From 0606c9fd824a03dfb0ff84eff3ff7beab021edab Mon Sep 17 00:00:00 2001
From: Mike McQuaid <mike@mikemcquaid.com>
Date: Thu, 5 Nov 2020 20:33:51 +0000
Subject: [PATCH] outdated/upgrade: fix upgrade alias edge case.

If you're going to follow an alias to find the outdated formula then
ensure that the latest one isn't already installed.

Fixes https://github.com/Homebrew/homebrew-core/issues/63971
---
 Library/Homebrew/cmd/outdated.rb | 2 +-
 Library/Homebrew/cmd/upgrade.rb  | 9 ++++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/Library/Homebrew/cmd/outdated.rb b/Library/Homebrew/cmd/outdated.rb
index d5c5458ad9..623f434729 100644
--- a/Library/Homebrew/cmd/outdated.rb
+++ b/Library/Homebrew/cmd/outdated.rb
@@ -97,7 +97,7 @@ module Homebrew
         if verbose?
           outdated_kegs = f.outdated_kegs(fetch_head: args.fetch_HEAD?)
 
-          current_version = if f.alias_changed?
+          current_version = if f.alias_changed? && !f.latest_formula.latest_version_installed?
             latest = f.latest_formula
             "#{latest.name} (#{latest.pkg_version})"
           elsif f.head? && outdated_kegs.any? { |k| k.version.to_s == f.pkg_version.to_s }
diff --git a/Library/Homebrew/cmd/upgrade.rb b/Library/Homebrew/cmd/upgrade.rb
index c2ece9f42e..b7a53cbd40 100644
--- a/Library/Homebrew/cmd/upgrade.rb
+++ b/Library/Homebrew/cmd/upgrade.rb
@@ -137,7 +137,14 @@ module Homebrew
 
     pinned = outdated.select(&:pinned?)
     outdated -= pinned
-    formulae_to_install = outdated.map(&:latest_formula)
+    formulae_to_install = outdated.map do |f|
+      f_latest = f.latest_formula
+      if f_latest.latest_version_installed?
+        f
+      else
+        f_latest
+      end
+    end
 
     if !pinned.empty? && !args.ignore_pinned?
       ofail "Not upgrading #{pinned.count} pinned #{"package".pluralize(pinned.count)}:"