Fix block_keyword method returning keywords used as arguments of me…

…thod call (#505)

* Fix `block_keyword` method returning keywords used as arguments of methods

* Fix linter errors

* Replace block keyword regex by custom regex to correctly handle newlines

Co-authored-by: Maxime Lapointe <maxhlap@gmail.com>

---------

Co-authored-by: Maxime Lapointe <maxhlap@gmail.com>

lib/haml_lint/ruby_extraction/chunk_extractor.rb

@@ -17,6 +17,10 @@ class ChunkExtractor
                              ::Haml::Parser.new('', {})
                            end
 
+    # HAML strips newlines when handling multi-line statements (using pipes or trailing comma)
+    # We don't. So the regex must be fixed to correctly detect the start of the string.
+    BLOCK_KEYWORD_REGEX = Regexp.new(Haml::Parser::BLOCK_KEYWORD_REGEX.source.sub('^', '\A'))
+
     def initialize(document, script_output_prefix:)
       @document = document
       @script_output_prefix = script_output_prefix
@@ -692,7 +696,7 @@ def self.block_keyword(code)
         return keyword
       end
 
-      return unless keyword = code.scan(Haml::Parser::BLOCK_KEYWORD_REGEX)[0]
+      return unless keyword = code.scan(BLOCK_KEYWORD_REGEX)[0]
       keyword[0] || keyword[1]
     end
   end

spec/haml_lint/ruby_extraction/chunk_extractor_spec.rb

@@ -213,4 +213,73 @@ def do_test
       end
     end
   end
+
+  describe '.block_keyword' do
+    it 'should work for empty strings' do
+      expect(described_class.block_keyword('')).to eq(nil)
+      expect(described_class.block_keyword('             ')).to eq(nil)
+    end
+
+    it 'should extract keywords from simple input' do
+      # Cases where we can use `<keyword> value`
+      %w[if unless case].each do |keyword|
+        input = <<~HAML
+          - #{keyword} foobar
+            = foo
+        HAML
+
+        expect(described_class.block_keyword(input)).to eq(keyword)
+      end
+
+      # Case for the `begin` keyword
+      begin_input = <<~HAML
+        - begin
+      HAML
+
+      expect(described_class.block_keyword(begin_input)).to eq('begin')
+
+      # Case for the `for` keyword
+      for_input = <<~HAML
+        for user in User.all do
+      HAML
+
+      expect(described_class.block_keyword(for_input)).to eq('for')
+
+      # Cases where we can use `<keyword> value do`
+      %w[until while].each do |keyword|
+        input = <<~HAML
+          #{keyword} foobar do
+        HAML
+
+        expect(described_class.block_keyword(input)).to eq(keyword)
+      end
+    end
+
+    it 'should not raise exception when keyword is used as keyword argument' do
+      # Everything on single line, should work
+      input_single_line = '= helper foo: true, bar: true, if: false'
+      expect(described_class.block_keyword(input_single_line)).to eq(nil)
+
+      # Keyword as symbol not first on new line should work
+      input_multiline1 = <<~HAML
+        = helper foo: true,
+                 bar: true, if: false
+      HAML
+      expect(described_class.block_keyword(input_multiline1)).to eq(nil)
+
+      # Keyword as symbol first on new line should also work
+      input_multiline2 = <<~HAML
+        = helper foo: true, bar: true,
+                 if: false
+      HAML
+      expect(described_class.block_keyword(input_multiline2)).to eq(nil)
+
+      # Testing with another keyword
+      input_multiline3 = <<~HAML
+        = helper foo: true, bar: true,
+                 for: User.first
+      HAML
+      expect(described_class.block_keyword(input_multiline3)).to eq(nil)
+    end
+  end
 end