cask/audit: support on_os blocks in audit_min_os

Library/Homebrew/cask/audit.rb

@@ -606,21 +606,30 @@
       debug_messages = []
       debug_messages << "Plist #{plist_min_os}" if plist_min_os
       debug_messages << "Sparkle #{sparkle_min_os}" if sparkle_min_os
-      odebug "Minimum OS version: #{debug_messages.join(" | ")}" unless debug_messages.empty?
+      odebug "Detected minimum OS version: #{debug_messages.join(" | ")}" unless debug_messages.empty?
       min_os = [plist_min_os, sparkle_min_os].compact.max
 
       return if min_os.nil? || min_os <= HOMEBREW_MACOS_OLDEST_ALLOWED
 
-      cask_min_os = cask.depends_on.macos&.version
-      return if cask_min_os == min_os
-
-      min_os_symbol = if cask_min_os.present?
-        cask_min_os.to_sym.inspect
+      cask_min_os = if cask.on_system_blocks_exist?
+        cask.on_system_block_min_os
+      else
+        cask.depends_on.macos&.minimum_version
+      end
+      odebug "Declared minimum OS version: #{cask_min_os&.to_sym}"
+      return if cask_min_os&.to_sym == min_os.to_sym
+
+      min_os_definition = if cask_min_os.present?
+        if cask.on_system_blocks_exist?
+          "a block with a minimum OS version of #{cask.on_system_block_min_os.inspect}"
+        else
+          cask_min_os.to_sym.inspect
+        end
       else
         "no minimum OS version"
       end
       add_error "Upstream defined #{min_os.to_sym.inspect} as the minimum OS version " \
-                "and the cask defined #{min_os_symbol}",
+                "and the cask declared #{min_os_definition}",
                 strict_only: true
     end
 

Library/Homebrew/cask/dsl.rb

@@ -95,6 +95,7 @@ class DSL
       :livecheck,
       :livecheckable?,
       :on_system_blocks_exist?,
+      :on_system_block_min_os,
       :depends_on_set_in_block?,
       *ORDINARY_ARTIFACT_CLASSES.map(&:dsl_key),
       *ACTIVATABLE_ARTIFACT_CLASSES.map(&:dsl_key),
@@ -104,7 +105,8 @@ class DSL
     extend Attrable
     include OnSystem::MacOSOnly
 
-    attr_reader :cask, :token, :deprecation_date, :deprecation_reason, :disable_date, :disable_reason
+    attr_reader :cask, :token, :deprecation_date, :deprecation_reason, :disable_date, :disable_reason,
+                :on_system_block_min_os
 
     attr_predicate :deprecated?, :disabled?, :livecheckable?, :on_system_blocks_exist?, :depends_on_set_in_block?
 

Library/Homebrew/extend/on_system.rb

@@ -130,6 +130,11 @@ def self.setup_macos_methods(base)
         os_condition = OnSystem.condition_from_method_name T.must(__method__)
         return unless OnSystem.os_condition_met? os_condition, or_condition
 
+        @on_system_block_min_os = if or_condition == :or_older
+          MacOSVersion.new(HOMEBREW_MACOS_OLDEST_ALLOWED).to_sym
+        else
+          os_condition
+        end
         @called_in_on_system_block = true
         result = block.call
         @called_in_on_system_block = false

Library/Homebrew/requirements/macos_requirement.rb

@@ -61,6 +61,13 @@ def version_specified?
     false
   end
 
+  def minimum_version
+    return MacOSVersion.new(HOMEBREW_MACOS_OLDEST_ALLOWED) if @comparator == "<=" || !version_specified?
+    return @version.min if @version.respond_to?(:to_ary)
+
+    @version
+  end
+
   def allows?(other)
     return true unless version_specified?
 

Library/Homebrew/test/requirements/macos_requirement_spec.rb

@@ -5,6 +5,7 @@
 RSpec.describe MacOSRequirement do
   subject(:requirement) { described_class.new }
 
+  let(:macos_oldest_allowed) { MacOSVersion.new(HOMEBREW_MACOS_OLDEST_ALLOWED) }
   let(:big_sur_major) { MacOSVersion.new("11.0") }
 
   describe "#satisfied?" do
@@ -23,11 +24,26 @@
     end
   end
 
+  specify "#minimum_version" do
+    no_requirement = described_class.new
+    max_requirement = described_class.new([:big_sur], comparator: "<=")
+    min_requirement = described_class.new([:big_sur], comparator: ">=")
+    exact_requirement = described_class.new([:big_sur], comparator: "==")
+    range_requirement = described_class.new([[:monterey, :big_sur]], comparator: "==")
+    expect(no_requirement.minimum_version).to eq macos_oldest_allowed
+    expect(max_requirement.minimum_version).to eq macos_oldest_allowed
+    expect(min_requirement.minimum_version).to eq big_sur_major
+    expect(exact_requirement.minimum_version).to eq big_sur_major
+    expect(range_requirement.minimum_version).to eq big_sur_major
+  end
+
   specify "#allows?" do
+    no_requirement = described_class.new
     max_requirement = described_class.new([:mojave], comparator: "<=")
     min_requirement = described_class.new([:catalina], comparator: ">=")
     exact_requirement = described_class.new([:big_sur], comparator: "==")
     range_requirement = described_class.new([[:monterey, :big_sur]], comparator: "==")
+    expect(no_requirement.allows?(big_sur_major)).to be true
     expect(max_requirement.allows?(big_sur_major)).to be false
     expect(min_requirement.allows?(big_sur_major)).to be true
     expect(exact_requirement.allows?(big_sur_major)).to be true