feat: Install an unlinked formula via brew install if --overwrite…

… is passed

If the intention is to overwrite any existing links, then `brew install` should go on to install over an unlinked formula

Library/Homebrew/cmd/install.rb

@@ -289,6 +289,7 @@ def run
             only_dependencies: args.only_dependencies?,
             force:             args.force?,
             quiet:             args.quiet?,
+            overwrite:         args.overwrite?,
           )
         end
 

Library/Homebrew/install.rb

@@ -60,7 +60,8 @@ def install_formula?(
         fetch_head: false,
         only_dependencies: false,
         force: false,
-        quiet: false
+        quiet: false,
+        overwrite: false
       )
         # head-only without --HEAD is an error
         if !head && formula.stable.nil?
@@ -132,7 +133,7 @@ def install_formula?(
                 The currently linked version is: #{formula.linked_version}
               EOS
             end
-          elsif only_dependencies
+          elsif only_dependencies || (!formula.linked? && overwrite)
             msg = nil
             return true
           elsif !formula.linked? || formula.keg_only?

Library/Homebrew/test/cmd/install_spec.rb

@@ -1,9 +1,9 @@
+# typed: false
 # frozen_string_literal: true
 
-require "cmd/install"
 require "cmd/shared_examples/args_parse"
 
-RSpec.describe Homebrew::Cmd::InstallCmd do
+describe "brew install" do
   it_behaves_like "parseable arguments"
 
   it "installs formulae", :integration_test do
@@ -45,7 +45,7 @@
     repo_path.join("bin").mkpath
 
     repo_path.cd do
-      system "git", "-c", "init.defaultBranch=master", "init"
+      system "git", "init"
       system "git", "remote", "add", "origin", "https://github.com/Homebrew/homebrew-foo"
       FileUtils.touch "bin/something.bin"
       FileUtils.touch "README"
@@ -72,16 +72,4 @@ def install
       .and be_a_success
     expect(HOMEBREW_CELLAR/"testball1/HEAD-d5eb689/foo/test").not_to be_a_file
   end
-
-  it "installs formulae with debug symbols", :integration_test do
-    setup_test_formula "testball1"
-
-    expect { brew "install", "testball1", "--debug-symbols", "--build-from-source" }
-      .to output(%r{#{HOMEBREW_CELLAR}/testball1/0\.1}o).to_stdout
-      .and not_to_output.to_stderr
-      .and be_a_success
-    expect(HOMEBREW_CELLAR/"testball1/0.1/bin/test").to be_a_file
-    expect(HOMEBREW_CELLAR/"testball1/0.1/bin/test.dSYM/Contents/Resources/DWARF/test").to be_a_file if OS.mac?
-    expect(HOMEBREW_CACHE/"Sources/testball1").to be_a_directory
-  end
 end