17 files changed, 109 insertions, 48 deletions
diff --git a/.travis.yml b/.travis.yml
index 37417a10a..fef0f91ca 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,7 +3,7 @@ cache:
   directories:
     - $HOME/Library/Caches/Homebrew/style
     - $HOME/Library/Caches/Homebrew/tests
-    - $HOME/Library/Homebrew/vendor/bundle
+    - Library/Homebrew/vendor/bundle
 branches:
   only:
     - master
@@ -37,11 +37,6 @@ before_install:
       sudo rm -rf "$HOMEBREW_REPOSITORY";
       sudo ln -s "$PWD" "$HOMEBREW_REPOSITORY";
     fi
-  - if [ "$MACOS" ]; then
-      travis_retry git -C Library/Taps/homebrew/homebrew-core fetch --depth=1 origin;
-    else
-      travis_retry git clone --depth=1 https://github.com/Homebrew/homebrew-core Library/Taps/homebrew/homebrew-core;
-    fi
   - travis_retry git clone --depth=1 https://github.com/Homebrew/homebrew-test-bot Library/Taps/homebrew/homebrew-test-bot
 
 script:
diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index 77a60dfc7..590dde363 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -253,6 +253,14 @@ then
   then
     export HOMEBREW_DEV_CMD_RUN="1"
   fi
+
+  # Don't allow non-developers to customise Ruby warnings.
+  unset HOMEBREW_RUBY_WARNINGS
+fi
+
+if [[ -z "$HOMEBREW_RUBY_WARNINGS" ]]
+then
+  export HOMEBREW_RUBY_WARNINGS="-W0"
 fi
 
 if [[ -f "$HOMEBREW_LIBRARY/Homebrew/cmd/$HOMEBREW_COMMAND.sh" ]]
@@ -371,5 +379,5 @@ else
 
   # Unshift command back into argument list (unless argument list was empty).
   [[ "$HOMEBREW_ARG_COUNT" -gt 0 ]] && set -- "$HOMEBREW_COMMAND" "$@"
-  { update-preinstall; exec "$HOMEBREW_RUBY_PATH" -W0 "$HOMEBREW_LIBRARY/Homebrew/brew.rb" "$@"; }
+  { update-preinstall; exec "$HOMEBREW_RUBY_PATH" $HOMEBREW_RUBY_WARNINGS "$HOMEBREW_LIBRARY/Homebrew/brew.rb" "$@"; }
 fi
diff --git a/Library/Homebrew/cmd/irb.rb b/Library/Homebrew/dev-cmd/irb.rb
index 4cd3d4c9e..700cbe009 100644
--- a/Library/Homebrew/cmd/irb.rb
+++ b/Library/Homebrew/dev-cmd/irb.rb
@@ -1,11 +1,9 @@
-#:  * `irb` [`--examples`]:
+#:  * `irb` [`--examples`] [`--pry`]:
 #:    Enter the interactive Homebrew Ruby shell.
 #:
 #:    If `--examples` is passed, several examples will be shown.
-
-require "formula"
-require "keg"
-require "irb"
+#:    If `--pry` is passed or HOMEBREW_PRY is set, pry will be
+#:    used instead of irb.
 
 class Symbol
   def f(*args)
@@ -23,17 +21,33 @@ module Homebrew
   module_function
 
   def irb
-    $LOAD_PATH.unshift("#{HOMEBREW_LIBRARY_PATH}/cask/lib")
-    require "hbc"
-
     if ARGV.include? "--examples"
       puts "'v8'.f # => instance of the v8 formula"
       puts ":hub.f.installed?"
       puts ":lua.f.methods - 1.methods"
       puts ":mpd.f.recursive_dependencies.reject(&:installed?)"
+      return
+    end
+
+    if ARGV.pry?
+      Homebrew.install_gem_setup_path! "pry"
+      require "pry"
+      Pry.config.prompt_name = "brew"
+    else
+      require "irb"
+    end
+
+    require "formula"
+    require "keg"
+
+    $LOAD_PATH.unshift("#{HOMEBREW_LIBRARY_PATH}/cask/lib")
+    require "hbc"
+
+    ohai "Interactive Homebrew Shell"
+    puts "Example commands available with: brew irb --examples"
+    if ARGV.pry?
+      Pry.start
     else
-      ohai "Interactive Homebrew Shell"
-      puts "Example commands available with: brew irb --examples"
       IRB.start
     end
   end
diff --git a/Library/Homebrew/dev-cmd/linkage.rb b/Library/Homebrew/dev-cmd/linkage.rb
index 31e9bd103..c33c181a1 100644
--- a/Library/Homebrew/dev-cmd/linkage.rb
+++ b/Library/Homebrew/dev-cmd/linkage.rb
@@ -10,7 +10,7 @@
 #:    If `--reverse` is passed, print the dylib followed by the binaries
 #:    which link to it for each library the keg references.
 
