Change empty search requests to return a HTTP 400 error (#40214)

app/controllers/api/v2/search_controller.rb

@@ -13,14 +13,13 @@ class Api::V2::SearchController < Api::BaseController
     before_action :query_pagination_error, if: :pagination_requested?
     before_action :remote_resolve_error, if: :remote_resolve_requested?
   end
+
   before_action :require_valid_pagination_options!
   before_action :handle_fasp_requests
 
   def index
     @search = Search.new(search_results)
     render json: @search, serializer: REST::SearchSerializer
-  rescue Mastodon::SyntaxError
-    unprocessable_content
   rescue ActiveRecord::RecordNotFound
     not_found
   end

app/controllers/concerns/api/error_handling.rb

@@ -45,7 +45,7 @@ module Api::ErrorHandling
       render json: { error: I18n.t('errors.429') }, status: 429
     end
 
-    rescue_from ActionController::ParameterMissing, Mastodon::InvalidParameterError do |e|
+    rescue_from ActionController::ParameterMissing, Mastodon::InvalidParameterError, SearchQueryTransformer::QueryError do |e|
       render json: { error: e.to_s }, status: 400
     end
   end

app/lib/search_query_transformer.rb

@@ -12,6 +12,9 @@ class SearchQueryTransformer < Parslet::Transform
     in
   ).freeze
 
+  class TransformerError < StandardError; end
+  class QueryError < StandardError; end
+
   class Query
     def initialize(clauses, options = {})
       raise ArgumentError if options[:current_account].nil?
@@ -37,7 +40,7 @@ class SearchQueryTransformer < Parslet::Transform
 
     def validate_clauses!
       # At least one clause should be a positive match unless searching within the library
-      raise 'Empty query not supported' if @flags['in'] != 'library' && (must_clauses + filter_clauses).none? { |clause| clause.is_a?(TermClause) && clause.term.present? }
+      raise QueryError, 'At least one keyword or phrase is required' if @flags['in'] != 'library' && (must_clauses + filter_clauses).none? { |clause| clause.is_a?(TermClause) && clause.term.present? }
     end
 
     def clauses_by_operator
@@ -113,7 +116,7 @@ class SearchQueryTransformer < Parslet::Transform
         when '-'
           :must_not
         else
-          raise "Unknown operator: #{str}"
+          raise TransformerError, "Unknown operator: #{str}"
         end
       end
     end
@@ -182,7 +185,7 @@ class SearchQueryTransformer < Parslet::Transform
         @operator = :flag
         @term = term
       else
-        raise "Unknown prefix: #{prefix}"
+        raise TransformerError, "Unknown prefix: #{prefix}"
       end
     end
 
@@ -244,7 +247,7 @@ class SearchQueryTransformer < Parslet::Transform
     elsif clause[:phrase]
       PhraseClause.new(operator, term)
     else
-      raise "Unexpected clause type: #{clause}"
+      raise TransformerError, "Unexpected clause type: #{clause}"
     end
   end
 

lib/exceptions.rb

@@ -10,7 +10,6 @@ module Mastodon
   class StreamValidationError < ValidationError; end
   class RaceConditionError < Error; end
   class RateLimitExceededError < Error; end
-  class SyntaxError < Error; end
   class InvalidParameterError < Error; end
   class SignatureVerificationError < Error; end
   class MalformedHeaderError < Error; end

spec/lib/search_query_transformer_spec.rb

@@ -45,7 +45,7 @@ RSpec.describe SearchQueryTransformer do
       let(:query) { '-hello' }
 
       it 'raises an exception' do
-        expect { subject }.to raise_error(RuntimeError)
+        expect { subject }.to raise_error(SearchQueryTransformer::QueryError)
       end
     end
 
@@ -53,7 +53,7 @@ RSpec.describe SearchQueryTransformer do
       let(:query) { 'after:0000' }
 
       it 'raises an exception' do
-        expect { subject }.to raise_error(RuntimeError)
+        expect { subject }.to raise_error(SearchQueryTransformer::QueryError)
       end
     end
 
@@ -61,7 +61,7 @@ RSpec.describe SearchQueryTransformer do
       let(:query) { 'before:9999' }
 
       it 'raises an exception' do
-        expect { subject }.to raise_error(RuntimeError)
+        expect { subject }.to raise_error(SearchQueryTransformer::QueryError)
       end
     end
 
@@ -69,7 +69,7 @@ RSpec.describe SearchQueryTransformer do
       let(:query) { 'is:reply' }
 
       it 'raises an exception' do
-        expect { subject }.to raise_error(RuntimeError)
+        expect { subject }.to raise_error(SearchQueryTransformer::QueryError)
       end
     end
 
@@ -77,7 +77,7 @@ RSpec.describe SearchQueryTransformer do
       let(:query) { 'is:reply " "' }
 
       it 'raises an exception' do
-        expect { subject }.to raise_error(RuntimeError)
+        expect { subject }.to raise_error(SearchQueryTransformer::QueryError)
       end
     end
 

spec/requests/api/v2/search_spec.rb

@@ -93,12 +93,12 @@ RSpec.describe 'Search API' do
       end
 
       context 'when search raises syntax error' do
-        before { allow(Search).to receive(:new).and_raise(Mastodon::SyntaxError) }
+        before { allow(Search).to receive(:new).and_raise(SearchQueryTransformer::QueryError) }
 
-        it 'returns http unprocessable_content' do
+        it 'returns http bad request' do
           get '/api/v2/search', headers: headers, params: params
 
-          expect(response).to have_http_status(422)
+          expect(response).to have_http_status(400)
           expect(response.content_type)
             .to start_with('application/json')
         end