require an explicit DBS for release:do

Author: mohamedhafez

Rakefile

@@ -96,6 +96,12 @@ end
 
 desc "Releasing AR-JDBC gems (use NOOP=true to disable gem pushing)"
 task 'release:do' do
+  if !ENV["DBS"] || ENV["DBS"].strip.empty?
+    puts "you must explicitly provide a DBS env var when calling release:do. An empty one will not default to 'all' " \
+           "for this command\n\n"
+    invalid_dbs!
+  end
+
   Rake::Task['build'].invoke
   Rake::Task['build:adapters'].invoke
 
@@ -135,8 +141,9 @@ def invalid_dbs!
 end
 
 def make_db_list
-ENV["DBS"] = "mysql,postgresql,sqlite3" if ENV["DBS"] == "all" || ENV["DBS"].nil? || ENV["DBS"].strip.empty?
-requested = ENV["DBS"].split(",").map(&:strip).reject(&:empty?).map(&:downcase)
+  env_dbs = ENV["DBS"]
+  env_dbs = "mysql,postgresql,sqlite3" if env_dbs == "all" || env_dbs.nil? || env_dbs.strip.empty?
+  requested = env_dbs.split(",").map(&:strip).reject(&:empty?).map(&:downcase)
   invalid_dbs! unless requested.size > 0 && requested.size <= 3 && requested == requested.uniq
 
   canonical = requested.map do |name|