-require "os/mac/linkage_checker"
+require "linkage_checker"
 
 module Homebrew
   module_function
diff --git a/Library/Homebrew/dev-cmd/ruby.rb b/Library/Homebrew/dev-cmd/ruby.rb
index 2df212301..c5696d6bb 100755
--- a/Library/Homebrew/dev-cmd/ruby.rb
+++ b/Library/Homebrew/dev-cmd/ruby.rb
@@ -8,6 +8,6 @@ module Homebrew
   module_function
 
   def ruby
-    exec ENV["HOMEBREW_RUBY_PATH"], "-I#{HOMEBREW_LIBRARY_PATH}", "-rglobal", "-rcmd/irb", *ARGV
+    exec ENV["HOMEBREW_RUBY_PATH"], "-I#{HOMEBREW_LIBRARY_PATH}", "-rglobal", "-rdev-cmd/irb", *ARGV
   end
 end
diff --git a/Library/Homebrew/dev-cmd/tap-new.rb b/Library/Homebrew/dev-cmd/tap-new.rb
index 38cdb1c2e..31299d2b0 100644
--- a/Library/Homebrew/dev-cmd/tap-new.rb
+++ b/Library/Homebrew/dev-cmd/tap-new.rb
@@ -50,8 +50,7 @@ module Homebrew
       osx_image: xcode9.2
       cache:
         directories:
-          - $HOME/.gem/ruby
-          - Library/Homebrew/vendor/bundle
+          - /usr/local/Homebrew/Library/Homebrew/vendor/bundle
       branches:
         only:
           - master
diff --git a/Library/Homebrew/extend/ARGV.rb b/Library/Homebrew/extend/ARGV.rb
index d9da014f0..2bc84620a 100644
--- a/Library/Homebrew/extend/ARGV.rb
+++ b/Library/Homebrew/extend/ARGV.rb
@@ -267,6 +267,10 @@ module HomebrewArgvExtension
     include? "--fetch-HEAD"
   end
 
+  def pry?
+    include?("--pry") || !ENV["HOMEBREW_PRY"].nil?
+  end
+
   # eg. `foo -ns -i --bar` has three switches, n, s and i
   def switch?(char)
     return false if char.length > 1
diff --git a/Library/Homebrew/extend/ENV.rb b/Library/Homebrew/extend/ENV.rb
index 374be49b9..002220764 100644
--- a/Library/Homebrew/extend/ENV.rb
+++ b/Library/Homebrew/extend/ENV.rb
@@ -28,9 +28,9 @@ module EnvActivation
   end
 
   def clear_sensitive_environment!
-    ENV.each_key do |key|
+    each_key do |key|
       next unless /(cookie|key|token|password)/i =~ key
-      ENV.delete key
+      delete key
     end
   end
 end
diff --git a/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb b/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb
index 901d8945f..0b1a1643e 100644
--- a/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb
+++ b/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb
@@ -1,4 +1,4 @@
-require "os/mac/linkage_checker"
+require "linkage_checker"
 
 module FormulaCellarChecks
   def check_shadowed_headers
diff --git a/Library/Homebrew/language/python.rb b/Library/Homebrew/language/python.rb
index 3908f4b8f..648abb5b1 100644
--- a/Library/Homebrew/language/python.rb
+++ b/Library/Homebrew/language/python.rb
@@ -15,10 +15,11 @@ module Language
 
