From 8f80cc65686bd6b5eed365fd7d9f822366c01943 Mon Sep 17 00:00:00 2001
From: Mike McQuaid <mike@mikemcquaid.com>
Date: Tue, 13 Dec 2016 01:53:05 +0000
Subject: [PATCH] diagnostic: check for bad tap files.

Check for Ruby files in taps that are outside of the detected `Formula`
directory for a tap but inside one of the other potential directories.

This usually indicates a formula has been added in the wrong directory
in a tap and is used to fail CI in this case.
---
 Library/Homebrew/diagnostic.rb | 23 +++++++++++++++++++++++
 Library/Homebrew/tap.rb        |  6 +++++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index e8506ce807..64c155fde7 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -1075,6 +1075,29 @@ module Homebrew
         message
       end
 
+      def check_for_tap_ruby_files_locations
+        bad_tap_files = {}
+        Tap.each do |tap|
+          unused_formula_dirs = tap.potential_formula_dirs - [tap.formula_dir]
+          unused_formula_dirs.each do |dir|
+            next unless dir.exist?
+            dir.children.each do |path|
+              next unless path.extname == ".rb"
+              bad_tap_files[tap] ||= []
+              bad_tap_files[tap] << path
+            end
+          end
+        end
+        return if bad_tap_files.empty?
+        bad_tap_files.keys.map do |tap|
+          <<-EOS.undent
+            Found Ruby file outside #{tap} tap formula directory
+            (#{tap.formula_dir}):
+              #{bad_tap_files[tap].join("\n  ")}
+          EOS
+        end.join("\n")
+      end
+
       def all
         methods.map(&:to_s).grep(/^check_/)
       end
diff --git a/Library/Homebrew/tap.rb b/Library/Homebrew/tap.rb
index 68b21ac604..4b59f23446 100644
--- a/Library/Homebrew/tap.rb
+++ b/Library/Homebrew/tap.rb
@@ -292,7 +292,11 @@ class Tap
 
   # path to the directory of all {Formula} files for this {Tap}.
   def formula_dir
-    @formula_dir ||= [path/"Formula", path/"HomebrewFormula", path].detect(&:directory?)
+    @formula_dir ||= potential_formula_dirs.detect(&:directory?)
+  end
+
+  def potential_formula_dirs
+    @potential_formula_dirs ||= [path/"Formula", path/"HomebrewFormula", path].freeze
   end
 
   # path to the directory of all {Cask} files for this {Tap}.