cask: tolerate asymmetric variations in to_hash_with_variations

When a cask uses on_system blocks that legitimately omit some arches
on a given OS (e.g. on_linux with only x86_64_linux sha256 plus
depends_on arch: :x86_64), `refresh` under `SimulateSystem.with_tag`
raises CaskInvalidError for the unsupported combos. Rescue these so
the variations iteration produces the supported subset instead of
aborting the entire call chain.

Fixes generate-cask-ci-matrix failures on cask PRs with intentional
arch asymmetry (e.g. devin-cli).

Author: p-linnane

Library/Homebrew/cask/cask.rb

@@ -592,16 +592,20 @@ def to_hash_with_variations
                     !dsl!.depends_on_set_in_block? &&
                     macos_requirements.any? { |requirement| !requirement.allows?(bottle_tag.to_macos_version) }
 
-            Homebrew::SimulateSystem.with_tag(bottle_tag) do
-              refresh
+            begin
+              Homebrew::SimulateSystem.with_tag(bottle_tag) do
+                refresh
 
-              to_h.each do |key, value|
-                next if HASH_KEYS_TO_SKIP.include? key
-                next if value.to_s == hash[key].to_s
+                to_h.each do |key, value|
+                  next if HASH_KEYS_TO_SKIP.include? key
+                  next if value.to_s == hash[key].to_s
 
-                variations[bottle_tag.to_sym] ||= {}
-                variations[bottle_tag.to_sym][key] = value
+                  variations[bottle_tag.to_sym] ||= {}
+                  variations[bottle_tag.to_sym][key] = value
+                end
               end
+            rescue CaskInvalidError, CaskUnreadableError
+              # Skip OS/arch combinations the cask intentionally doesn't define.
             end
           end
         ensure

Library/Homebrew/test/cask/cask_spec.rb

@@ -744,6 +744,14 @@ def write_auto_updates_cask(path, version:, artifacts:, token: "auto-updates-bun
       expect(JSON.pretty_generate(h["variations"])).to eq expected_sha256_variations_os.strip
     end
 
+    it "omits tags a cask intentionally doesn't define in on_system blocks" do
+      c = Cask::CaskLoader.load("on-linux-asymmetric")
+      h = c.to_hash_with_variations
+
+      expect(h["variations"]).to include(:x86_64_linux)
+      expect(h["variations"]).not_to include(:arm64_linux)
+    end
+
     # NOTE: The calls to `Cask.generating_hash!` and `Cask.generated_hash!`
     #       are not idempotent so they can only be used in one test.
     it "returns the correct hash placeholders" do

Library/Homebrew/test/support/fixtures/cask/Casks/on-linux-asymmetric.rb

@@ -0,0 +1,24 @@
+# typed: false
+
+cask "on-linux-asymmetric" do
+  arch arm: "arm", intel: "intel"
+  os macos: "darwin", linux: "linux"
+
+  version "1.2.3"
+
+  url "file://#{TEST_FIXTURE_DIR}/cask/caffeine-#{arch}-#{os}.zip"
+  homepage "https://brew.sh/"
+
+  on_macos do
+    sha256 arm:   "67cdb8a02803ef37fdbf7e0be205863172e41a561ca446cd84f0d7ab35a99d94",
+           intel: "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
+  end
+
+  on_linux do
+    sha256 x86_64_linux: "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
+
+    depends_on arch: :x86_64
+  end
+
+  app "Caffeine.app"
+end