diff --git a/Library/.rubocop_todo.yml b/Library/.rubocop_todo.yml
index 80fa07aabeffba1cbea2947cbe0d1b6c85a9e0ea..4819be65a2dfb4b802e99c3c56f9cab3febc2bb0 100644
--- a/Library/.rubocop_todo.yml
+++ b/Library/.rubocop_todo.yml
@@ -119,13 +119,6 @@ Style/ConstantName:
   Exclude:
     - 'Homebrew/os/mac.rb'
 
-# Offense count: 1
-# Configuration parameters: EnforcedStyle, SupportedStyles.
-# SupportedStyles: format, sprintf, percent
-Style/FormatString:
-  Exclude:
-    - 'Homebrew/formula.rb'
-
 # Offense count: 13
 # Configuration parameters: AllowedVariables.
 Style/GlobalVars:
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 7a5584cdfe8b38daad66f9340f3aae152e562aa6..ef10e67a2ba7a491685ac667b17c61e8a062ed37 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -1668,7 +1668,7 @@ class Formula
 
     @exec_count ||= 0
     @exec_count += 1
-    logfn = "#{logs}/#{active_log_prefix}%02d.%s" % [@exec_count, File.basename(cmd).split(" ").first]
+    logfn = format("#{logs}/#{active_log_prefix}%02d.%s", @exec_count, File.basename(cmd).split(" ").first)
     logs.mkpath
 
     File.open(logfn, "w") do |log|