SimulateSystem improvements

Library/Homebrew/extend/on_system.rb

@@ -15,8 +15,7 @@ module OnSystem
   def arch_condition_met?(arch)
     raise ArgumentError, "Invalid arch condition: #{arch.inspect}" if ARCH_OPTIONS.exclude?(arch)
 
-    current_arch = Homebrew::SimulateSystem.arch || Hardware::CPU.type
-    arch == current_arch
+    arch == Homebrew::SimulateSystem.current_arch
   end
 
   sig { params(os_name: Symbol, or_condition: T.nilable(Symbol)).returns(T::Boolean) }
@@ -26,25 +25,18 @@ def os_condition_met?(os_name, or_condition = nil)
       return true if [:macos, *MacOSVersions::SYMBOLS.keys].include?(os_name)
     end
 
-    if BASE_OS_OPTIONS.include?(os_name)
-      if Homebrew::SimulateSystem.none?
-        return OS.linux? if os_name == :linux
-        return OS.mac? if os_name == :macos
-      end
-
-      return Homebrew::SimulateSystem.send("#{os_name}?")
-    end
+    return Homebrew::SimulateSystem.send("treat_as_#{os_name}?") if BASE_OS_OPTIONS.include?(os_name)
 
     raise ArgumentError, "Invalid OS condition: #{os_name.inspect}" unless MacOSVersions::SYMBOLS.key?(os_name)
 
     if or_condition.present? && [:or_newer, :or_older].exclude?(or_condition)
       raise ArgumentError, "Invalid OS `or_*` condition: #{or_condition.inspect}"
     end
 
-    return false if Homebrew::SimulateSystem.linux? || (Homebrew::SimulateSystem.none? && OS.linux?)
+    return false if Homebrew::SimulateSystem.treat_as_linux?
 
     base_os = MacOS::Version.from_symbol(os_name)
-    current_os = MacOS::Version.from_symbol(Homebrew::SimulateSystem.os || MacOS.version.to_sym)
+    current_os = MacOS::Version.from_symbol(Homebrew::SimulateSystem.current_os)
 
     return current_os >= base_os if or_condition == :or_newer
     return current_os <= base_os if or_condition == :or_older

Library/Homebrew/extend/os/linux/formula.rb

@@ -23,17 +23,4 @@ def rpath
 
   sig { params(targets: T.nilable(T.any(Pathname, String))).void }
   def deuniversalize_machos(*targets); end
-
-  class << self
-    undef ignore_missing_libraries
-
-    def ignore_missing_libraries(*libs)
-      libraries = libs.flatten
-      if libraries.any? { |x| !x.is_a?(String) && !x.is_a?(Regexp) }
-        raise FormulaSpecificationError, "#{__method__} can handle Strings and Regular Expressions only"
-      end
-
-      allowed_missing_libraries.merge(libraries)
-    end
-  end
 end

Library/Homebrew/extend/os/software_spec.rb

@@ -1,9 +1,4 @@
 # typed: strict
 # frozen_string_literal: true
 
-# This logic will need to be more nuanced if this file includes more than `uses_from_macos`.
-if OS.mac? || Homebrew::EnvConfig.simulate_macos_on_linux?
-  require "extend/os/mac/software_spec"
-elsif OS.linux?
-  require "extend/os/linux/software_spec"
-end
+require "extend/os/linux/software_spec" if OS.linux?

Library/Homebrew/formula.rb

@@ -3214,10 +3214,17 @@ def link_overwrite_paths
     end
 
     # Permit links to certain libraries that don't exist. Available on Linux only.
-    def ignore_missing_libraries(*)
-      return if Homebrew::SimulateSystem.linux?
+    def ignore_missing_libraries(*libs)
+      unless Homebrew::SimulateSystem.treat_as_linux?
+        raise FormulaSpecificationError, "#{__method__} is available on Linux only"
+      end
+
+      libraries = libs.flatten
+      if libraries.any? { |x| !x.is_a?(String) && !x.is_a?(Regexp) }
+        raise FormulaSpecificationError, "#{__method__} can handle Strings and Regular Expressions only"
+      end
 
-      raise FormulaSpecificationError, "#{__method__} is available on Linux only"
+      allowed_missing_libraries.merge(libraries)
     end
 
     # @private

Library/Homebrew/simulate_system.rb

@@ -32,19 +32,31 @@ def clear
       end
 
       sig { returns(T::Boolean) }
-      def none?
-        @os.nil? && @arch.nil?
-      end
+      def treat_as_macos?
+        return OS.mac? if @os.blank?
 
