Move LinkedKegs migration.

Move the `LinkedKegs` migration into `utils.rb` so it can also be called
from `brew.rb` on startup.

Library/Homebrew/brew.rb

@@ -87,6 +87,9 @@ begin
     # `Homebrew.help` never returns, except for external/unknown commands.
   end
 
+  # Migrate LinkedKegs/PinnedKegs if update didn't already do so
+  migrate_legacy_keg_symlinks_if_necessary
+
   # Uninstall old brew-cask if it's still around; we just use the tap now.
   if cmd == "cask" && (HOMEBREW_CELLAR/"brew-cask").exist?
     system(HOMEBREW_BREW_FILE, "uninstall", "--force", "brew-cask")

Library/Homebrew/cmd/update-report.rb

@@ -7,6 +7,7 @@ require "migrator"
 require "formulary"
 require "descriptions"
 require "cleanup"
+require "utils"
 
 module Homebrew
   def update_preinstall_header
@@ -168,30 +169,6 @@ module Homebrew
     end
   end
 
-  def migrate_legacy_keg_symlinks_if_necessary
-    legacy_linked_kegs = HOMEBREW_LIBRARY/"LinkedKegs"
-    return unless legacy_linked_kegs.directory?
-
-    legacy_linked_kegs.children.each do |f|
-      keg = Keg.new(f.realpath)
-      keg.unlink
-      keg.link
-    end
-    FileUtils.rm_rf legacy_linked_kegs
-
-    legacy_pinned_kegs = HOMEBREW_LIBRARY/"PinnedKegs"
-    return unless legacy_pinned_kegs.directory?
-
-    legacy_pinned_kegs.children.each do |f|
-      pin_version = Keg.new(f.realpath).version
-      formula = Formulary.factory(f.basename.to_s)
-      pin = FormulaPin.new(formula)
-      pin.unpin
-      pin.pin_at(pin_version)
-    end
-    FileUtils.rm_rf legacy_pinned_kegs
-  end
-
   def link_completions_and_docs
     return if HOMEBREW_PREFIX.to_s == HOMEBREW_REPOSITORY.to_s
     command = "brew update"

Library/Homebrew/config.rb

@@ -18,18 +18,10 @@ HOMEBREW_LIBRARY = Pathname.new(ENV["HOMEBREW_LIBRARY"])
 HOMEBREW_SHIMS_PATH = HOMEBREW_LIBRARY/"Homebrew/shims"
 
 # Where we store symlinks to currently linked kegs
-HOMEBREW_LINKED_KEGS = if (HOMEBREW_LIBRARY/"LinkedKegs").exist?
-  HOMEBREW_LIBRARY/"LinkedKegs"
-else
-  HOMEBREW_PREFIX/"var/homebrew/linked"
-end
+HOMEBREW_LINKED_KEGS = HOMEBREW_PREFIX/"var/homebrew/linked"
 
 # Where we store symlinks to currently version-pinned kegs
-HOMEBREW_PINNED_KEGS = if (HOMEBREW_LIBRARY/"PinnedKegs").exist?
-  HOMEBREW_LIBRARY/"PinnedKegs"
-else
-  HOMEBREW_PREFIX/"var/homebrew/pinned"
-end
+HOMEBREW_PINNED_KEGS = HOMEBREW_PREFIX/"var/homebrew/pinned"
 
 # Where we store lock files
 HOMEBREW_LOCK_DIR = HOMEBREW_PREFIX/"var/homebrew/locks"

Library/Homebrew/utils.rb

@@ -620,3 +620,27 @@ end
 def link_path_manpages(path, command)
   link_src_dst_dirs(path/"man", HOMEBREW_PREFIX/"share/man", command)
 end
+
+def migrate_legacy_keg_symlinks_if_necessary
+  legacy_linked_kegs = HOMEBREW_LIBRARY/"LinkedKegs"
+  return unless legacy_linked_kegs.directory?
+
+  legacy_linked_kegs.children.each do |f|
+    keg = Keg.new(f.realpath)
+    keg.unlink
+    keg.link
+  end
+  FileUtils.rm_rf legacy_linked_kegs
+
+  legacy_pinned_kegs = HOMEBREW_LIBRARY/"PinnedKegs"
+  return unless legacy_pinned_kegs.directory?
+
+  legacy_pinned_kegs.children.each do |f|
+    pin_version = Keg.new(f.realpath).version
+    formula = Formulary.factory(f.basename.to_s)
+    pin = FormulaPin.new(formula)
+    pin.unpin
+    pin.pin_at(pin_version)
+  end
+  FileUtils.rm_rf legacy_pinned_kegs
+end