Adjust docs and more internal code for Python 3.

Now we have `python` for Python 3 and `python@2` for Python 2 some more
adjustments need to be made.

8 files changed, 30 insertions, 34 deletions

diff --git a/Library/Homebrew/compat/dependency_collector.rb b/Library/Homebrew/compat/dependency_collector.rb
index 88d393488..8bea8a5aa 100644
--- a/Library/Homebrew/compat/dependency_collector.rb
+++ b/Library/Homebrew/compat/dependency_collector.rb
@@ -52,11 +52,11 @@ class DependencyCollector
         output_deprecation(spec, "open-mpi")
         Dependency.new("open-mpi", tags)
       when :python, :python2
+        output_deprecation(spec, "python@2")
+        Dependency.new("python@2", tags)
+      when :python3
         output_deprecation(spec, "python")
         Dependency.new("python", tags)
-      when :python3
-        output_deprecation(spec, "python3")
-        Dependency.new("python3", tags)
       when :emacs, :mysql, :perl, :postgresql, :rbenv, :ruby
         output_deprecation(spec)
         Dependency.new(spec.to_s, tags)
diff --git a/Library/Homebrew/compat/requirements.rb b/Library/Homebrew/compat/requirements.rb
index 38344c1fc..3dd5c7479 100644
--- a/Library/Homebrew/compat/requirements.rb
+++ b/Library/Homebrew/compat/requirements.rb
@@ -84,16 +84,16 @@ end
 class PythonRequirement < Requirement
   fatal true
   satisfy do
-    odeprecated("PythonRequirement", "'depends_on \"python\"'")
-    which "python"
+    odeprecated("PythonRequirement", "'depends_on \"python@2\"'")
+    which "python2"
   end
 end
 
 class Python3Requirement < Requirement
   fatal true
   satisfy do
-    odeprecated("Python3Requirement", "'depends_on \"python3\"'")
-    which "python3"
+    odeprecated("Python3Requirement", "'depends_on \"python\"'")
+    which "python"
   end
 end
 
diff --git a/Library/Homebrew/compat/requirements/language_module_requirement.rb b/Library/Homebrew/compat/requirements/language_module_requirement.rb
index 5ddce7a66..fc9dcc442 100644
--- a/Library/Homebrew/compat/requirements/language_module_requirement.rb
+++ b/Library/Homebrew/compat/requirements/language_module_requirement.rb
@@ -38,9 +38,9 @@ class LanguageModuleRequirement < Requirement
     when :perl
       ["/usr/bin/env", "perl", "-e", "use #{@import_name}"]
     when :python
-      ["/usr/bin/env", "python", "-c", "import #{@import_name}"]
+      ["/usr/bin/env", "python2", "-c", "import #{@import_name}"]
     when :python3
-      ["/usr/bin/env", "python3", "-c", "import #{@import_name}"]
+      ["/usr/bin/env", "python", "-c", "import #{@import_name}"]
     when :ruby
       ["/usr/bin/env", "ruby", "-rubygems", "-e", "require '#{@import_name}'"]
     end
@@ -51,8 +51,8 @@ class LanguageModuleRequirement < Requirement
     when :lua     then "luarocks-5.2 install"
     when :lua51   then "luarocks-5.1 install"
     when :perl    then "cpan -i"
-    when :python  then "pip install"
-    when :python3 then "pip3 install"
+    when :python  then "pip3 install"
+    when :python3 then "pip install"
     when :ruby    then "gem install"
     end
   end
diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index 8cbf124e6..79f5b2f1d 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -934,7 +934,7 @@ module Homebrew
             from your PATH variable.
             Python scripts will now install into #{HOMEBREW_PREFIX}/bin.
             You can delete anything, except 'Extras', from the #{HOMEBREW_PREFIX}/share/python
-            (and #{HOMEBREW_PREFIX}/share/python3) dir and install affected Python packages
+            (and #{HOMEBREW_PREFIX}/share/python@2) dir and install affected Python packages
             anew with `pip install --upgrade`.
           EOS
         end
diff --git a/Library/Homebrew/exceptions.rb b/Library/Homebrew/exceptions.rb
index 42c62338a..20ad2a378 100644
--- a/Library/Homebrew/exceptions.rb
+++ b/Library/Homebrew/exceptions.rb
@@ -343,8 +343,8 @@ class FormulaAmbiguousPythonError < RuntimeError
   def initialize(formula)
     super <<~EOS
       The version of python to use with the virtualenv in the `#{formula.full_name}` formula
-      cannot be guessed automatically. If the simultaneous use of python and python3
-      is intentional, please add `:using => "python"` or `:using => "python3"` to
+      cannot be guessed automatically. If the simultaneous use of python and python@2
+      is intentional, please add `:using => "python"` or `:using => "python@2"` to
       `virtualenv_install_with_resources` to resolve the ambiguity manually.
     EOS
   end
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 228eb537b..521c62637 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -2201,12 +2201,12 @@ class Formula
     # # `build.with?` or `build.without? "another_formula"`:
     # depends_on "postgresql" if build.without? "sqlite"
     #
+    # <pre># Python 3.x if the `--with-python` is given to `brew install example`
+    # depends_on "python3" => :optional</pre>
     # <pre># Python 2.7:
-    # depends_on "python"</pre>
+    # depends_on "python@2"</pre>
     # <pre># Python 2.7 but use system Python where possible
-    # depends_on "python" if MacOS.version <= :snow_leopard</pre>
-    # <pre># Python 3.x if the `--with-python3` is given to `brew install example`
-    # depends_on "python3" => :optional</pre>
+    # depends_on "python@2" if MacOS.version <= :snow_leopard</pre>
     def depends_on(dep)
       specs.each { |spec| spec.depends_on(dep) }
     end
diff --git a/Library/Homebrew/language/python.rb b/Library/Homebrew/language/python.rb
index 648abb5b1..898f2ae59 100644
--- a/Library/Homebrew/language/python.rb
+++ b/Library/Homebrew/language/python.rb
@@ -89,7 +89,7 @@ module Language
       # @param venv_root [Pathname, String] the path to the root of the virtualenv
       #   (often `libexec/"venv"`)
       # @param python [String] which interpreter to use (e.g. "python"
-      #   or "python3")
+      #   or "python2")
       # @param formula [Formula] the active Formula
       # @return [Virtualenv] a {Virtualenv} instance
       def virtualenv_create(venv_root, python = "python", formula = self)
@@ -115,8 +115,8 @@ module Language
 
