Deprecate `supports_statement_cache?`

`supports_statement_cache?` was introduced in 3.1.0.beta1 (104d0b2) for
bind parameter substitution, but it is no longer used in 3.1.0.rc1
(73ff679). Originally it should respect `prepared_statements` rather
than `supports_statement_cache?` (fd39847).
One more thing, named `supports_statement_cache?` is pretty misreading.
We have `StatementCache` and `StatementPool`. However,
`supports_statement_cache?` doesn't mean `StatementCache`, but
`StatementPool` unlike its name.

https://github.com/rails/rails/blob/v5.1.0/activerecord/lib/active_record/statement_cache.rb
https://github.com/rails/rails/blob/v5.1.0/activerecord/lib/active_record/connection_adapters/statement_pool.rb

1 files changed, 5 insertions, 2 deletions

diff --git a/activerecord/test/cases/bind_parameter_test.rb b/activerecord/test/cases/bind_parameter_test.rb
index 6032aa9250..49fe219563 100644
--- a/activerecord/test/cases/bind_parameter_test.rb
+++ b/activerecord/test/cases/bind_parameter_test.rb
@@ -3,8 +3,7 @@ require "models/topic"
 require "models/author"
 require "models/post"
 
-if ActiveRecord::Base.connection.supports_statement_cache? &&
-   ActiveRecord::Base.connection.prepared_statements
+if ActiveRecord::Base.connection.prepared_statements
   module ActiveRecord
     class BindParameterTest < ActiveRecord::TestCase
       fixtures :topics, :authors, :author_addresses, :posts
@@ -66,6 +65,10 @@ if ActiveRecord::Base.connection.supports_statement_cache? &&
         assert_logs_binds(binds)
       end
 
+      def test_deprecate_supports_statement_cache
+        assert_deprecated { ActiveRecord::Base.connection.supports_statement_cache? }
+      end
+
       private
         def assert_logs_binds(binds)
           payload = {