14 files changed, 96 insertions, 36 deletions
diff --git a/Library/Homebrew/cask/lib/hbc/cli/style.rb b/Library/Homebrew/cask/lib/hbc/cli/style.rb
index cdcc135b8..d3e44382d 100644
--- a/Library/Homebrew/cask/lib/hbc/cli/style.rb
+++ b/Library/Homebrew/cask/lib/hbc/cli/style.rb
@@ -23,12 +23,10 @@ module Hbc
         $CHILD_STATUS.success?
       end
 
-      RUBOCOP_CASK_VERSION = "~> 0.10.6".freeze
-
       def install_rubocop
         Utils.capture_stderr do
           begin
-            Homebrew.install_gem_setup_path! "rubocop-cask", RUBOCOP_CASK_VERSION, "rubocop"
+            Homebrew.install_gem_setup_path! "rubocop-cask", HOMEBREW_RUBOCOP_CASK_VERSION, "rubocop"
           rescue SystemExit
             raise CaskError, Tty.strip_ansi($stderr.string).chomp.sub(/\AError: /, "")
           end
diff --git a/Library/Homebrew/cask/spec/cask/cli/style_spec.rb b/Library/Homebrew/cask/spec/cask/cli/style_spec.rb
index b0d34576a..106bfbb44 100644
--- a/Library/Homebrew/cask/spec/cask/cli/style_spec.rb
+++ b/Library/Homebrew/cask/spec/cask/cli/style_spec.rb
@@ -1,4 +1,6 @@
 require "English"
+require "open3"
+require "rubygems"
 
 describe Hbc::CLI::Style do
   let(:args) { [] }
@@ -77,6 +79,20 @@ describe Hbc::CLI::Style do
         expect { subject }.to raise_error(Hbc::CaskError)
       end
     end
+
+    context "version" do
+      it "matches `HOMEBREW_RUBOCOP_VERSION`" do
+        stdout, status = Open3.capture2("gem", "dependency", "rubocop-cask", "--version", HOMEBREW_RUBOCOP_CASK_VERSION, "--pipe", "--remote")
+
+        expect(status).to be_a_success
+
+        requirement = Gem::Requirement.new(stdout.scan(/rubocop --version '(.*)'/).flatten.first)
+        version = Gem::Version.new(HOMEBREW_RUBOCOP_VERSION)
+
+        expect(requirement).not_to be_none
+        expect(requirement).to be_satisfied_by(version)
+      end
+    end
   end
 
   describe "#cask_paths" do
diff --git a/Library/Homebrew/cmd/--prefix.rb b/Library/Homebrew/cmd/--prefix.rb
index f6e7d2ee2..956ab0403 100644
--- a/Library/Homebrew/cmd/--prefix.rb
+++ b/Library/Homebrew/cmd/--prefix.rb
@@ -11,7 +11,9 @@ module Homebrew
     if ARGV.named.empty?
       puts HOMEBREW_PREFIX
     else
-      puts ARGV.resolved_formulae.map(&:installed_prefix)
+      puts ARGV.resolved_formulae.map { |f|
+        f.opt_prefix.exist? ? f.opt_prefix : f.installed_prefix
+      }
     end
   end
 end
diff --git a/Library/Homebrew/cmd/style.rb b/Library/Homebrew/cmd/style.rb
index 586c6da6b..3d12561c1 100644
--- a/Library/Homebrew/cmd/style.rb
+++ b/Library/Homebrew/cmd/style.rb
@@ -47,7 +47,7 @@ module Homebrew
 
   def check_style_impl(files, output_type, options = {})
     fix = options[:fix]
-    Homebrew.install_gem_setup_path! "rubocop", "0.47.1"
+    Homebrew.install_gem_setup_path! "rubocop", HOMEBREW_RUBOCOP_VERSION
 
     args = %w[
       --force-exclusion
diff --git a/Library/Homebrew/config.rb b/Library/Homebrew/config.rb
index 38d7c8043..30b7bc6c9 100644
--- a/Library/Homebrew/config.rb
+++ b/Library/Homebrew/config.rb
@@ -2,6 +2,8 @@ unless ENV["HOMEBREW_BREW_FILE"]
   raise "HOMEBREW_BREW_FILE was not exported! Please call bin/brew directly!"
 end
 
