Implement conflicts_with :formula for casks

Library/Homebrew/cask/exceptions.rb

@@ -88,6 +88,34 @@
  end
  end
 
+ # Error when a cask conflicts with formulae.
+ #
+ # @api private
+ class CaskConflictWithFormulaError < AbstractCaskErrorWithToken
+ attr_reader :conflicting_formulae
+
+ def initialize(token, conflicting_formulae)
+ super(token)
+ @conflicting_formulae = conflicting_formulae
+ end
+
+ sig { returns(String) }
+ def to_s
+ message = []
+ message << "Cask '#{token}' conflicts with the following formulae that are installed:"
+ message.concat conflicting_formulae.map(&:conflict_message) << ""
+ message << <<~EOS
+ Please `brew unlink #{conflicting_formulae.map(&:name) * " "}` before continuing.
+
+ Unlinking removes a formula's symlinks from #{HOMEBREW_PREFIX}. You can
+ link the formula again after the install finishes. You can --force this
+ install, but the build may fail or cause obscure side effects in the
+ resulting software.
+ EOS
+ message.join("\n")
+ end
+ end
+
  # Error when a cask is not available.
  #
  # @api private

Library/Homebrew/cask/installer.rb

@@ -2,6 +2,7 @@
 # frozen_string_literal: true
 
 require "formula_installer"
+require "formula_conflict"
 require "unpack_strategy"
 require "utils/topological_hash"
 
@@ -138,6 +139,7 @@
  end
 
  def check_conflicts
+ return if force?
  return unless @cask.conflicts_with
 
  @cask.conflicts_with[:cask].each do |conflicting_cask|
@@ -151,6 +153,12 @@
  rescue CaskUnavailableError
  next # Ignore conflicting Casks that do not exist.
  end
+
+ formula_conflicts = @cask.conflicts_with[:formula].map do |conflicting_formula|
+ FormulaConflict.new(conflicting_formula, nil)
+ end
+ formula_conflicts.select! { |c| c.conflicts?(@cask) }
+ raise CaskConflictWithFormulaError.new(@cask, formula_conflicts) unless formula_conflicts.empty?
  end
 
  def uninstall_existing_cask

Library/Homebrew/exceptions.rb

@@ -420,18 +420,11 @@ def initialize(formula, conflicts)
  super message
  end
 
- def conflict_message(conflict)
- message = []
- message << " #{conflict.name}"
- message << ": because #{conflict.reason}" if conflict.reason
- message.join
- end
-
  sig { returns(String) }
  def message
  message = []
  message << "Cannot install #{formula.full_name} because conflicting formulae are installed."
- message.concat conflicts.map { |c| conflict_message(c) } << ""
+ message.concat conflicts.map(&:conflict_message) << ""
  message << <<~EOS
  Please `brew unlink #{conflicts.map(&:name) * " "}` before continuing.
 

Library/Homebrew/formula.rb

@@ -4,6 +4,7 @@
 require "cache_store"
 require "did_you_mean"
 require "formula_support"
+require "formula_conflict"
 require "lock_file"
 require "formula_pin"
 require "hardware"

Library/Homebrew/formula_conflict.rb

@@ -0,0 +1,41 @@
+# typed: true
+# frozen_string_literal: true
+
+# Used to track formulae that cannot be installed at the same time.
+FormulaConflict = Struct.new(:name, :reason) do
+ def conflict_message
+ message = []
+ message << " #{name}"
+ message << ": because #{reason}" if reason
+ message.join
+ end
+
+ def conflicts?(formula_or_cask)
+ f = Formulary.factory(name)
+ rescue TapFormulaUnavailableError
+ # If the formula name is a fully-qualified name let's silently
+ # ignore it as we don't care about things used in taps that aren't
+ # currently tapped.
+ false
+ rescue FormulaUnavailableError => e
+ # If the formula name doesn't exist any more then complain but don't
+ # stop installation from continuing.
+ official_tap, filename = if formula_or_cask.is_a?(Formula)
+ ["homebrew-core", formula_or_cask.path.basename]
+ else
+ ["homebrew-cask", formula_or_cask.sourcefile_path.basename]
+ end
+ opoo <<~EOS
+ #{formula_or_cask}: #{e.message}
+ 'conflicts_with "#{name}"' should be removed from #{filename}.
+ EOS
+
+ raise if Homebrew::EnvConfig.developer?
+
+ $stderr.puts "Please report this issue to the #{formula_or_cask.tap} tap " \
+ "(not Homebrew/brew or Homebrew/#{official_tap})!"
+ false
+ else
+ f.linked_keg.exist? && f.opt_prefix.exist?
+ end
+end

Library/Homebrew/formula_installer.rb

@@ -483,29 +483,7 @@ def install
  def check_conflicts
  return if force?
 