     def self.each_python(build, &block)
       original_pythonpath = ENV["PYTHONPATH"]
-      ["python", "python3"].each do |python|
-        next if build.without? python
+      { "python@3" => "python3", "python@2" => "python2.7" }.each do |python_formula, python|
+        python_formula = Formulary.factory(python_formula)
+        next if build.without? python_formula.to_s
         version = major_minor_version python
-        ENV["PYTHONPATH"] = if Formulary.factory(python).installed?
+        ENV["PYTHONPATH"] = if python_formula.installed?
           nil
         else
           homebrew_site_packages(version)
diff --git a/Library/Homebrew/os/mac/linkage_checker.rb b/Library/Homebrew/linkage_checker.rb
index cf6c12f22..cf6c12f22 100644
--- a/Library/Homebrew/os/mac/linkage_checker.rb
+++ b/Library/Homebrew/linkage_checker.rb
diff --git a/Library/Homebrew/manpages/brew.1.md.erb b/Library/Homebrew/manpages/brew.1.md.erb
index 533e1d594..618e050f6 100644
--- a/Library/Homebrew/manpages/brew.1.md.erb
+++ b/Library/Homebrew/manpages/brew.1.md.erb
@@ -183,6 +183,10 @@ can take several different forms:
 
     *Note:* Homebrew doesn't require permissions for any of the scopes.
 
+  * `HOMEBREW_INSTALL_BADGE`:
+    Text printed before the installation summary of each successful build.
+    Defaults to the beer emoji.
+
   * `HOMEBREW_LOGS`:
     If set, Homebrew will use the given directory to store log files.
 
@@ -220,9 +224,8 @@ can take several different forms:
     If set, Homebrew will not use the GitHub API for e.g searches or
     fetching relevant issues on a failed install.
 
-  * `HOMEBREW_INSTALL_BADGE`:
-    Text printed before the installation summary of each successful build.
-    Defaults to the beer emoji.
+  * `HOMEBREW_PRY`:
+    If set, Homebrew will use `pry` for the `brew irb` command.
 
   * `HOMEBREW_SVN`:
     When exporting from Subversion, Homebrew will use `HOMEBREW_SVN` if set,
diff --git a/Library/Homebrew/migrator.rb b/Library/Homebrew/migrator.rb
index 8664d474b..3ccf2f23c 100644
--- a/Library/Homebrew/migrator.rb
+++ b/Library/Homebrew/migrator.rb
@@ -288,7 +288,8 @@ class Migrator
     new_keg.remove_linked_keg_record if new_keg.linked?
 
     begin
-      new_keg.link
+      mode = OpenStruct.new(overwrite: true)
+      new_keg.link(mode)
     rescue Keg::ConflictError => e
       onoe "Error while executing `brew link` step on #{newname}"
       puts e
diff --git a/Library/Homebrew/test/ENV_spec.rb b/Library/Homebrew/test/ENV_spec.rb
index 07f6cdb6b..8b39e52d7 100644
--- a/Library/Homebrew/test/ENV_spec.rb
+++ b/Library/Homebrew/test/ENV_spec.rb
@@ -141,6 +141,20 @@ shared_examples EnvActivation do
 
     expect(subject["MAKEFLAGS"]).to eq("-j4")
   end
+
+  describe "#clear_sensitive_environment!" do
+    it "removes sensitive environment variables" do
+      subject["SECRET_TOKEN"] = "password"
+      subject.clear_sensitive_environment!
+      expect(subject).not_to include("SECRET_TOKEN")
+    end
+
+    it "leaves non-sensitive environment variables alone" do
+      subject["FOO"] = "bar"
+      subject.clear_sensitive_environment!
+      expect(subject["FOO"]).to eq "bar"
+    end
+  end
 end
 
 describe Stdenv do
diff --git a/Library/Homebrew/test/dev-cmd/ruby_spec.rb b/Library/Homebrew/test/dev-cmd/ruby_spec.rb
new file mode 100644
index 000000000..e05bccc83
--- /dev/null
+++ b/Library/Homebrew/test/dev-cmd/ruby_spec.rb
@@ -0,0 +1,13 @@
+describe "brew ruby", :integration_test do
+  it "executes ruby code with Homebrew's libraries loaded" do
+    expect { brew "ruby", "-e", "exit 0" }
+      .to be_a_success
+      .and not_to_output.to_stdout
+      .and not_to_output.to_stderr
+
+    expect { brew "ruby", "-e", "exit 1" }
+      .to be_a_failure
+      .and not_to_output.to_stdout
+      .and not_to_output.to_stderr
+  end
+end
diff --git a/docs/Manpage.md b/docs/Manpage.md
index 6b6dc91ab..ff3346685 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -280,11 +280,6 @@ With `--verbose` or `-v`, many commands print extra debugging information. Note
     If `--git` (or `-g`) is passed, Homebrew will create a Git repository, useful for
     creating patches to the software.
 
