From 3d559fa79641735193636cbf6240c082e6ca171c Mon Sep 17 00:00:00 2001
From: Alyssa Ross <hi@alyssa.is>
Date: Wed, 14 Sep 2016 23:18:55 +0100
Subject: [PATCH] Add Formula#installed_alias_path

---
 Library/Homebrew/formula.rb           | 16 ++++++++++++----
 Library/Homebrew/test/test_formula.rb | 26 ++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 599b493920..f2da6fbc86 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -60,7 +60,7 @@ class Formula
   # e.g. `this-formula`
   attr_reader :name
 
-  # The name specified when installing this {Formula}.
+  # The name that was used to identify this {Formula}.
   # Could be the name of the {Formula}, or an alias.
   # e.g. `another-name-for-this-formula`
   attr_reader :alias_path
@@ -228,7 +228,15 @@ class Formula
 
   public
 
-  # The path that was specified to find/install this formula.
+  # The alias path that was used to install this formula, if present.
+  # Can differ from alias_path, which is the alias used to find the formula,
+  # and is specified to this instance.
+  def installed_alias_path
+    path = build.source["path"] if build.is_a?(Tab)
+    path if path =~ %r{#{HOMEBREW_TAP_DIR_REGEX}/Aliases}
+  end
+
+  # The path that was specified to find this formula.
   def specified_path
     alias_path || path
   end
@@ -503,13 +511,13 @@ class Formula
     prefix.parent
   end
 
-  # All of current installed prefix directories.
+  # All currently installed prefix directories.
   # @private
   def installed_prefixes
     rack.directory? ? rack.subdirs : []
   end
 
-  # All of current installed kegs.
+  # All currently installed kegs.
   # @private
   def installed_kegs
     installed_prefixes.map { |dir| Keg.new(dir) }
diff --git a/Library/Homebrew/test/test_formula.rb b/Library/Homebrew/test/test_formula.rb
index 7c09e765f2..2eb64ebb67 100644
--- a/Library/Homebrew/test/test_formula.rb
+++ b/Library/Homebrew/test/test_formula.rb
@@ -248,6 +248,32 @@ class FormulaTests < Homebrew::TestCase
     assert_nil Testball.new <=> Object.new
   end
 
+  def test_alias_paths_with_build_options
+    alias_path = CoreTap.instance.alias_dir/"another_name"
+    f = formula(:alias_path => alias_path) { url "foo-1.0" }
+    f.build = BuildOptions.new({}, {})
+    assert_equal alias_path, f.alias_path
+    assert_nil f.installed_alias_path
+  end
+
+  def test_alias_paths_with_tab_with_non_alias_source_path
+    alias_path = CoreTap.instance.alias_dir/"another_name"
+    source_path = CoreTap.instance.formula_dir/"another_other_name"
+    f = formula(:alias_path => alias_path) { url "foo-1.0" }
+    f.build = Tab.new(:source => { "path" => source_path.to_s })
+    assert_equal alias_path, f.alias_path
+    assert_nil f.installed_alias_path
+  end
+
+  def test_alias_paths_with_tab_with_alias_source_path
+    alias_path = CoreTap.instance.alias_dir/"another_name"
+    source_path = CoreTap.instance.alias_dir/"another_other_name"
+    f = formula(:alias_path => alias_path) { url "foo-1.0" }
+    f.build = Tab.new(:source => { "path" => source_path.to_s })
+    assert_equal alias_path, f.alias_path
+    assert_equal source_path.to_s, f.installed_alias_path
+  end
+
   def test_formula_spec_integration
     f = formula do
       homepage "http://example.com"