Enable strict typing in Formula

Library/Homebrew/caveats.rb

@@ -19,8 +19,8 @@ class Caveats
   sig { returns(String) }
   def caveats
     caveats = []
-    begin
     build = formula.build
+    begin
       formula.build = Tab.for_formula(formula)
       string = formula.caveats.to_s
       caveats << "#{string.chomp}\n" unless string.empty?

Library/Homebrew/cmd/info.rb

@@ -209,7 +209,8 @@ module Homebrew
             formulae.map(&:to_hash)
           end
         when :v2
-          formulae, casks = if all
+          formulae, casks = T.let(
+            if all
               [
                 Formula.all(eval_all: args.eval_all?).sort,
                 Cask::Cask.all(eval_all: args.eval_all?).sort_by(&:full_name),
@@ -217,8 +218,9 @@ module Homebrew
             elsif args.installed?
               [Formula.installed.sort, Cask::Caskroom.casks.sort_by(&:full_name)]
             else
-            args.named.to_formulae_to_casks
+              T.cast(args.named.to_formulae_to_casks, [T::Array[Formula], T::Array[Cask::Cask]])
-          end
+            end, [T::Array[Formula], T::Array[Cask::Cask]]
+          )
 
           if args.variations?
             {

Library/Homebrew/cmd/list.rb

@@ -123,7 +123,8 @@ module Homebrew
           raise UsageError, "Cannot use #{flags.join(", ")} with formula arguments." unless args.no_named?
 
           formulae = if args.t?
-            Formula.installed.sort_by { |formula| test("M", formula.rack) }.reverse!
+            # See https://ruby-doc.org/3.2/Kernel.html#method-i-test
+            Formula.installed.sort_by { |formula| T.cast(test("M", formula.rack.to_s), Time) }.reverse!
           elsif args.full_name?
             Formula.installed.sort { |a, b| tap_and_name_comparison.call(a.full_name, b.full_name) }
           else

Library/Homebrew/cmd/missing.rb

@@ -33,7 +33,7 @@ module Homebrew
         end
 
         ff.each do |f|
-          missing = f.missing_dependencies(hide: args.hide)
+          missing = f.missing_dependencies(hide: args.hide || [])
           next if missing.empty?
 
           Homebrew.failed = true

Library/Homebrew/cmd/update-report.rb

@@ -161,7 +161,7 @@ module Homebrew
               end
               next unless formula.any_version_installed?
 
-              keg = formula.installed_kegs.last
+              keg = formula.installed_kegs.fetch(-1)
               tab = keg.tab
               # force a `brew upgrade` from the linuxbrew-core version to the homebrew-core version (even if lower)
               tab.source["versions"]["version_scheme"] = -1

Library/Homebrew/cmd/uses.rb

@@ -106,8 +106,8 @@ module Homebrew
           # We can only get here if `used_formulae_missing` is false, thus there are no UnavailableFormula.
           used_formulae = T.cast(used_formulae, T::Array[Formula])
           if show_formulae_and_casks || args.formula?
-            deps += used_formulae.map(&:runtime_installed_formula_dependents)
+            deps += T.must(used_formulae.map(&:runtime_installed_formula_dependents)
-                                 .reduce(&:&)
+                     .reduce(&:&))
                      .select(&:any_version_installed?)
           end
           if show_formulae_and_casks || args.cask?

Library/Homebrew/dev-cmd/bump.rb

@@ -115,7 +115,7 @@ module Homebrew
             end
           end
 
-          formulae_and_casks = formulae_and_casks&.sort_by do |formula_or_cask|
+          formulae_and_casks = formulae_and_casks.sort_by do |formula_or_cask|
             formula_or_cask.respond_to?(:token) ? formula_or_cask.token : formula_or_cask.name
           end
 

Library/Homebrew/diagnostic.rb

@@ -63,7 +63,7 @@ module Homebrew
         end
       end
 
-      sig { params(list: T::Array[String], string: String).returns(String) }
+      sig { params(list: T::Array[T.any(Formula, Pathname, String)], string: String).returns(String) }
       def inject_file_list(list, string)
         list.reduce(string.dup) { |acc, elem| acc << "  #{elem}\n" }
             .freeze

