Move install-specific code to install.rb

Library/Homebrew/formula_installer.rb

@@ -344,30 +344,6 @@ class FormulaInstaller
       Homebrew::Install.perform_build_from_source_checks
     end
 
-    # not in initialize so upgrade can unlink the active keg before calling this
-    # function but after instantiating this class so that it can avoid having to
-    # relink the active keg if possible (because it is slow).
-    if formula.linked_keg.directory?
-      message = <<~EOS
-        #{formula.name} #{formula.linked_version} is already installed
-      EOS
-      if Homebrew::EnvConfig.no_install_upgrade? && formula.outdated? && !formula.head?
-        message += <<~EOS
-          To upgrade to #{formula.pkg_version}, run:
-            brew upgrade #{formula.full_name}
-        EOS
-      elsif only_deps?
-        message = nil
-      else
-        # some other version is already installed *and* linked
-        message += <<~EOS
-          To install #{formula.pkg_version}, first run:
-            brew unlink #{formula.name}
-        EOS
-      end
-      raise CannotInstallFormulaError, message if message
-    end
-
     # Warn if a more recent version of this formula is available in the tap.
     begin
       if formula.pkg_version < (v = Formulary.factory(formula.full_name, force_bottle: force_bottle?).pkg_version)

Library/Homebrew/install.rb

@@ -270,11 +270,30 @@ module Homebrew
         verbose:                    verbose,
       )
 
-      if !Homebrew::EnvConfig.no_install_upgrade? && f.outdated? && !f.head?
+      if f.linked_keg.directory?
+        if Homebrew::EnvConfig.no_install_upgrade?
+          message = <<~EOS
+            #{f.name} #{f.linked_version} is already installed
+          EOS
+          message += if f.outdated? && !f.head?
+            <<~EOS
+              To upgrade to #{f.pkg_version}, run:
+                brew upgrade #{f.full_name}
+            EOS
+          else
+            <<~EOS
+              To install #{f.pkg_version}, first run:
+                brew unlink #{f.name}
+            EOS
+          end
+          raise CannotInstallFormulaError, message unless only_deps
+        elsif f.outdated? && !f.head?
+          puts "#{f.name} #{f.linked_version} is installed but outdated"
           kegs = Upgrade.outdated_kegs(f)
           linked_kegs = kegs.select(&:linked?)
           Upgrade.print_upgrade_message(f, fi.options)
         end
+      end
 
       fi.prelude
       fi.fetch