Merge pull request #476 from crystal-ameba/fix-457

Ignore block parameter names starting with `_`

spec/ameba/rule/naming/block_parameter_name_spec.cr

@@ -3,7 +3,7 @@ require "../../../spec_helper"
 module Ameba::Rule::Naming
   subject = BlockParameterName.new
     .tap(&.min_name_length = 3)
-    .tap(&.allowed_names = %w[_ e i j k v])
+    .tap(&.allowed_names = %w[e i j k v])
 
   describe BlockParameterName do
     it "passes if block parameter name matches #allowed_names" do
@@ -14,6 +14,12 @@ module Ameba::Rule::Naming
       end
     end
 
+    it "passes if block parameter name starts with '_'" do
+      expect_no_issues subject, <<-CRYSTAL
+        %w[].each { |_, _foo, _bar| }
+        CRYSTAL
+    end
+
     it "fails if block parameter name doesn't match #allowed_names" do
       expect_issue subject, <<-CRYSTAL
         %w[].each { |x| }

src/ameba/rule/naming/block_parameter_name.cr

@@ -28,7 +28,7 @@ module Ameba::Rule::Naming
       description "Disallows non-descriptive block parameter names"
       min_name_length 3
       allow_names_ending_in_numbers true
-      allowed_names %w[_ e i j k v x y ex io ws op tx id ip k1 k2 v1 v2]
+      allowed_names %w[e i j k v x y ex io ws op tx id ip k1 k2 v1 v2]
       forbidden_names %w[]
     end
 
@@ -42,7 +42,7 @@ module Ameba::Rule::Naming
 
     private def valid_name?(name)
       return true if name.blank? # TODO: handle unpacked variables
-      return true if name.in?(allowed_names)
+      return true if name.starts_with?('_') || name.in?(allowed_names)
 
       return false if name.in?(forbidden_names)
       return false if name.size < min_name_length