+require "constants"
+
 # Path to `bin/brew` main executable in HOMEBREW_PREFIX
 HOMEBREW_BREW_FILE = Pathname.new(ENV["HOMEBREW_BREW_FILE"])
 
diff --git a/Library/Homebrew/constants.rb b/Library/Homebrew/constants.rb
new file mode 100644
index 000000000..660cad7a3
--- /dev/null
+++ b/Library/Homebrew/constants.rb
@@ -0,0 +1,3 @@
+# RuboCop version used for `brew style` and `brew cask style`
+HOMEBREW_RUBOCOP_VERSION = "0.47.1".freeze
+HOMEBREW_RUBOCOP_CASK_VERSION = "~> 0.11.0".freeze # has to be updated when RuboCop version changes
diff --git a/Library/Homebrew/dev-cmd/formula.rb b/Library/Homebrew/dev-cmd/formula.rb
new file mode 100644
index 000000000..71687dfa7
--- /dev/null
+++ b/Library/Homebrew/dev-cmd/formula.rb
@@ -0,0 +1,13 @@
+#:  * `formula` <formula>:
+#:    Display the path where <formula> is
+
+require "formula"
+
+module Homebrew
+  module_function
+
+  def formula
+    raise FormulaUnspecifiedError if ARGV.named.empty?
+    ARGV.resolved_formulae.each { |f| puts f.path }
+  end
+end
diff --git a/Library/Homebrew/test/formula_cmd_test.rb b/Library/Homebrew/test/formula_cmd_test.rb
new file mode 100644
index 000000000..abbe42d98
--- /dev/null
+++ b/Library/Homebrew/test/formula_cmd_test.rb
@@ -0,0 +1,8 @@
+require "testing_env"
+
+class IntegrationCommandTestFormula < IntegrationCommandTestCase
+  def test_formula
+    formula_file = setup_test_formula "testball"
+    assert_equal formula_file.to_s, cmd("formula", "testball")
+  end
+end
diff --git a/Library/Homebrew/test/support/lib/config.rb b/Library/Homebrew/test/support/lib/config.rb
index fb5c210fe..3a0a76722 100644
--- a/Library/Homebrew/test/support/lib/config.rb
+++ b/Library/Homebrew/test/support/lib/config.rb
@@ -2,6 +2,8 @@ unless ENV["HOMEBREW_BREW_FILE"]
   raise "HOMEBREW_BREW_FILE was not exported! Please call bin/brew directly!"
 end
 
+require "constants"
+
 require "tmpdir"
 require "pathname"
 
