From bd4aaac96b1f08d59a8e208095ac56ff446608df Mon Sep 17 00:00:00 2001
From: Jack Nagel <jacknagel@gmail.com>
Date: Tue, 9 Apr 2013 19:40:08 -0500
Subject: [PATCH] Check existence rather than rescue exceptions

---
 Library/Homebrew/formula.rb           |  2 +-
 Library/Homebrew/test/test_formula.rb | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index c994202e3e..a6305eaaff 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -80,7 +80,7 @@ class Formula
 
   # if the dir is there, but it's empty we consider it not installed
   def installed?
-    installed_prefix.children.length > 0 rescue false
+    (dir = installed_prefix).directory? && dir.children.length > 0
   end
 
   def pinable?
diff --git a/Library/Homebrew/test/test_formula.rb b/Library/Homebrew/test/test_formula.rb
index 918ff714fd..bdeb398d8d 100644
--- a/Library/Homebrew/test/test_formula.rb
+++ b/Library/Homebrew/test/test_formula.rb
@@ -14,6 +14,22 @@ class FormulaTests < Test::Unit::TestCase
     assert_kind_of Pathname, f.prefix
   end
 
+  def test_installed?
+    f = TestBall.new
+    f.stubs(:installed_prefix).returns(stub(:directory? => false))
+    assert !f.installed?
+
+    f.stubs(:installed_prefix).returns(
+      stub(:directory? => true, :children => [])
+    )
+    assert !f.installed?
+
+    f.stubs(:installed_prefix).returns(
+      stub(:directory? => true, :children => [stub])
+    )
+    assert f.installed?
+  end
+
   def test_class_naming
     assert_equal 'ShellFm', Formula.class_s('shell.fm')
     assert_equal 'Fooxx', Formula.class_s('foo++')