Formulary: use variations hash when installing from API

Library/Homebrew/formulary.rb

@@ -136,6 +136,11 @@ module Formulary
     class_s = Formulary.class_s(name)
     json_formula = Homebrew::API::Formula.all_formulae[name]
 
+    bottle_tag = Utils::Bottles.tag.to_s
+    if json_formula.key?("variations") && json_formula["variations"].key?(bottle_tag)
+      json_formula = json_formula.merge(json_formula["variations"][bottle_tag])
+    end
+
     klass = Class.new(::Formula) do
       desc json_formula["desc"]
       homepage json_formula["homepage"]

Library/Homebrew/test/formulary_spec.rb

@@ -260,6 +260,16 @@ describe Formulary do
         }
       end
 
+      let(:variations_json) do
+        {
+          "variations" => {
+            Utils::Bottles.tag.to_s => {
+              "dependencies" => ["dep", "variations_dep"],
+            },
+          },
+        }
+      end
+
       before do
         allow(described_class).to receive(:loader_for).and_return(described_class::FormulaAPILoader.new(formula_name))
       end
@@ -303,6 +313,16 @@ describe Formulary do
           formula.install
         }.to raise_error("Cannot build from source from abstract formula.")
       end
+
+      it "returns a Formula with variations when given a name", :needs_macos do
+        allow(Homebrew::API::Formula).to receive(:all_formulae).and_return formula_json_contents(variations_json)
+        allow(Utils::Bottles).to receive(:tag).and_return(:arm64_monterey)
+
+        formula = described_class.factory(formula_name)
+        expect(formula).to be_kind_of(Formula)
+        expect(formula.deps.count).to eq 5
+        expect(formula.deps.map(&:name).include?("variations_dep")).to be true
+      end
     end
   end