From b792a5fd2066d5952aeed4ea4024997e0af21282 Mon Sep 17 00:00:00 2001
From: Nanda H Krishna <me@nandahkrishna.com>
Date: Sat, 18 Mar 2023 10:44:35 -0400
Subject: [PATCH] utils/github/actions: add `format_multiline_string` method

---
 Library/Homebrew/utils/github/actions.rb | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/Library/Homebrew/utils/github/actions.rb b/Library/Homebrew/utils/github/actions.rb
index c255dec4a0..84e447cd0c 100644
--- a/Library/Homebrew/utils/github/actions.rb
+++ b/Library/Homebrew/utils/github/actions.rb
@@ -1,6 +1,7 @@
 # typed: true
 # frozen_string_literal: true
 
+require "securerandom"
 require "utils/tty"
 
 module GitHub
@@ -18,6 +19,24 @@ module GitHub
             .gsub("\r", "%0D")
     end
 
+    sig { params(name: String, value: String).returns(String) }
+    def self.format_multiline_string(name, value)
+      # Format multiline strings for environment files
+      # See https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#multiline-strings
+
+      delimiter = "ghadelimiter_#{SecureRandom.uuid}"
+
+      if name.include?(delimiter) || value.include?(delimiter)
+        raise Error, "`name` and `value` must not contain the delimiter"
+      end
+
+      <<~EOS
+        #{name}<<#{delimiter}
+        #{value}
+        #{delimiter}
+      EOS
+    end
+
     # Helper class for formatting annotations on GitHub Actions.
     class Annotation
       extend T::Sig
@@ -85,5 +104,9 @@ module GitHub
         @file.descend.next.to_s != ".."
       end
     end
+
+    # Generic GitHub Actions error.
+    class Error < RuntimeError
+    end
   end
 end