小编Dyl*_*ews的帖子

我们正在将 Rails 应用程序从 升级5.2到6.0.1，现在每当我们运行时db:schema:load --trace，都会出现以下错误。

** Invoke db:schema:load (first_time)
** Invoke db:load_config (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:load_config
** Invoke db:check_protected_environments (first_time)
** Invoke db:load_config
** Execute db:check_protected_environments
** Invoke environment
** Execute db:schema:load
rake aborted!
NoMethodError: undefined method `spec' for #<ActiveRecord::ConnectionAdapters::NullPool:0x00007fa648b78a40>
Did you mean?  inspect
/Users/Documents/vendor/ruby/2.6.0/gems/activerecord-6.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:168:in `schema_migration'
/Users/Documents/vendor/ruby/2.6.0/gems/activerecord-6.0.1/lib/active_record/schema.rb:54:in `define'
/Users/Documents/vendor/ruby/2.6.0/gems/activerecord-6.0.1/lib/active_record/schema.rb:47:in `define'
/Users/Documents/db/schema.rb:13:in `<main>'
/Users/Documents/vendor/ruby/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:54:in `load'
/Users/Documents/vendor/ruby/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:54:in `load'
/Users/Documents/vendor/ruby/2.6.0/gems/activerecord-6.0.1/lib/active_record/tasks/database_tasks.rb:328:in `load_schema'
/Users/Documents/vendor/ruby/2.6.0/gems/activerecord-6.0.1/lib/active_record/tasks/database_tasks.rb:425:in `block in load_schema_current'
/Users/Documents/vendor/ruby/2.6.0/gems/activerecord-6.0.1/lib/active_record/tasks/database_tasks.rb:479:in `block (2 levels) in …