uninstall: refuse when dependants still installed

Closes #934.

1 files changed, 9 insertions, 0 deletions

diff --git a/Library/Homebrew/cmd/uninstall.rb b/Library/Homebrew/cmd/uninstall.rb
index 8bcfc31fb..3d40c2350 100644
--- a/Library/Homebrew/cmd/uninstall.rb
+++ b/Library/Homebrew/cmd/uninstall.rb
@@ -16,6 +16,15 @@ module Homebrew
 
     if !ARGV.force?
       ARGV.kegs.each do |keg|
+        dependants = keg.installed_dependants
+        if dependants.any?
+          dependants_output = dependants.map { |k| "#{k.name} #{k.version}" }.join(", ")
+          conjugation = dependants.count == 1 ? "is" : "are"
+          ofail "Refusing to uninstall #{keg} because it is required by #{dependants_output}, which #{conjugation} currently installed."
+          puts "Remove it anyway with `brew uninstall --force #{keg.name}`."
+          next
+        end
+
         keg.lock do
           puts "Uninstalling #{keg}... (#{keg.abv})"
           keg.unlink