`brew log` works with Tapped formula

Fixes Homebrew/homebrew#12446.

1 files changed, 4 insertions, 2 deletions

diff --git a/Library/Homebrew/cmd/log.rb b/Library/Homebrew/cmd/log.rb
index ce2ef8dc7..0fc65113e 100644
--- a/Library/Homebrew/cmd/log.rb
+++ b/Library/Homebrew/cmd/log.rb
@@ -1,10 +1,12 @@
 module Homebrew extend self
   def log
-    cd HOMEBREW_REPOSITORY
     if ARGV.named.empty?
+      cd HOMEBREW_REPOSITORY
       exec "git", "log", *ARGV.options_only
     else
-      exec "git", "log", *ARGV.options_only + ARGV.formulae.map(&:path)
+      path = ARGV.formulae.first.path.realpath
+      cd path.dirname # supports taps
+      exec "git", "log", *ARGV.options_only + [path]
     end
   end
 end