Merge pull request #20446 from Homebrew/copilot/fix-20427

Fix `brew upgrade` not linking newer versions when upgrade interrupted

Library/Homebrew/formula.rb

@@ -1681,7 +1681,10 @@ class Formula
         # don't consider this keg current if there's a newer formula available
         next if follow_installed_alias? && new_formula_available?
 
-        # this keg is the current version of the formula, so it's not outdated
+        # this keg is the current version of the formula, but only consider it current
+        # if it's actually linked - an unlinked current version means we're outdated
+        next if !keg.optlinked? && !keg.linked? && !pinned?
+
         current_version = true
         break
       end

Library/Homebrew/test/cmd/upgrade_spec.rb

@@ -18,6 +18,18 @@ RSpec.describe Homebrew::Cmd::UpgradeCmd do
     expect(HOMEBREW_CELLAR/"testball/0.0.1").not_to exist
   end
 
+  it "links newer version when upgrade was interrupted", :integration_test do
+    setup_test_formula "testball"
+
+    (HOMEBREW_CELLAR/"testball/0.1/foo").mkpath
+
+    expect { brew "upgrade" }.to be_a_success
+
+    expect(HOMEBREW_CELLAR/"testball/0.1").to be_a_directory
+    expect(HOMEBREW_PREFIX/"opt/testball").to be_a_symlink
+    expect(HOMEBREW_PREFIX/"var/homebrew/linked/testball").to be_a_symlink
+  end
+
   it "upgrades with asking for user prompts", :integration_test do
     setup_test_formula "testball"
     (HOMEBREW_CELLAR/"testball/0.0.1/foo").mkpath

Library/Homebrew/test/formula_spec.rb

@@ -1364,6 +1364,10 @@ RSpec.describe Formula do
 
     def setup_tab_for_prefix(prefix, options = {})
       prefix.mkpath
+
+      keg = Keg.new(prefix)
+      keg.optlink
+
       tab = Tab.empty
       tab.tabfile = prefix/AbstractTab::FILENAME
       tab.source["path"] = options[:path].to_s if options[:path]
@@ -1396,6 +1400,12 @@ RSpec.describe Formula do
       expect(f.outdated_kegs).not_to be_empty
     end
 
+    example "outdated unlinked tap installed" do
+      setup_tab_for_prefix(same_prefix)
+      Keg.new(same_prefix).remove_opt_record
+      expect(f.outdated_kegs).not_to be_empty
+    end
+
     example "outdated follow alias and alias unchanged" do
       f.follow_installed_alias = true
       f.build = setup_tab_for_prefix(same_prefix, path: alias_path)