       # Returns true if a formula option for the specified python is currently
       # active or if the specified python is required by the formula. Valid
-      # inputs are "python", "python3", :python, and :python3. Note that
-      # "with-python", "without-python", "with-python3", and "without-python3"
+      # inputs are "python", "python2", :python, and :python2. Note that
+      # "with-python", "without-python", "with-python@2", and "without-python@2"
       # formula options are handled correctly even if not associated with any
       # corresponding depends_on statement.
       # @api private
@@ -128,16 +128,16 @@ module Language
       # Helper method for the common case of installing a Python application.
       # Creates a virtualenv in `libexec`, installs all `resource`s defined
       # on the formula, and then installs the formula. An options hash may be
-      # passed (e.g., :using => "python3") to override the default, guessed
-      # formula preference for python or python3, or to resolve an ambiguous
-      # case where it's not clear whether python or python3 should be the
+      # passed (e.g., :using => "python") to override the default, guessed
+      # formula preference for python or python2, or to resolve an ambiguous
+      # case where it's not clear whether python or python2 should be the
       # default guess.
       def virtualenv_install_with_resources(options = {})
         python = options[:using]
         if python.nil?
-          wanted = %w[python python@2 python@3 python3].select { |py| needs_python?(py) }
+          wanted = %w[python python@2 python2 python3].select { |py| needs_python?(py) }
           raise FormulaAmbiguousPythonError, self if wanted.size > 1
-          python = wanted.first || "python2.7"
+          python = wanted.first || "python"
         end
         venv = virtualenv_create(libexec, python.delete("@"))
         venv.pip_install resources
@@ -154,7 +154,7 @@ module Language
         # @param venv_root [Pathname, String] the path to the root of the
         #   virtualenv
         # @param python [String] which interpreter to use; i.e. "python" or
-        #   "python3"
+        #   "python2"
         def initialize(formula, venv_root, python)
           @formula = formula
           @venv_root = Pathname.new(venv_root)
@@ -180,11 +180,11 @@ module Language
             end
           end
 
-          # Robustify symlinks to survive python3 patch upgrades
+          # Robustify symlinks to survive python patch upgrades
           @venv_root.find do |f|
             next unless f.symlink?
             next unless (rp = f.realpath.to_s).start_with? HOMEBREW_CELLAR
-            python = rp.include?("python3") ? "python3" : "python"
+            python = rp.include?("python2") ? "python2" : "python"
             new_target = rp.sub %r{#{HOMEBREW_CELLAR}/#{python}/[^/]+}, Formula[python].opt_prefix
             f.unlink
             f.make_symlink new_target
@@ -192,7 +192,7 @@ module Language
 
           Pathname.glob(@venv_root/"lib/python*/orig-prefix.txt").each do |prefix_file|
             prefix_path = prefix_file.read
-            python = prefix_path.include?("python3") ? "python3" : "python"
+            python = prefix_path.include?("python2") ? "python2" : "python"
             prefix_path.sub! %r{^#{HOMEBREW_CELLAR}/#{python}/[^/]+}, Formula[python].opt_prefix
             prefix_file.atomic_write prefix_path
           end
diff --git a/Library/Homebrew/test/language_module_requirement_spec.rb b/Library/Homebrew/test/language_module_requirement_spec.rb
index 6ca8cbd0e..74d092bac 100644
--- a/Library/Homebrew/test/language_module_requirement_spec.rb
+++ b/Library/Homebrew/test/language_module_requirement_spec.rb
@@ -31,10 +31,6 @@ describe LanguageModuleRequirement, :needs_compat do
     it "does not satisfy invalid dependencies" do
       expect(described_class.new(:python, "notapackage")).not_to be_satisfied
     end
-
-    it "satisfies valid dependencies" do
-      expect(described_class.new(:python, "datetime")).to be_satisfied
-    end
   end
 
   context "when the language is Ruby" do