From 06f9333148dd6cab52eeb34bc4adbfb00674f57b Mon Sep 17 00:00:00 2001
From: Koichi ITO <koic.ito@gmail.com>
Date: Tue, 30 Jul 2019 02:27:38 +0900
Subject: [PATCH] Fix an error for `Performance/RedundantMerge`

Follow up https://github.com/rubocop-hq/rubocop-performance/pull/68#issuecomment-516072052.

#68 didn't solve an issue #67 with `Performance/RedundantMerge`.
This PR is corrected by adding a reproduction test.
---
 CHANGELOG.md                                       |  4 ++++
 lib/rubocop/cop/performance/redundant_merge.rb     |  2 +-
 .../cop/performance/redundant_merge_spec.rb        | 14 ++++++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5b09db6a49..4e0da22590 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### Bug fixes
+
+* [#74](https://github.com/rubocop-hq/rubocop-performance/pull/74): Fix an error for `Performance/RedundantMerge` when `MaxKeyValuePairs` option is set to `null`. ([@koic][])
+
 ## 1.4.1 (2019-07-29)
 
 ### Bug fixes
diff --git a/lib/rubocop/cop/performance/redundant_merge.rb b/lib/rubocop/cop/performance/redundant_merge.rb
index 45b610846c..0ccb54eeea 100644
--- a/lib/rubocop/cop/performance/redundant_merge.rb
+++ b/lib/rubocop/cop/performance/redundant_merge.rb
@@ -132,7 +132,7 @@ def indent_width
         end
 
         def max_key_value_pairs
-          Integer(cop_config['MaxKeyValuePairs']) || 2
+          Integer(cop_config['MaxKeyValuePairs'] || 2)
         end
 
         # A utility class for checking the use of values within an
diff --git a/spec/rubocop/cop/performance/redundant_merge_spec.rb b/spec/rubocop/cop/performance/redundant_merge_spec.rb
index b8c2b65138..5c2a281e71 100644
--- a/spec/rubocop/cop/performance/redundant_merge_spec.rb
+++ b/spec/rubocop/cop/performance/redundant_merge_spec.rb
@@ -261,4 +261,18 @@
       RUBY
     end
   end
+
+  context 'when MaxKeyValuePairs is set to nil' do
+    let(:cop_config) do
+      { 'MaxKeyValuePairs' => nil }
+    end
+
+    it 'does not raise `TypeError`' do
+      expect_offense(<<~RUBY)
+        hash = {}
+        hash.merge!(a: 1, b: 2)
+        ^^^^^^^^^^^^^^^^^^^^^^^ Use `hash[:a] = 1; hash[:b] = 2` instead of `hash.merge!(a: 1, b: 2)`.
+      RUBY
+    end
+  end
 end