--exclude should also exclude transitive dependencies

[rzane]

Motivation

Given this gemfile:

source 'https://rubygems.org'
gem 'rspec'

The following configuration should not generate any RBI files, but it does.

gem:
  exclude:
  - rspec

This would generate RBI files for all of RSpec's transitive dependencies (e.g. rspec-core, rspec-support, rspec-mocks, rspec-expectations, diff-lcs).

Implementation

I just dropped all of the excluded gems from definition.locked_gems.dependencies.

I'm not sure if this is actually the right solution, because there's something going on with BundlerExt::AutoRequireHook.override_require_false(exclude: @excluded_gems) that I don't fully understand.

Tests

I updated the existing CLI test for the --exclude option. I've also test this against a real project, and it seems to work.

[rzane]

I realize that a potential solution would be to add all of the transitive dependencies to the exclude list. But, this becomes impractical very quickly. For example, excluding the rails gem would require you to list out ~60 dependencies.

[vinistock]

We should add a test to ensure that if two gems have the same transitive dependency, excluding one of them will not exclude the transitive dependency. For example:

foo -> actionpack
bar -> actionpack

Excluding `bar` should not exclude `actionpack` because `foo` still depends on it

I think the code is probably already handling that, but I don't know if we have a test for it.

[rzane]

This wasn't doing what it was supposed to be doing.

[rzane]

Thanks for the suggestion, @vinistock. I added a transitive dependency that is shared by an excluded gem and a gem that isn't excluded (activemodel).

[rzane]

This change preserves the existing behavior covered by this spec.

Without this change, invoking tapioca gem foo --exclude foo would fail with this error, which actually seems like pretty reasonable behavior to me. I'm not sure why you'd specify the name of a gem that you're excluding.

Error: Cannot find gem 'foo'