add counter support and title counter

Author: khiga8

README.md

@@ -35,6 +35,8 @@ linters:
     enabled: true
   GitHub::Accessibility::NoRedundantImageAlt:
     enabled: true
+  GitHub::Accessibility::NoTitleAttributeCounter:
+    enabled: true
 ```
 
 ## Rules
@@ -45,6 +47,7 @@ linters:
 - [GitHub::Accessibility::NoAriaLabelMisuse](./docs/rules/accessibility/no-aria-label-misuse.md)
 - [GitHub::Accessibility::NoPositiveTabIndex](./docs/rules/accessibility/no-positive-tab-index.md)
 - [GitHub::Accessibility::NoRedundantImageAlt](./docs/rules/accessibility/no-redundant-image-alt.md)
+- [GitHub::Accessibility::NoTitleAttributeCounter](./docs/rules/accessibility/no-title-attribute-counter.md)
 
 ## Testing
 

docs/rules/accessibility/no-title-attribute-counter.md

@@ -0,0 +1,39 @@
+# No title attribute counter
+
+## Rule Details
+
+The `title` attribute is strongly discouraged. The only exception is on an `<iframe>` element. It is hardly useful and cannot be accessed by multiple groups of users including keyboard-only users and mobile users.
+
+The `title` attribute is commonly seen set on links, matching the link text. This is redundant and unnecessary so it can be simply be removed.
+
+If you are considering `title` attribute to provide supplementary description, consider whether the text in question can be persisted in the design. Alternatively, if it's important to display supplementary text that is hidden by default, consider using an **accessible** tooltip implementation that uses the `aria-labelledby` or `aria-describedby` semantics. Even so, proceed with caution: tooltips should only be used on interactive elements like links or buttons.
+
+### Should I use `title` attribute to provide accessible name for `<svg>`?
+
+Use a `<title>` element instead of the `title` attribute, or an `aria-label`.
+
+### Resources
+
+- [TPGI: Using the HTML title attribute ](https://www.tpgi.com/using-the-html-title-attribute/)
+- [The Trials and Tribulations of the Title Attribute](https://www.24a11y.com/2017/the-trials-and-tribulations-of-the-title-attribute/)
+
+### 👎 Examples of **incorrect** code for this rule:
+
+```erb
+<a title="A home for all developers" href="github.com">GitHub</a>
+```
+
+```
+<a href="/" title="github.com">GitHub</a>
+```
+
+### 👍 Examples of **correct** code for this rule:
+
+```erb
+<a href="github.com" aria-describedby="description">GitHub</a>
+<p id="description" class="tooltip js-tooltip">A home for all developers</p>
+```
+
+```
+<a href="github.com">GitHub</a>
+```

lib/erblint-github/linters/custom_helpers.rb

@@ -24,6 +24,41 @@ def rule_disabled?(processed_source)
         end
       end
 
+      def counter_correct?(processed_source)
+        comment_node = nil
+        expected_count = 0
+        rule_name = self.class.name.match(/:?:?(\w+)\Z/)[1]
+        offenses_count = @offenses.length
+
+        processed_source.parser.ast.descendants(:erb).each do |node|
+          indicator_node, _, code_node, _ = *node
+          indicator = indicator_node&.loc&.source
+          comment = code_node&.loc&.source&.strip
+
+          if indicator == "#" && comment.start_with?("erblint:count") && comment.match(rule_name)
+            comment_node = node
+            expected_count = comment.match(/\s(\d+)\s?$/)[1].to_i
+          end
+        end
+
+        if offenses_count == 0
+          # have to adjust to get `\n` so we delete the whole line
+          add_offense(processed_source.to_source_range(comment_node.loc.adjust(end_pos: 1)), "Unused erblint:count comment for #{rule_name}", "") if comment_node
+          return
+        end
+
+        first_offense = @offenses[0]
+
+        if comment_node.nil?
+          add_offense(processed_source.to_source_range(first_offense.source_range), "#{rule_name}: If you must, add <%# erblint:counter #{rule_name} #{offenses_count} %> to bypass this check.", "<%# erblint:counter #{rule_name} #{offenses_count} %>")
+        else
+          clear_offenses
+          if expected_count != offenses_count
+            add_offense(processed_source.to_source_range(comment_node.loc), "Incorrect erblint:counter number for #{rule_name}. Expected: #{expected_count}, actual: #{offenses_count}.", "<%#  erblint:counter #{rule_name} #{offenses_count} %>")
+          end
+        end
+      end
+
       def generate_offense(klass, processed_source, tag, message = nil, replacement = nil)
         message ||= klass::MESSAGE
         message += "\nLearn more at https://github.com/github/erblint-github#rules.\n"

lib/erblint-github/linters/github/accessibility/no_title_attribute_counter.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require_relative "../../custom_helpers"
+
+module ERBLint
+  module Linters
+    module GitHub
+      module Accessibility
+        class NoTitleAttributeCounter < Linter
+          include ERBLint::Linters::CustomHelpers
+          include LinterRegistry
+
+          MESSAGE = "The title attribute is inaccesible to several groups of users. Please avoid setting unless for an `<iframe>`."
+
+          def run(processed_source)
+            tags(processed_source).each do |tag|
+              next if tag.name != "iframe"
+              next if tag.closing?
+
+              title = possible_attribute_values(tag, "title")
+
+              generate_offense(self.class, processed_source, tag) if title.present?
+            end
+
+            counter_correct?(processed_source)
+          end
+
+          private
+
+          def correct_counter(corrector, processed_source, offense)
+            if processed_source.file_content.include?("erblint:counter DeprecatedInPrimerCounter")
+              corrector.replace(offense.source_range, offense.context)
+            else
+              corrector.insert_before(processed_source.source_buffer.source_range, "#{offense.context}\n")
+            end
+          end
+
+          def autocorrect(processed_source, offense)
+            return unless offense.context
+    
+            lambda do |corrector|
+              if offense.context.include?("erblint:counter DeprecatedInPrimerCounter")
+                correct_counter(corrector, processed_source, offense)
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end