-  * `irb` [`--examples`]:
-    Enter the interactive Homebrew Ruby shell.
-
-    If `--examples` is passed, several examples will be shown.
-
   * `leaves`:
     Show installed formulae that are not dependencies of another installed formula.
 
@@ -761,6 +756,13 @@ With `--verbose` or `-v`, many commands print extra debugging information. Note
   * `formula` `formula`:
     Display the path where `formula` is located.
 
+  * `irb` [`--examples`] [`--pry`]:
+    Enter the interactive Homebrew Ruby shell.
+
+    If `--examples` is passed, several examples will be shown.
+    If `--pry` is passed or HOMEBREW_PRY is set, pry will be
+    used instead of irb.
+
   * `linkage` [`--test`] [`--reverse`] `formula`:
     Checks the library links of an installed formula.
 
@@ -1029,6 +1031,10 @@ can take several different forms:
 
     *Note:* Homebrew doesn't require permissions for any of the scopes.
 
+  * `HOMEBREW_INSTALL_BADGE`:
+    Text printed before the installation summary of each successful build.
+    Defaults to the beer emoji.
+
   * `HOMEBREW_LOGS`:
     If set, Homebrew will use the given directory to store log files.
 
@@ -1066,9 +1072,8 @@ can take several different forms:
     If set, Homebrew will not use the GitHub API for e.g searches or
     fetching relevant issues on a failed install.
 
-  * `HOMEBREW_INSTALL_BADGE`:
-    Text printed before the installation summary of each successful build.
-    Defaults to the beer emoji.
+  * `HOMEBREW_PRY`:
+    If set, Homebrew will use `pry` for the `brew irb` command.
 
   * `HOMEBREW_SVN`:
     When exporting from Subversion, Homebrew will use `HOMEBREW_SVN` if set,
diff --git a/manpages/brew.1 b/manpages/brew.1
index 0f99f3af6..60cd7cc80 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -291,13 +291,6 @@ If \fB\-\-interactive\fR (or \fB\-i\fR) is passed, download and patch \fIformula
 If \fB\-\-git\fR (or \fB\-g\fR) is passed, Homebrew will create a Git repository, useful for creating patches to the software\.
 .
 .TP
-\fBirb\fR [\fB\-\-examples\fR]
-Enter the interactive Homebrew Ruby shell\.
-.
-.IP
-If \fB\-\-examples\fR is passed, several examples will be shown\.
-.
-.TP
 \fBleaves\fR
 Show installed formulae that are not dependencies of another installed formula\.
 .
@@ -781,6 +774,13 @@ Open \fIformula\fR in the editor\.
 Display the path where \fIformula\fR is located\.
 .
 .TP
+\fBirb\fR [\fB\-\-examples\fR] [\fB\-\-pry\fR]
+Enter the interactive Homebrew Ruby shell\.
+.
+.IP
+If \fB\-\-examples\fR is passed, several examples will be shown\. If \fB\-\-pry\fR is passed or HOMEBREW_PRY is set, pry will be used instead of irb\.
+.
+.TP
 \fBlinkage\fR [\fB\-\-test\fR] [\fB\-\-reverse\fR] \fIformula\fR
 Checks the library links of an installed formula\.
 .
@@ -1048,6 +1048,10 @@ A personal access token for the GitHub API, which you can create at \fIhttps://g
 \fINote:\fR Homebrew doesn\'t require permissions for any of the scopes\.
 .
 .TP
+\fBHOMEBREW_INSTALL_BADGE\fR
+Text printed before the installation summary of each successful build\. Defaults to the beer emoji\.
+.
+.TP
 \fBHOMEBREW_LOGS\fR
 If set, Homebrew will use the given directory to store log files\.
 .
@@ -1089,8 +1093,8 @@ While ensuring your downloads are fully secure, this is likely to cause from\-so
 If set, Homebrew will not use the GitHub API for e\.g searches or fetching relevant issues on a failed install\.
 .
 .TP
-\fBHOMEBREW_INSTALL_BADGE\fR
-Text printed before the installation summary of each successful build\. Defaults to the beer emoji\.
+\fBHOMEBREW_PRY\fR
+If set, Homebrew will use \fBpry\fR for the \fBbrew irb\fR command\.
 .
 .TP
 \fBHOMEBREW_SVN\fR