_classify_empty_languages
+    assert_equal [], Classifier.classify(Samples.cache, fixture("Ruby/foo.rb"), [])
+  end
 end