Add type check signatures

Author: abitrolly

Library/Homebrew/formula_creator.rb

@@ -7,8 +7,14 @@
 module Homebrew
   # Class for generating a formula from a template.
   class FormulaCreator
+    sig { returns(T.nilable(String)) }
     attr_accessor :name
-    attr_reader :head, :version
+
+    sig { returns(Version) }
+    attr_reader :version
+
+    sig { returns(T::Boolean) }
+    attr_reader :head
 
     sig {
       params(url: String, name: T.nilable(String), version: T.nilable(String), tap: T.nilable(String),
@@ -17,10 +23,10 @@ class FormulaCreator
     def initialize(url:, name: nil, version: nil, tap: nil, mode: nil, license: nil, fetch: false, head: false)
       @url = url
       @name = name.presence
-      @version = Version.new(version) if version.present?
-      @tap = Tap.fetch(tap.presence || "homebrew/core")
-      @mode = mode.presence
-      @license = license.presence
+      @version = T.let(Version.new(version), Version) if version.present?
+      @tap = T.let(Tap.fetch(tap.presence || "homebrew/core"), Tap)
+      @mode = T.let(mode.presence, T.nilable(Symbol))
+      @license = T.let(license.presence, T.nilable(String))
       @fetch = fetch
       @head = head
 
@@ -93,7 +99,7 @@ def write_formula!
             raise "Downloaded URL is not archive"
           end
 
-          @sha256 = filepath.sha256
+          @sha256 = T.let(filepath.sha256, T.nilable(String))
         end
 
         if @github