From a89a3dfe91faf3f53a611d048ac7dfabb9e041ec Mon Sep 17 00:00:00 2001
From: Mike McQuaid <mike@mikemcquaid.com>
Date: Wed, 22 May 2019 10:18:56 +0100
Subject: [PATCH 1/3] Use `whoami` consistently in `chown` commands

---
 Library/Homebrew/cask/cmd/doctor.rb | 2 +-
 docs/Gems,-Eggs-and-Perl-Modules.md | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Library/Homebrew/cask/cmd/doctor.rb b/Library/Homebrew/cask/cmd/doctor.rb
index ddd033a2e1..0a6a015bba 100644
--- a/Library/Homebrew/cask/cmd/doctor.rb
+++ b/Library/Homebrew/cask/cmd/doctor.rb
@@ -67,7 +67,7 @@ module Cask
 
         if path.exist? && !path.writable?
           add_error "The staging path #{user_tilde(path.to_s)} is not writable by the current user."
-          add_error "To fix, run \'sudo chown -R ${USER}:staff #{user_tilde(path.to_s)}'"
+          add_error "To fix, run \'sudo chown -R $(whoami):staff #{user_tilde(path.to_s)}'"
         end
 
         puts user_tilde(path.to_s)
diff --git a/docs/Gems,-Eggs-and-Perl-Modules.md b/docs/Gems,-Eggs-and-Perl-Modules.md
index 8fafd9655a..9b6bd42308 100644
--- a/docs/Gems,-Eggs-and-Perl-Modules.md
+++ b/docs/Gems,-Eggs-and-Perl-Modules.md
@@ -116,7 +116,7 @@ If you ever did a `sudo gem`, etc. before then a lot of files will have
 been created owned by root. Fix with:
 
 ```sh
-sudo chown -R $USER /Library/Ruby /Library/Perl /Library/Python
+sudo chown -R $(whoami) /Library/Ruby /Library/Perl /Library/Python
 ```
 
 ## Perl CPAN modules without sudo

From 8908dc51d610f2ce3b2c086b25e04cb9322a66d1 Mon Sep 17 00:00:00 2001
From: Mike McQuaid <mike@mikemcquaid.com>
Date: Wed, 22 May 2019 10:19:20 +0100
Subject: [PATCH 2/3] keg: tell people what command will remove keg.

This will work regardless of permissions.
---
 Library/Homebrew/keg.rb | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/keg.rb b/Library/Homebrew/keg.rb
index 5c509d4600..48d6feff09 100644
--- a/Library/Homebrew/keg.rb
+++ b/Library/Homebrew/keg.rb
@@ -311,7 +311,10 @@ class Keg
     remove_old_aliases
     remove_oldname_opt_record
   rescue Errno::ENOTEMPTY
-    ofail "Could not remove #{path}! Check its permissions."
+    odie <<~EOS
+      Could not remove #{name} keg! Do so manually:
+        sudo rm -rf #{path}
+    EOS
   end
 
   def unlink(mode = OpenStruct.new)

From 4759ffb88f4d4715f99cbf8431ebf8b1f1aab630 Mon Sep 17 00:00:00 2001
From: Mike McQuaid <mike@mikemcquaid.com>
Date: Fri, 24 May 2019 16:46:54 +0100
Subject: [PATCH 3/3] reinstall: handle remove/rename permission errors.

---
 Library/Homebrew/formula_installer.rb |  9 ++++++++-
 Library/Homebrew/keg.rb               |  2 +-
 Library/Homebrew/reinstall.rb         | 18 ++++++++++++++++--
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index b549b762d6..e861f38c78 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -289,7 +289,14 @@ class FormulaInstaller
       rescue Exception => e # rubocop:disable Lint/RescueException
         # any exceptions must leave us with nothing installed
         ignore_interrupts do
-          formula.prefix.rmtree if formula.prefix.directory?
+          begin
+            formula.prefix.rmtree if formula.prefix.directory?
+          rescue Errno::EACCES, Errno::ENOTEMPTY
+            odie <<~EOS
+              Could not remove #{formula.prefix.basename} keg! Do so manually:
+                sudo rm -rf #{formula.prefix}
+            EOS
+          end
           formula.rack.rmdir_if_possible
         end
         raise if ARGV.homebrew_developer? ||
diff --git a/Library/Homebrew/keg.rb b/Library/Homebrew/keg.rb
index 48d6feff09..bafea64514 100644
--- a/Library/Homebrew/keg.rb
+++ b/Library/Homebrew/keg.rb
@@ -310,7 +310,7 @@ class Keg
     remove_opt_record if optlinked?
     remove_old_aliases
     remove_oldname_opt_record
-  rescue Errno::ENOTEMPTY
+  rescue Errno::EACCES, Errno::ENOTEMPTY
     odie <<~EOS
       Could not remove #{name} keg! Do so manually:
         sudo rm -rf #{path}
diff --git a/Library/Homebrew/reinstall.rb b/Library/Homebrew/reinstall.rb
index 015fc8a468..51862302a1 100644
--- a/Library/Homebrew/reinstall.rb
+++ b/Library/Homebrew/reinstall.rb
@@ -45,12 +45,26 @@ module Homebrew
     ignore_interrupts { restore_backup(keg, keg_was_linked) }
     raise
   else
-    backup_path(keg).rmtree if backup_path(keg).exist?
+    begin
+      backup_path(keg).rmtree if backup_path(keg).exist?
+    rescue Errno::EACCES, Errno::ENOTEMPTY
+      odie <<~EOS
+        Could not remove #{backup_path(keg).parent.basename} backup keg! Do so manually:
+          sudo rm -rf #{backup_path(keg)}
+      EOS
+    end
   end
 
   def backup(keg)
     keg.unlink
-    keg.rename backup_path(keg)
+    begin
+      keg.rename backup_path(keg)
+    rescue Errno::EACCES, Errno::ENOTEMPTY
+      odie <<~EOS
+        Could not rename #{keg.name} keg! Check/fix its permissions:
+          sudo chown -R $(whoami) #{keg}
+      EOS
+    end
   end
 
   def restore_backup(keg, keg_was_linked)