cask/config: new method for cask.config.explicit as string

Library/Homebrew/cask/config.rb

@@ -127,7 +127,7 @@ module Cask
           .map { |arg| T.cast(arg.split("=", 2), [String, String]) }
           .map do |(flag, value)|
             key = flag.sub(/^--/, "")
-
+            # converts --language flag to :languages config key
             if key == "language"
               key = "languages"
               value = value.split(",")
@@ -182,6 +182,18 @@ module Cask
       self.class.new(explicit: other.explicit.merge(explicit))
     end
 
+    sig { returns(String) }
+    def explicit_s
+      explicit.map do |key, value|
+        # inverse of #env - converts :languages config key back to --language flag
+        if key == :languages
+          key = "language"
+          value = languages.join(",")
+        end
+        "#{key}: \"#{value.to_s.sub(/^#{ENV['HOME']}/, "~")}\""
+      end.join(", ")
+    end
+
     sig { params(options: T.untyped).returns(String) }
     def to_json(**options)
       {

Library/Homebrew/test/cask/config_spec.rb

@@ -60,11 +60,22 @@ describe Cask::Config, :cask do
   end
 
   describe "#explicit" do
-    let(:config) { described_class.new(explicit: { appdir: "/explicit/path/to/apps" }) }
+    let(:config) {
+      described_class.new(explicit: { appdir:    "/explicit/path/to/apps",
+                                      languages: ["zh-TW", "en"] })
+    }
 
     it "returns directories explicitly given as arguments" do
       expect(config.explicit[:appdir]).to eq(Pathname("/explicit/path/to/apps"))
     end
+
+    it "returns array of preferred languages" do
+      expect(config.explicit[:languages]).to eq(["zh-TW", "en"])
+    end
+
+    it "returns string of explicit config keys and values" do
+      expect(config.explicit_s).to eq('appdir: "/explicit/path/to/apps", language: "zh-TW,en"')
+    end
   end
 
   context "when installing a cask and then adding a global default dir" do