diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index 1651e82624..5e36ac54a3 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -191,6 +191,16 @@ case "$HOMEBREW_COMMAND" in
   --config)    HOMEBREW_COMMAND="config" ;;
 esac
 
+if [[ -z "$HOMEBREW_DEVELOPER" ]]
+then
+  export HOMEBREW_GIT_CONFIG_FILE="$HOMEBREW_REPOSITORY/.git/config"
+  HOMEBREW_GIT_CONFIG_DEVELOPERMODE="$(git config --file="$HOMEBREW_GIT_CONFIG_FILE" --get homebrew.developermode)"
+  if [[ "$HOMEBREW_GIT_CONFIG_DEVELOPERMODE" = "true" ]]
+  then
+    export HOMEBREW_DEVELOPER="1"
+  fi
+fi
+
 if [[ -f "$HOMEBREW_LIBRARY/Homebrew/cmd/$HOMEBREW_COMMAND.sh" ]]
 then
   HOMEBREW_BASH_COMMAND="$HOMEBREW_LIBRARY/Homebrew/cmd/$HOMEBREW_COMMAND.sh"