fetch/build formula from source when modified

closes Homebrew/homebrew#36068

Closes Homebrew/homebrew#41397.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/Library/Homebrew/cmd/fetch.rb b/Library/Homebrew/cmd/fetch.rb
index 5ac41a4d3..171218294 100644
--- a/Library/Homebrew/cmd/fetch.rb
+++ b/Library/Homebrew/cmd/fetch.rb
@@ -32,6 +32,13 @@ module Homebrew
   def fetch_bottle? f
     return true if ARGV.force_bottle? && f.bottle
     return false unless f.bottle && f.pour_bottle?
+    if f.file_modified?
+      filename = f.path.to_s.gsub("#{HOMEBREW_PREFIX}/", "")
+      opoo "Formula file is modified!"
+      puts "Fetching source because #{filename} has local changes"
+      puts "To fetch the bottle instead, run with --force-bottle"
+      return false
+    end
     return false if ARGV.build_from_source? || ARGV.build_bottle?
     return false unless f.bottle.compatible_cellar?
     return true