From 971951314a843256a26352f70e3f3d69e01e216b Mon Sep 17 00:00:00 2001
From: Koichi ITO <koic.ito@gmail.com>
Date: Fri, 29 Sep 2023 21:38:42 +0900
Subject: [PATCH] Add new "Single-line `do`...`end` block" rule

Follow up https://github.com/rubocop/rubocop/pull/12227#discussion_r1341024676

This PR adds new "Single-line `do`...`end` block" rule.

Use multi-line `do`...`end` block instead of single-line `do`...`end` block.

```ruby
# bad
foo do |arg| bar(arg) end

# good
foo do |arg|
  bar(arg)
end

# bad
->(arg) do bar(arg) end

# good
->(arg) { bar(arg) }
```
---
 README.adoc | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/README.adoc b/README.adoc
index 37780243..eda68c19 100644
--- a/README.adoc
+++ b/README.adoc
@@ -2618,6 +2618,27 @@ names.select { |name| name.start_with?('S') }.map(&:upcase)
 
 Some will argue that multi-line chaining would look OK with the use of {...}, but they should ask themselves - is this code really readable and can the blocks' contents be extracted into nifty methods?
 
+=== Single-line `do`...`end` block [[single-line-do-end-block]]
+
+Use multi-line `do`...`end` block instead of single-line `do`...`end` block.
+
+[source,ruby]
+----
+# bad
+foo do |arg| bar(arg) end
+
+# good
+foo do |arg|
+  bar(arg)
+end
+
+# bad
+->(arg) do bar(arg) end
+
+# good
+->(arg) { bar(arg) }
+----
+
 === Explicit Block Argument [[block-argument]]
 
 Consider using explicit block argument to avoid writing block literal that just passes its arguments to another block.