Move String#undent to compat.

Library/Homebrew/compat.rb

@@ -26,3 +26,4 @@ require "compat/ENV/shared"
 require "compat/ENV/std"
 require "compat/ENV/super"
 require "compat/utils/shell"
+require "compat/extend/string"

Library/Homebrew/compat/extend/string.rb

@@ -0,0 +1,18 @@
+class String
+  def undent
+    gsub(/^[ \t]{#{(slice(/^[ \t]+/) || '').length}}/, "")
+  end
+  alias unindent undent
+
+  # eg:
+  #   if foo then <<-EOS.undent_________________________________________________________72
+  #               Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do
+  #               eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad
+  #               minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip
+  #               ex ea commodo consequat. Duis aute irure dolor in reprehenderit in
+  #               voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur
+  #               sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt
+  #               mollit anim id est laborum.
+  #               EOS
+  alias undent_________________________________________________________72 undent
+end

Library/Homebrew/extend/string.rb

@@ -2,23 +2,6 @@
 require_relative "../vendor/backports/string"
 
 class String
-  def undent
-    gsub(/^[ \t]{#{(slice(/^[ \t]+/) || '').length}}/, "")
-  end
-  alias unindent undent
-
-  # eg:
-  #   if foo then <<~EOS_________________________________________________________72
-  #               Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do
-  #               eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad
-  #               minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip
-  #               ex ea commodo consequat. Duis aute irure dolor in reprehenderit in
-  #               voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur
-  #               sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt
-  #               mollit anim id est laborum.
-  #               EOS
-  alias undent_________________________________________________________72 undent
-
   # String.chomp, but if result is empty: returns nil instead.
   # Allows `chuzzle || foo` short-circuits.
   def chuzzle

Library/Homebrew/test/string_spec.rb

@@ -1,41 +1,5 @@
 require "extend/string"
 
-describe String do
-  describe "#undent" do
-    it "removes leading whitespace, taking the first line as reference" do
-      string = <<-EOS.unindent
-                hi
-                ........my friend over
-                  there
-      EOS
-
-      expect(string).to eq("hi\n........my friend over\n  there\n")
-    end
-
-    it "removes nothing if the text is not indented" do
-      string = <<-EOS.unindent
-        hi
-        I'm not indented
-      EOS
-
-      expect(string).to eq("hi\nI'm not indented\n")
-    end
-
-    it "can be nested" do
-      nested_string = <<~EOS
-        goodbye
-      EOS
-
-      string = <<~EOS
-        hello
-        #{nested_string}
-      EOS
-
-      expect(string).to eq("hello\ngoodbye\n\n")
-    end
-  end
-end
-
 describe StringInreplaceExtension do
   subject { string.extend(described_class) }
   let(:string) { "foobar" }