Check !default, !global, and !optional flags in BangFormat

This linter was not visiting variable declarations or `@extend`
directives, so it was not checking for `!default`, `!global`, and
`!optional`.

CHANGELOG.md

@@ -3,6 +3,8 @@
 ## master (unreleased)
 
 * Fix `TrailingSemicolon` for variables with `!default` and `!global`.
+* Check `!default` and `!global` variable declarations and `!optional` `@extend`
+  directives in `BangFormat`
 
 ## 0.42.0
 

lib/scss_lint/linter/README.md

@@ -62,7 +62,7 @@ Below is a list of linters supported by `scss-lint`, ordered alphabetically.
 
 ## BangFormat
 
-Reports when you use improper spacing around `!` (the "bang") in `!important` and `!default` declarations.
+Reports when you use improper spacing around `!` (the "bang") in `!default`, `!global`, `!important`, and `!optional` flags.
 
 You can prefer a single space or no space both before and after the `!`.
 

lib/scss_lint/linter/bang_format.rb

@@ -5,9 +5,28 @@ class Linter::BangFormat < Linter
 
     STOPPING_CHARACTERS = ['!', "'", '"', nil]
 
+    def visit_extend(node)
+      check_bang(node)
+    end
+
     def visit_prop(node)
-      return unless source_from_range(node.source_range).include?('!')
-      return unless check_spacing(node)
+      check_bang(node)
+    end
+
+    def visit_variable(node)
+      check_bang(node)
+    end
+
+  private
+
+    def check_bang(node)
+      range = if node.respond_to?(:value_source_range)
+                node.value_source_range
+              else
+                node.source_range
+              end
+      return unless source_from_range(range).include?('!')
+      return unless check_spacing(range)
 
       before_qualifier = config['space_before_bang'] ? '' : 'not '
       after_qualifier = config['space_after_bang'] ? '' : 'not '
@@ -16,8 +35,6 @@ def visit_prop(node)
                      "and should #{after_qualifier}be followed by a space")
     end
 
-  private
-
     # Start from the back and move towards the front so that any !important or
     # !default !'s will be found *before* quotation marks. Then we can
     # stop at quotation marks to protect against linting !'s within strings
@@ -40,8 +57,7 @@ def is_after_wrong?(range, offset)
       (after_actual =~ after_expected).nil?
     end
 
-    def check_spacing(node)
-      range = node.value_source_range
+    def check_spacing(range)
       offset = find_bang_offset(range)
 
       return if character_at(range.end_pos, offset) != '!'

spec/scss_lint/linter/bang_format_spec.rb

@@ -77,6 +77,64 @@
     it { should_not report_lint }
   end
 
+  context 'with a !default variable declaration' do
+    context 'and !default is used correctly' do
+      let(:scss) { <<-SCSS }
+        $foo: bar !default;
+      SCSS
+
+      it { should_not report_lint }
+    end
+
+    context 'and there is no space before' do
+      let(:scss) { <<-SCSS }
+        $foo: bar!default;
+      SCSS
+
+      it { should report_lint line: 1 }
+    end
+  end
+
+  context 'with a !global variable declaration' do
+    context 'and !global is used correctly' do
+      let(:scss) { <<-SCSS }
+        $foo: bar !global;
+      SCSS
+
+      it { should_not report_lint }
+    end
+
+    context 'and there is no space before' do
+      let(:scss) { <<-SCSS }
+        $foo: bar!global;
+      SCSS
+
+      it { should report_lint line: 1 }
+    end
+  end
+
+  context 'with an !optional @extend directive' do
+    context 'and !optional is used correctly' do
+      let(:scss) { <<-SCSS }
+        .foo {
+          @extend .bar !optional;
+        }
+      SCSS
+
+      it { should_not report_lint }
+    end
+
+    context 'and there is no space before' do
+      let(:scss) { <<-SCSS }
+        .foo {
+          @extend .bar!optional;
+        }
+      SCSS
+
+      it { should report_lint line: 2 }
+    end
+  end
+
   context 'when ! appears within a string' do
     let(:scss) { <<-SCSS }
       p:before { content: "!important"; }