Fix SpaceAfterComma to not infinite loop on multline map literals

Fixes #642

Author: sds

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 * Add `placeholder`, `-moz-*`, `-ms-*`, and `-webkit-*` to `PseudoElement`
   linter
+* Fix `SpaceAfterComma` to not infinite loop on map literals as arguments
+  spanning multiple lines
 
 ## 0.43.0
 

lib/scss_lint/linter.rb

@@ -181,6 +181,8 @@ def character_at(source_position, offset = 0)
       actual_line   = source_position.line - 1
       actual_offset = source_position.offset + offset - 1
 
+      return nil if actual_offset < 0
+
       engine.lines.size > actual_line && engine.lines[actual_line][actual_offset]
     end
 

lib/scss_lint/linter/space_after_comma.rb

@@ -78,19 +78,18 @@ def check_commas_after_args(args, arg_type)
         # Sometimes the line we're looking at doesn't even contain a comma!
         next unless engine.lines[arg.line - 1].include?(',')
 
-        offset = find_comma_offset(arg)
+        comma_position = find_comma_position(arg)
 
         # Check for space or newline after comma (we allow arguments to be split
         # up over multiple lines).
         spaces = 0
-        while (char = character_at(arg.source_range.end_pos, offset + 1)) == ' '
+        while (char = character_at(comma_position, spaces + 1)) == ' '
           spaces += 1
-          offset += 1
         end
         next if char == "\n" || # Ignore trailing spaces
                 valid_spaces_after_comma?(spaces)
 
-        add_lint arg, "Commas in #{arg_type} should be followed by a single space"
+        add_lint comma_position, "Commas in #{arg_type} should be followed by a single space"
       end
     end
 
@@ -100,20 +99,26 @@ def check_commas_after_args(args, arg_type)
     # source range. Thus we need to start at the indicated range, and check
     # left and right of that range, gradually moving further outward until
     # we find the comma.
-    def find_comma_offset(arg)
+    def find_comma_position(arg) # rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity
       offset = 0
+      pos = arg.source_range.end_pos
 
-      if character_at(arg.source_range.end_pos, offset) != ','
+      if character_at(pos, offset) != ','
         loop do
           offset += 1
-          break if character_at(arg.source_range.end_pos, offset) == ','
+          break if (right_char = character_at(pos, offset)) == ','
           offset = -offset
-          break if character_at(arg.source_range.end_pos, offset) == ','
+          break if (left_char = character_at(pos, offset)) == ','
           offset = -offset
+
+          next unless right_char.nil? && left_char.nil?
+          offset = 0
+          pos = Sass::Source::Position.new(pos.line + 1, 1)
+          break if character_at(pos, offset) == ','
         end
       end
 
-      offset
+      Sass::Source::Position.new(pos.line, pos.offset + offset)
     end
   end
 end

spec/scss_lint/linter/space_after_comma_spec.rb

@@ -334,6 +334,18 @@
         it { should_not report_lint }
       end
     end
+
+    context 'when map literal spans multiple lines' do
+      let(:scss) { <<-SCSS }
+      @include mixin('arg1', (
+          key1: 'arg2-key1-value',
+          key2: 'arg2-key2-value'
+        ),$arg3: 'arg3-value', $arg4: 'arg4-value'
+      );
+      SCSS
+
+      it { should report_lint line: 4 }
+    end
   end
 
   context 'when more than one space is preferred' do