Manage Requirements using ComparableSet

ComparableSet only allows a single object of a given class,
choosing the object with the greatest value. This was mainly created
for Requirements, so that, e.g., two X11Dependencies of differing
strictness don't both end up in the same requirement set.

Fixes Homebrew/homebrew#15240.

1 files changed, 4 insertions, 3 deletions

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index d23aeea71..8f63cd705 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -6,6 +6,7 @@ require 'bottles'
 require 'patches'
 require 'compilers'
 require 'build_environment'
+require 'extend/set'
 
 
 class Formula
@@ -455,9 +456,9 @@ class Formula
   end
 
   def recursive_requirements
-    reqs = recursive_deps.map { |dep| dep.requirements }.to_set
-    reqs << requirements
-    reqs.flatten
+    reqs = ComparableSet.new
+    recursive_deps.each { |dep| reqs.merge dep.requirements }
+    reqs.merge requirements
   end
 
   def to_hash