diff --git a/Library/Homebrew/test/x11_requirement_spec.rb b/Library/Homebrew/test/x11_requirement_spec.rb
new file mode 100644
index 000000000..f60c8bffe
--- /dev/null
+++ b/Library/Homebrew/test/x11_requirement_spec.rb
@@ -0,0 +1,36 @@
+require "requirements/x11_requirement"
+
+describe X11Requirement do
+  let(:default_name) { "x11" }
+
+  describe "#name" do
+    it "defaults to x11" do
+      expect(subject.name).to eq(default_name)
+    end
+  end
+
+  describe "#eql?" do
+    it "returns true if the names are equal" do
+      other = described_class.new(default_name)
+      expect(subject).to eql(other)
+    end
+
+    it "and returns false if the names differ" do
+      other = described_class.new("foo")
+      expect(subject).not_to eql(other)
+    end
+
+    it "returns false if the minimum version differs" do
+      other = described_class.new(default_name, ["2.5"])
+      expect(subject).not_to eql(other)
+    end
+  end
+
+  describe "#modify_build_environment" do
+    it "calls ENV#x11" do
+      allow(subject).to receive(:satisfied?).and_return(true)
+      expect(ENV).to receive(:x11)
+      subject.modify_build_environment
+    end
+  end
+end
diff --git a/Library/Homebrew/test/x11_requirement_test.rb b/Library/Homebrew/test/x11_requirement_test.rb
deleted file mode 100644
index b82a59e53..000000000
--- a/Library/Homebrew/test/x11_requirement_test.rb
+++ /dev/null
@@ -1,31 +0,0 @@
-require "testing_env"
-require "requirements/x11_requirement"
-
-class X11RequirementTests < Homebrew::TestCase
-  def test_eql_instances_are_eql
-    x = X11Requirement.new
-    y = X11Requirement.new
-    assert_eql x, y
-    assert_equal x.hash, y.hash
-  end
-
-  def test_not_eql_when_hashes_differ
-    x = X11Requirement.new("foo")
-    y = X11Requirement.new
-    refute_eql x, y
-    refute_equal x.hash, y.hash
-  end
-
-  def test_different_min_version
-    x = X11Requirement.new
-    y = X11Requirement.new("x11", %w[2.5])
-    refute_eql x, y
-  end
-
-  def test_x_env
-    x = X11Requirement.new
-    x.stubs(:satisfied?).returns(true)
-    ENV.expects(:x11)
-    x.modify_build_environment
-  end
-end
diff --git a/completions/zsh/_brew b/completions/zsh/_brew
index 9f7b8ebe5..04cf56f70 100644
--- a/completions/zsh/_brew
+++ b/completions/zsh/_brew
@@ -88,6 +88,7 @@ __brew_common_commands() {
     'doctor:audits your installation for common issues'
     'edit:edit a formula'
     'fetch:download formula resources to the cache'
+    'formula:the path for a formula'
     'gist-logs:generate a gist of the full build logs'
     'home:visit the homepage of a formula or the brew project'
     'info:information about a formula'
@@ -366,6 +367,11 @@ _brew_fetch() {
     '*:formula:__brew_formulae'
 }
 
+# brew formula formula:
+_brew_formula() {
+  __brew_formulae
+}
+
 # brew gist-logs [--new-issue|-n] formula
 _brew_gist_logs() {
   _arguments \
diff --git a/docs/brew.1.html b/docs/brew.1.html
index 6f2d1fb7b..e8b914281 100644
--- a/docs/brew.1.html
+++ b/docs/brew.1.html
@@ -540,6 +540,7 @@ you to explicitly set the name and version of the package you are creating.</p>
 the specified tap.</p></dd>
 <dt class="flush"><code>edit</code></dt><dd><p>Open all of Homebrew for editing.</p></dd>
 <dt><code>edit</code> <var>formula</var></dt><dd><p>Open <var>formula</var> in the editor.</p></dd>
+<dt><code>formula</code> <var>formula</var></dt><dd><p>Display the path where <var>formula</var> is</p></dd>
 <dt><code>linkage</code> [<code>--test</code>] [<code>--reverse</code>]  <var>formula-name</var></dt><dd><p>Checks the library links of an installed formula.</p>
 
 <p>Only works on installed formulae. An error is raised if it is run on
diff --git a/manpages/brew.1 b/manpages/brew.1
index 8a9625798..7591cf4ea 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -731,6 +731,10 @@ Open all of Homebrew for editing\.
 Open \fIformula\fR in the editor\.
 .
 .TP
+\fBformula\fR \fIformula\fR
+Display the path where \fIformula\fR is
+.
+.TP
 \fBlinkage\fR [\fB\-\-test\fR] [\fB\-\-reverse\fR] \fIformula\-name\fR
 Checks the library links of an installed formula\.
 .