bump-cask-pr: respect depends_on arch

This reworks the `SimulateSystem` args in the `bump-cask-pr`
`replace_version_and_checksum` method to respect `depends_on arch`
values in casks. That is to say, we shouldn't simulate Intel for a
cask using `depends_on arch: :arm64` and we shouldn't simulate ARM if
the cask uses `depends_on arch: :x86_64`.

In the process, this refactors how we collect/combine OS/arch values.
To make this approach work predictably, I removed the logic that
omits OS values matching the host OS (as `SimulateSystem` already
handles this). The `[{ os:, arch: }]` hash format only made sense when
we were omitting values, so this returns to the previous
`[[os, arch]]` array format (to align with the
`OnSystem::ALL_OS_ARCH_COMBINATIONS` array format).

Author: samford

Library/Homebrew/dev-cmd/bump-cask-pr.rb

@@ -194,29 +194,33 @@ def replace_version_and_checksum(cask, new_hash, new_version, replacement_pairs)
         host_is_macos = MacOSVersion::SYMBOLS.include?(host_os)
         newest_macos = MacOSVersion::SYMBOLS.keys.first
 
+        depends_on_archs = cask.depends_on.arch&.filter_map { |arch| arch[:type] }&.uniq
+
         # NOTE: We substitute the newest macOS (e.g. `:sequoia`) in place of
         # `:macos` values (when used), as a generic `:macos` value won't apply
-        # to on_system blocks referencing macOS versions. We also omit the OS
-        # when the value aligns with the host.
-        system_options = if cask.on_system_blocks_exist?
-          OnSystem::BASE_OS_OPTIONS.each_with_object([]) do |os, array|
-            OnSystem::ARCH_OPTIONS.each do |arch|
-              system_hash = { arch: }
-              system_hash[:os] = os if host_is_macos && os != :macos
-              system_hash[:os] = newest_macos if !host_is_macos && os == :macos
-              array << system_hash
+        # to on_system blocks referencing macOS versions.
+        os_values = []
+        arch_values = depends_on_archs.presence || []
+        if cask.on_system_blocks_exist?
+          OnSystem::BASE_OS_OPTIONS.each do |os|
+            os_values << if os == :macos
+              (host_is_macos ? host_os : newest_macos)
+            else
+              os
             end
-          end.uniq
+          end
+
+          arch_values = OnSystem::ARCH_OPTIONS if arch_values.empty?
         else
-          # Architecture is only relevant if on_system blocks are present. When
-          # not present, we default to ARM for consistency.
-          system_hash = { arch: :arm }
-          system_hash[:os] = newest_macos unless host_is_macos
-          [system_hash]
+          # Architecture is only relevant if on_system blocks are present or
+          # the cask uses `depends_on arch`, otherwise we default to ARM for
+          # consistency.
+          os_values << (host_is_macos ? host_os : newest_macos)
+          arch_values << :arm if arch_values.empty?
         end
 
-        system_options.each do |system_args|
-          SimulateSystem.with(**system_args) do
+        os_values.product(arch_values).each do |os, arch|
+          SimulateSystem.with(os:, arch:) do
             # Handle the cask being invalid for specific os/arch combinations
             old_cask = begin
               Cask::CaskLoader.load(cask.sourcefile_path)
@@ -228,7 +232,7 @@ def replace_version_and_checksum(cask, new_hash, new_version, replacement_pairs)
             old_version = old_cask.version
             next unless old_version
 
-            bump_version = new_version.send(system_args[:arch]) || new_version.general
+            bump_version = new_version.send(arch) || new_version.general
 
             old_version_regex = old_version.latest? ? ":latest" : %Q(["']#{Regexp.escape(old_version.to_s)}["'])
             replacement_pairs << [/version\s+#{old_version_regex}/m,