From c8e705823f544fe88e2e112cc1a5a27731dfd105 Mon Sep 17 00:00:00 2001
From: Genadi Samokovarov <gsamokovarov@gmail.com>
Date: Thu, 25 Mar 2021 14:10:22 +0200
Subject: [PATCH] Parenthesized forwarded args in
 Style/MethodCallWithArgsParentheses

The new-style arguments delegation included in Ruby 2.7 and expanded in
Ruby 3.0 is required to be parenthesized, since the syntax is clashing
with the endless `start...` range, which can be started with `start ...`
as well. Currently, the most iffy cop of them all is issuing offenses
for:

```ruby
def delegated_call(...)
  @proxy.call(...)
             ^^^^^ Omit parentheses for method calls with arguments.
end
```

Removing the parens will start an endless range with the beginning
being the result of the method call without arguments. See the parse
trees below for more details:

```bash
-> ruby-parse -e "def foo(...); bar(...); end"
(def :foo
  (args
    (forward-arg))
  (send nil :bar
    (forwarded-args)))

-> ruby-parse -e "def foo(...); bar ...; end"
(def :foo
  (args
    (forward-arg))
  (erange
    (send nil :bar) nil))

-> ruby-parse -e "def foo(...); bar...; end"
(def :foo
  (args
    (forward-arg))
  (erange
    (send nil :bar) nil))
```

We don't want that so allow the parens and leave this gotcha to the poor
developer that's gonna run into it.
---
 ...style_method_call_with_args_parentheses.md |  1 +
 .../omit_parentheses.rb                       |  8 +++-----
 .../method_call_with_args_parentheses_spec.rb | 20 +++++++++++++++++++
 3 files changed, 24 insertions(+), 5 deletions(-)
 create mode 100644 changelog/fix_parentheses_in_forwarded_args_for_style_method_call_with_args_parentheses.md

diff --git a/changelog/fix_parentheses_in_forwarded_args_for_style_method_call_with_args_parentheses.md b/changelog/fix_parentheses_in_forwarded_args_for_style_method_call_with_args_parentheses.md
new file mode 100644
index 00000000000..535227f8023
--- /dev/null
+++ b/changelog/fix_parentheses_in_forwarded_args_for_style_method_call_with_args_parentheses.md
@@ -0,0 +1 @@
+* [#9637](https://github.com/rubocop/rubocop/issues/9637): Allow parentheses for forwarded args in `Style/MethodCallWithArgsParentheses`'s `omit_parentheses` style to avoid endless range ambiguity. ([@gsamokovarov][])
diff --git a/lib/rubocop/cop/style/method_call_with_args_parentheses/omit_parentheses.rb b/lib/rubocop/cop/style/method_call_with_args_parentheses/omit_parentheses.rb
index 42e8dd863c9..b13e9da9536 100644
--- a/lib/rubocop/cop/style/method_call_with_args_parentheses/omit_parentheses.rb
+++ b/lib/rubocop/cop/style/method_call_with_args_parentheses/omit_parentheses.rb
@@ -5,7 +5,7 @@ module Cop
     module Style
       class MethodCallWithArgsParentheses
         # Style omit_parentheses
-        # rubocop:disable Metrics/ModuleLength
+        # rubocop:disable Metrics/ModuleLength, Metrics/CyclomaticComplexity
         module OmitParentheses
           TRAILING_WHITESPACE_REGEX = /\s+\Z/.freeze
           OMIT_MSG = 'Omit parentheses for method calls with arguments.'
@@ -13,7 +13,6 @@ module OmitParentheses
 
           private
 
-          # rubocop:disable Metrics/CyclomaticComplexity
           def omit_parentheses(node)
             return unless node.parenthesized?
             return if inside_endless_method_def?(node)
@@ -27,7 +26,6 @@ def omit_parentheses(node)
               auto_correct(corrector, node)
             end
           end
-          # rubocop:enable Metrics/CyclomaticComplexity
 
           def auto_correct(corrector, node)
             if parentheses_at_the_end_of_multiline_call?(node)
@@ -114,7 +112,7 @@ def call_with_ambiguous_arguments?(node)
               call_as_argument_or_chain?(node) ||
               hash_literal_in_arguments?(node) ||
               node.descendants.any? do |n|
-                ambigious_literal?(n) || logical_operator?(n) ||
+                n.forwarded_args_type? || ambigious_literal?(n) || logical_operator?(n) ||
                   call_with_braced_block?(n)
               end
           end
@@ -190,7 +188,7 @@ def inside_string_interpolation?(node)
             node.ancestors.drop_while { |a| !a.begin_type? }.any?(&:dstr_type?)
           end
         end
-        # rubocop:enable Metrics/ModuleLength
+        # rubocop:enable Metrics/ModuleLength, Metrics/CyclomaticComplexity
       end
     end
   end
diff --git a/spec/rubocop/cop/style/method_call_with_args_parentheses_spec.rb b/spec/rubocop/cop/style/method_call_with_args_parentheses_spec.rb
index 1f099178d9f..47424de2783 100644
--- a/spec/rubocop/cop/style/method_call_with_args_parentheses_spec.rb
+++ b/spec/rubocop/cop/style/method_call_with_args_parentheses_spec.rb
@@ -361,6 +361,26 @@ module Foo
 
     it_behaves_like 'endless methods', omit: true
 
+    context 'forwarded arguments in 2.7', :ruby27 do
+      it 'accepts parens for forwarded arguments' do
+        expect_no_offenses(<<~RUBY)
+          def delegated_call(...)
+            @proxy.call(...)
+          end
+        RUBY
+      end
+    end
+
+    context 'forwarded arguments in 3.0', :ruby30 do
+      it 'accepts parens for forwarded arguments' do
+        expect_no_offenses(<<~RUBY)
+          def method_missing(name, ...)
+            @proxy.call(name, ...)
+          end
+        RUBY
+      end
+    end
+
     it 'register an offense for parens in method call without args' do
       trailing_whitespace = ' '