# Rails' binstubs vs. Bundler binstubs

There's an incompatibility in the Rails vs Bundler-generated `bin/bundle` binstub.
Futher, other Bundler-generated binstubs (e.g., `bin/rspec`) generated by older versions of Bundler don't play well with those generated by Bundler v1.16.
  
### The Binstubs and versions.

#### bin/rspec

The older [rspec-old.rb](#file-rspec-old-rb) was generated by an older version of Bundler.
Using the `Gemfile.lock` as a guide, I'd guess it was Bundler `v1.13.7`.

The current [rspec.rb](#file-rspec-rb) was generated by Bundler `v1.16.0`.

#### bin/bundle

The older [bundle-old.rb](#file-bundle-old-rb) was generated by Rails as part of the original `rails new`, circa Dec 11, 2015.
That was Rails `v4.2.5`, and the Bundler being used then (based on the `Gemfile.lock`) was `v1.10.6`.
A new Rails `v5.1.4` will generate an identical `bin/bundle` to this one, as confirmed by `bin/rails app:update:bin`.

The current [bundle.rb](#file-bundle-rb) was generated by Bundler `v1.16.0`.

### What's a developer to do?

It's unclear, to this developer, anyhow, which `bin/bundle` we should be using?
It sure seems we need the Bundler-generated version for things to work with other Bundler-generated binstubs.
But then why do we have the Rails-generated binstubs at all?
Perhaps some advice, at least, in the Rails guides, and/or in Bundler's docs would be helpful?