-      sig { returns(T::Boolean) }
-      def macos?
         [:macos, *MacOSVersions::SYMBOLS.keys].include?(@os)
       end
 
       sig { returns(T::Boolean) }
-      def linux?
+      def treat_as_linux?
+        return OS.linux? if @os.blank?
+
         @os == :linux
       end
+
+      sig { returns(Symbol) }
+      def current_arch
+        @arch || Hardware::CPU.type
+      end
+
+      sig { returns(Symbol) }
+      def current_os
+        return @os if @os.present?
+        return :linux if OS.linux?
+
+        MacOS.version.to_sym
+      end
     end
   end
 end

Library/Homebrew/software_spec.rb

@@ -162,12 +162,25 @@ def depends_on(spec)
     add_dep_option(dep) if dep
   end
 
-  def uses_from_macos(spec, _bounds = {})
-    spec = [spec.dup.shift].to_h if spec.is_a?(Hash)
+  def uses_from_macos(deps, bounds = {})
+    if deps.is_a?(Hash)
+      bounds = deps.dup
+      deps = [bounds.shift].to_h
+    end
+
+    @uses_from_macos_elements << deps
 
-    @uses_from_macos_elements << spec
+    # Linux simulating macOS. Assume oldest macOS version.
+    return if Homebrew::EnvConfig.simulate_macos_on_linux? && !bounds.key?(:since)
+
+    # macOS new enough for dependency to not be required.
+    if Homebrew::SimulateSystem.treat_as_macos?
+      current_os = MacOS::Version.from_symbol(Homebrew::SimulateSystem.current_os)
+      since_os = MacOS::Version.from_symbol(bounds[:since]) if bounds.key?(:since)
+      return if current_os >= since_os
+    end
 
-    depends_on(spec)
+    depends_on deps
   end
 
   def uses_from_macos_names

Library/Homebrew/test/formula_spec.rb

@@ -1845,4 +1845,52 @@ def install
       expect(f.test).to eq(2)
     end
   end
+
+  describe "#ignore_missing_libraries" do
+    after do
+      Homebrew::SimulateSystem.clear
+    end
+
+    it "adds library to allowed_missing_libraries on Linux", :needs_linux do
+      Homebrew::SimulateSystem.clear
+      f = formula do
+        url "foo-1.0"
+
+        ignore_missing_libraries "bar.so"
+      end
+      expect(f.class.allowed_missing_libraries.to_a).to eq(["bar.so"])
+    end
+
+    it "adds library to allowed_missing_libraries on macOS when simulating Linux", :needs_macos do
+      Homebrew::SimulateSystem.os = :linux
+      f = formula do
+        url "foo-1.0"
+
+        ignore_missing_libraries "bar.so"
+      end
+      expect(f.class.allowed_missing_libraries.to_a).to eq(["bar.so"])
+    end
+
+    it "raises an error on macOS", :needs_macos do
+      Homebrew::SimulateSystem.clear
+      expect {
+        formula do
+          url "foo-1.0"
+
+          ignore_missing_libraries "bar.so"
+        end
+      }.to raise_error("ignore_missing_libraries is available on Linux only")
+    end
+
+    it "raises an error on Linux when simulating macOS", :needs_linux do
+      Homebrew::SimulateSystem.os = :macos
+      expect {
+        formula do
+          url "foo-1.0"
+
+          ignore_missing_libraries "bar.so"
+        end
+      }.to raise_error("ignore_missing_libraries is available on Linux only")
+    end
+  end
 end