Switching leading_underscore convention to option

Rather than have this be an entire convention, create an option
`allow_leading_underscore` which regardless of convention specified
allows you to prefix names with underscores to denote them as private.

Change-Id: I380cdf84d8e5d263b76b033137a9e4a69025d9ca
Reviewed-on: http://gerrit.causes.com/45099
Tested-by: jenkins <[email protected]>
Reviewed-by: Shane da Silva <[email protected]>

CHANGELOG.md

@@ -21,7 +21,8 @@
 * Fix `DuplicateProperty` to report correct name of duplicated property
 * Add `smacss` sort order option for `PropertySortOrder`
 * Add `recess` sort order option for `PropertySortOrder`
-* Add `leading_underscore` option for `NameFormat`
+* Add `allow_leading_underscore` option to `NameFormat` to allow the leading
+  underscore convention to denote private functions
 
 ## 0.30.0
 

config/default.yml

@@ -75,6 +75,7 @@ linters:
 
   NameFormat:
     enabled: true
+    allow_leading_underscore: true
     convention: hyphenated_lowercase # or 'BEM', or a regex pattern
 
   NestingDepth:

lib/scss_lint/linter/README.md

@@ -565,16 +565,18 @@ The Sass parser automatically treats underscores and hyphens the same, so even
 if you're using a library that declares a function with an underscore, you can
 refer to it using the hyphenated form instead.
 
-If you use underscores to denote private functions within your Sass, you can set
-the `leading_underscore` option which will enforce all lowercase with hyphens
-but allow a single leading underscore like `@function _private-function() {}`.
+Depending on whether you use underscores to denote private functions within your
+code, you can set the `allow_leading_underscore` option (enabled by default)
+which will ignore leading underscores in names if they exist, allowing
+declarations like `@function _private-function() { ... }`.
 
 You can also prefer the [BEM](http://bem.info/method/) convention by setting the
 `convention` option to `BEM`. Any other value will be treated as a regex.
 
-Configuration Option | Description
----------------------|---------------------------------------------------------
-`convention`         | Name of convention to use (`hyphenated_lowercase` (default) or `BEM`), or a regex the name must match
+Configuration Option       | Description
+---------------------------|---------------------------------------------------
+`allow_leading_underscore` | Whether to allow names to start with a single underscore (default `true`)
+`convention`               | Name of convention to use (`hyphenated_lowercase` (default) or `BEM`), or a regex the name must match
 
 ## NestingDepth
 

lib/scss_lint/linter/name_format.rb

@@ -46,12 +46,23 @@ def visit_variable(node)
     ].to_set
 
     def check_name(node, node_type, node_text = node.name)
+      node_text = trim_underscore_prefix(node_text)
       return unless violation = violated_convention(node_text)
 
       add_lint(node, "Name of #{node_type} `#{node_text}` should be " \
                      "written #{violation[:explanation]}")
     end
 
+    # Removes underscore prefix from name if leading underscores are allowed.
+    def trim_underscore_prefix(name)
+      if config['allow_leading_underscore']
+        # Remove if there is a single leading underscore
+        name = name.gsub(/^_(?!_)/, '')
+      end
+
+      name
+    end
+
     def check_placeholder(node)
       extract_string_selectors(node.selector).any? do |selector_str|
         check_name(node, 'placeholder', selector_str.gsub('%', ''))
@@ -63,10 +74,6 @@ def check_placeholder(node)
         explanation: 'in all lowercase letters with hyphens instead of underscores',
         validator: ->(name) { name !~ /[_A-Z]/ },
       },
-      'leading_underscore' => {
-        explanation: 'hyphenated_lowercase with leading underscores permitted',
-        validator: ->(name) { name !~ /[^_][_A-Z]/ },
-      },
       'BEM' => {
         explanation: 'in BEM (Block Element Modifier) format',
         validator: ->(name) { name !~ /[A-Z]|-{3}|_{3}|[^_]_[^_]/ },

spec/scss_lint/linter/name_format_spec.rb

@@ -175,12 +175,12 @@
         }
       CSS
 
-      it { should report_lint }
+      it { should_not report_lint }
     end
   end
 
-  context 'when the leading underscore style is specified' do
-    let(:linter_config) { { 'convention' => 'leading_underscore' } }
+  context 'when leading underscores are not allowed' do
+    let(:linter_config) { { 'allow_leading_underscore' => false } }
 
     it_behaves_like 'hyphenated_lowercase'
 
@@ -190,7 +190,7 @@
         }
       CSS
 
-      it { should_not report_lint }
+      it { should report_lint line: 1 }
     end
   end