[Fix rubocop#305] Fix crash in Rails/MatchRoute cop when via opti…

…on is a variable

Closes rubocop#305

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 * [#297](https://github.com/rubocop-hq/rubocop-rails/pull/297): Handle an upstream Ruby issue where the DidYouMean module is not available, which would break the `Rails/UnknownEnv` cop. ([@taylorthurlow][])
 * [#300](https://github.com/rubocop-hq/rubocop-rails/issues/300): Fix `Rails/RenderInline` error on variable key in render options. ([@tejasbubane][])
+* [#305](https://github.com/rubocop-hq/rubocop-rails/issues/305): Fix crash in `Rails/MatchRoute` cop when via option is a variable. ([@tejasbubane][])
 
 ### Changes
 

lib/rubocop/cop/rails/match_route.rb

@@ -77,6 +77,8 @@ def extract_via(node)
             [via.value]
           elsif via.array_type?
             via.values.map(&:value)
+          else
+            []
           end
         end
 

spec/rubocop/cop/rails/match_route_spec.rb

@@ -63,6 +63,21 @@
     RUBY
   end
 
+  it 'registers an offense when using match with string interpolation' do
+    expect_offense(<<~'RUBY')
+      routes.draw do
+        match "#{resource}/:action/:id", via: [:put]
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `put` instead of `match` to define a route.
+      end
+    RUBY
+
+    expect_correction(<<~'RUBY')
+      routes.draw do
+        put "#{resource}/:action/:id"
+      end
+    RUBY
+  end
+
   it 'does not register an offense when not within routes' do
     expect_no_offenses(<<~RUBY)
       match 'photos/:id', to: 'photos#show', via: :get
@@ -92,4 +107,12 @@
       end
     RUBY
   end
+
+  it 'does not register an offense when via is a variable' do
+    expect_no_offenses(<<~'RUBY')
+      routes.draw do
+        match ':controller/:action/:id', via: method
+      end
+    RUBY
+  end
 end