Question: Building websockets app based off of actioncable-examples. When starting server, running rake, etc. I keep getting the message:

```
Array values in the parameter to `Gem.paths=` are deprecated.

```

Haven't seen a solution here, but did find one. I wanted to post the question and answer here so that it's available.

Answer: 
I also face same error in my `rails 4.2.7` application and I fixed the error to update `bin/spring` file line no 11 

```
Gem.paths = { 'GEM_PATH' => [Bundler.bundle_path.to_s, *Gem.path].uniq.join(Gem.path_separator) }

```
**tl;dr** `bin/spring binstub`, you might need to update `spring` before that (if 1.3.3 <= `spring` < 1.6.4).

`spring` had been using an array for the `GEM_PATH` value in its binstubs since [1.3.3](https://github.com/rails/spring/commit/c2aafcfa0eed4bd62b971fd868bdcccebdd48407#diff-75bd83565389d1cdfbd3d56c3414272fadd7aba5e9d0a892059bce5dcaea0fabR40) till [1.6.4](https://github.com/rails/spring/commit/e31716d8654520cde26d61d271e6eca1d5c02192#diff-75bd83565389d1cdfbd3d56c3414272fadd7aba5e9d0a892059bce5dcaea0fabR41).

In `rubygems-2.6.0` they were planning to [give up on arrays](https://github.com/rubygems/rubygems/commit/27a436e91f1d83dc4a23168851d4d29a73fde752#diff-14c3102878b81a4dd5aed636d74aa3c20f7f10e8dff57cf4117b427e7dadef93L58), but apparently those binstubs made its way in a lot of projects. So they [restored the array handling](https://github.com/rubygems/rubygems/blob/v2.6.1/History.txt#L9-L10) in [`rubygems-2.6.1`](https://github.com/rubygems/rubygems/commit/a6b69e94232166dda441bbb69b64cf90562eebfd#diff-dd90140a6483cfb50fbbc3268f0d77984cd96e17792201e53bb3c0dc7ec435f9R360), but with a deprecation warning. Those 2 correspond to [Ruby 2.4.0](https://github.com/ruby/ruby/commit/5a90f9e8f84533e7859232895fc4bbe6b31cc771).