Move brew-leaves into core

Closes Homebrew/homebrew#24371.

1 files changed, 29 insertions, 0 deletions

diff --git a/Library/Homebrew/cmd/leaves.rb b/Library/Homebrew/cmd/leaves.rb
new file mode 100644
index 000000000..bffa332d6
--- /dev/null
+++ b/Library/Homebrew/cmd/leaves.rb
@@ -0,0 +1,29 @@
+require 'formula'
+require 'tab'
+require 'set'
+
+module Homebrew extend self
+  def leaves
+    installed = Formula.installed
+    deps_of_installed = Set.new
+
+    installed.each do |f|
+      deps = []
+
+      f.deps.each do |dep|
+        if dep.optional? || dep.recommended?
+          tab = Tab.for_formula(f)
+          deps << dep.name if tab.with?(dep.name)
+        else
+          deps << dep.name
+        end
+      end
+
+      deps_of_installed.merge(deps)
+    end
+
+    installed.each do |f|
+      puts f.name unless deps_of_installed.include? f.name
+    end
+  end
+end