Library/Homebrew/extend/os/linux/cmd/update-report.rb

@@ -24,7 +24,7 @@ module Homebrew
       end
       next unless recursive_runtime_dependencies.map(&:name).include? "gcc"
 
-      keg = formula.installed_kegs.last
+      keg = formula.installed_kegs.fetch(-1)
       tab = keg.tab
       # Force reinstallation upon `brew upgrade` to fix the bottle RPATH.
       tab.source["versions"]["version_scheme"] = -1

Library/Homebrew/extend/os/linux/dependency_collector.rb

@@ -48,9 +48,9 @@ module OS
         built_global_dep_tree!
       end
 
-      sig { params(name: String).returns(T.nilable(Formula)) }
+      sig { params(name: String).returns(T.nilable(::Formula)) }
       def formula_for(name)
-        @formula_for ||= T.let({}, T.nilable(T::Hash[String, Formula]))
+        @formula_for ||= T.let({}, T.nilable(T::Hash[String, ::Formula]))
         @formula_for[name] ||= ::Formula[name]
       rescue FormulaUnavailableError
         nil

Library/Homebrew/formula_cellar_checks.rb

@@ -307,7 +307,7 @@ module FormulaCellarChecks
     return unless formula.service?
     return unless formula.service.command?
 
-    "Service command does not exist" unless File.exist?(formula.service.command.first)
+    "Service command does not exist" unless File.exist?(T.must(formula.service.command).first)
   end
 
   sig { params(formula: Formula).returns(T.nilable(String)) }

Library/Homebrew/formula_installer.rb

@@ -1230,7 +1230,7 @@ on_request: installed_on_request?, options:)
     return keg_formula_path if formula.loaded_from_api?
     return keg_formula_path if formula.local_bottle_path.present?
 
-    tap_formula_path = formula.specified_path
+    tap_formula_path = T.must(formula.specified_path)
     return keg_formula_path unless tap_formula_path.exist?
 
     begin

Library/Homebrew/language/java.rb

@@ -16,7 +16,7 @@ module Language
         next false unless f.any_version_installed?
 
         unless version.zero?
-          major = f.any_installed_version.major
+          major = T.must(f.any_installed_version).major
           next false if major < version
           next false if major > version && !can_be_newer
         end

Library/Homebrew/language/python.rb

@@ -340,7 +340,10 @@ module Language
             version = rp.match %r{^#{HOMEBREW_CELLAR}/python@(.*?)/}o
             version = "@#{version.captures.first}" unless version.nil?
 
-            new_target = rp.sub %r{#{HOMEBREW_CELLAR}/python#{version}/[^/]+}, Formula["python#{version}"].opt_prefix
+            new_target = rp.sub(
+              %r{#{HOMEBREW_CELLAR}/python#{version}/[^/]+},
+              Formula["python#{version}"].opt_prefix.to_s,
+            )
             f.unlink
             f.make_symlink new_target
           end
@@ -351,7 +354,10 @@ module Language
             version = prefix_path.match %r{^#{HOMEBREW_CELLAR}/python@(.*?)/}o
             version = "@#{version.captures.first}" unless version.nil?
 
-            prefix_path.sub! %r{^#{HOMEBREW_CELLAR}/python#{version}/[^/]+}, Formula["python#{version}"].opt_prefix
+            prefix_path.sub!(
+              %r{^#{HOMEBREW_CELLAR}/python#{version}/[^/]+},
+              Formula["python#{version}"].opt_prefix.to_s,
+            )
             prefix_file.atomic_write prefix_path
           end
 
@@ -362,7 +368,7 @@ module Language
             cfg = cfg_file.read
             framework = "Frameworks/Python.framework/Versions"
             cfg.match(%r{= *(#{HOMEBREW_CELLAR}/(python@[\d.]+)/[^/]+(?:/#{framework}/[\d.]+)?/bin)}) do |match|
-              cfg.sub! match[1].to_s, Formula[match[2]].opt_bin
+              cfg.sub! match[1].to_s, Formula[T.must(match[2])].opt_bin.to_s
               cfg_file.atomic_write cfg
             end
           end