- conflicts = formula.conflicts.select do |c|
- f = Formulary.factory(c.name)
- rescue TapFormulaUnavailableError
- # If the formula name is a fully-qualified name let's silently
- # ignore it as we don't care about things used in taps that aren't
- # currently tapped.
- false
- rescue FormulaUnavailableError => e
- # If the formula name doesn't exist any more then complain but don't
- # stop installation from continuing.
- opoo <<~EOS
- #{formula}: #{e.message}
- 'conflicts_with "#{c.name}"' should be removed from #{formula.path.basename}.
- EOS
-
- raise if Homebrew::EnvConfig.developer?
-
- $stderr.puts "Please report this issue to the #{formula.tap} tap (not Homebrew/brew or Homebrew/homebrew-core)!"
- false
- else
- f.linked_keg.exist? && f.opt_prefix.exist?
- end
-
+ conflicts = formula.conflicts.select { |c| c.conflicts?(formula) }
  raise FormulaConflictError.new(formula, conflicts) unless conflicts.empty?
  end
 

Library/Homebrew/formula_support.rb

@@ -1,9 +1,6 @@
 # typed: true
 # frozen_string_literal: true
 
-# Used to track formulae that cannot be installed at the same time.
-FormulaConflict = Struct.new(:name, :reason)
-
 # Used to annotate formulae that duplicate macOS-provided software
 # or cause conflicts when linked in.
 class KegOnlyReason

Library/Homebrew/test/exceptions_spec.rb

@@ -166,7 +166,10 @@ class Baz < Formula; end
  subject { described_class.new(formula, [conflict]) }
 
  let(:formula) { instance_double(Formula, full_name: "foo/qux") }
- let(:conflict) { instance_double(FormulaConflict, name: "bar", reason: "I decided to") }
+ let(:conflict) do
+ instance_double(FormulaConflict, name: "bar", reason: "I decided to", conflicts?: true,
+ conflict_message: " bar: because I decided to")
+ end
 
  its(:to_s) { is_expected.to match(/Please `brew unlink bar` before continuing\./) }
  end

docs/Cask-Cookbook.md

@@ -154,7 +154,7 @@ Each cask must declare one or more *artifacts* (i.e. something to install).
 | name | multiple occurrences allowed? | value |
 | ------------------------------------------ | :---------------------------: | ----- |
 | [`uninstall`](#stanza-uninstall) | yes | Procedures to uninstall a cask. Optional unless the `pkg` stanza is used. |
-| [`conflicts_with`](#stanza-conflicts_with) | yes | List of conflicts with this cask (*not yet functional*). |
+| [`conflicts_with`](#stanza-conflicts_with) | yes | List of conflicts with this cask. |
 | [`caveats`](#stanza-caveats) | yes | String or Ruby block providing the user with cask-specific information at install time. |
 | [`deprecate!`](#stanza-deprecate--disable) | no | Date as a String in `YYYY-MM-DD` format and a String or Symbol providing a reason. |
 | [`disable!`](#stanza-deprecate--disable) | no | Date as a String in `YYYY-MM-DD` format and a String or Symbol providing a reason. |
@@ -351,8 +351,6 @@ conflicts_with cask: "macfuse-dev"
 
 #### `conflicts_with` *formula*
 
-**Note:** `conflicts_with formula:` is a stub and is not yet functional.
-
 The value should be another formula name.
 
 Example: [MacVim](https://github.com/Homebrew/homebrew-cask/blob/aa461148bbb5119af26b82cccf5003e2b4e50d95/Casks/m/macvim.rb#L16), which conflicts with the `macvim` formula.