From d0e95f45f3881e2b9cda44c2a2e74aad976297df Mon Sep 17 00:00:00 2001
From: John Hawthorn <john@hawthorn.email>
Date: Thu, 1 Aug 2019 12:49:32 -0700
Subject: [PATCH] Raise TypeError instead of infinite looping

---
 .../connection_adapters/connection_specification.rb         | 2 +-
 .../test/cases/connection_specification/resolver_test.rb    | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/activerecord/lib/active_record/connection_adapters/connection_specification.rb b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
index 20041f0c85193..da41ed22b1d93 100644
--- a/activerecord/lib/active_record/connection_adapters/connection_specification.rb
+++ b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
@@ -221,7 +221,7 @@ def resolve_connection(config_or_env, pool_name = nil)
             when Hash
               resolve_hash_connection config_or_env
             else
-              resolve_connection config_or_env
+              raise TypeError, "Invalid type for configuration. Expected Symbol, String, or Hash. Got #{config_or_env.inspect}"
             end
           end
 
diff --git a/activerecord/test/cases/connection_specification/resolver_test.rb b/activerecord/test/cases/connection_specification/resolver_test.rb
index 72be14f507780..a9aaf15099c9e 100644
--- a/activerecord/test/cases/connection_specification/resolver_test.rb
+++ b/activerecord/test/cases/connection_specification/resolver_test.rb
@@ -135,6 +135,12 @@ def test_spec_name_with_inline_config
           spec = spec("adapter" => "sqlite3")
           assert_equal "primary", spec.name, "should default to primary id"
         end
+
+        def test_spec_with_invalid_type
+          assert_raises TypeError do
+            spec(Object.new)
+          end
+        end
       end
     end
   end