Fix being able to retrieve unusable hashtags through the API

app/controllers/api/v1/tags_controller.rb

@@ -29,5 +29,7 @@ class Api::V1::TagsController < Api::BaseController
     return not_found unless Tag::HASHTAG_NAME_RE.match?(params[:id])
 
     @tag = Tag.find_normalized(params[:id]) || Tag.new(name: Tag.normalize(params[:id]), display_name: params[:id])
+
+    not_found unless @tag.usable?
   end
 end

app/controllers/api/v1/timelines/tag_controller.rb

@@ -19,7 +19,7 @@ class Api::V1::Timelines::TagController < Api::V1::Timelines::BaseController
   end
 
   def load_tag
-    @tag = Tag.find_normalized(params[:id])
+    @tag = Tag.usable.find_normalized(params[:id])
   end
 
   def load_statuses

app/lib/search_query_transformer.rb

@@ -13,6 +13,8 @@ class SearchQueryTransformer < Parslet::Transform
   ).freeze
 
   class Query
+    attr_reader :keywords
+
     def initialize(clauses, options = {})
       raise ArgumentError if options[:current_account].nil?
 
@@ -20,6 +22,7 @@ class SearchQueryTransformer < Parslet::Transform
       @options = options
 
       flags_from_clauses!
+      keywords_from_clauses!
     end
 
     def request
@@ -42,6 +45,10 @@ class SearchQueryTransformer < Parslet::Transform
       @flags = clauses_by_operator.fetch(:flag, []).to_h { |clause| [clause.prefix, clause.term] }
     end
 
+    def keywords_from_clauses!
+      @keywords = must_clauses.flat_map(&:keywords).uniq
+    end
+
     def must_clauses
       clauses_by_operator.fetch(:must, [])
     end
@@ -128,6 +135,10 @@ class SearchQueryTransformer < Parslet::Transform
         { multi_match: { type: 'most_fields', query: @term, fields: ['text', 'text.stemmed'], operator: 'and' } }
       end
     end
+
+    def keywords
+      @term.split
+    end
   end
 
   class PhraseClause
@@ -141,6 +152,10 @@ class SearchQueryTransformer < Parslet::Transform
     def to_query
       { match_phrase: { text: { query: @phrase } } }
     end
+
+    def keywords
+      @phrase.split
+    end
   end
 
   class PrefixClause
@@ -193,6 +208,10 @@ class SearchQueryTransformer < Parslet::Transform
       end
     end
 
+    def keywords
+      []
+    end
+
     private
 
     def account_id_from_term(term)

app/services/statuses_search_service.rb

@@ -25,6 +25,8 @@ class StatusesSearchService < BaseService
   private
 
   def status_search_results
+    return [] if contains_forbidden_terms?
+
     request             = parsed_query.request
     results             = request.collapse(field: :id).order(id: { order: :desc }).limit(@limit).offset(@offset).objects.compact
     account_ids         = results.map(&:account_id)
@@ -37,7 +39,7 @@ class StatusesSearchService < BaseService
   end
 
   def parsed_query
-    SearchQueryTransformer.new.apply(SearchQueryParser.new.parse(@query), current_account: @account)
+    @parsed_query ||= SearchQueryTransformer.new.apply(SearchQueryParser.new.parse(@query), current_account: @account)
   end
 
   def convert_deprecated_options!
@@ -60,4 +62,8 @@ class StatusesSearchService < BaseService
 
     @query = "#{@query} #{syntax_options.join(' ')}".strip if syntax_options.any?
   end
+
+  def contains_forbidden_terms?
+    Tag.where(usable: false).matching_name(parsed_query.keywords).exists?
+  end
 end

app/services/tag_search_service.rb

@@ -41,7 +41,7 @@ class TagSearchService < BaseService
 
     normalized_query = Tag.normalize(@query)
     exact_match = results.find { |tag| tag.name.downcase == normalized_query }
-    exact_match ||= Tag.find_normalized(normalized_query)
+    exact_match ||= Tag.listable.find_normalized(normalized_query)
     unless exact_match.nil?
       results.delete(exact_match)
       results = [exact_match] + results