Rails/DynamicFindBy false-positives on Gem::Specification.find_by_name

[tobypinder]

Gem::Specification.find_by_name clearly looks like ActiveRecord to this cop but isn't.

False positives are inevitable and whitelist functionality has been explained before, but given this class is in rubygems itself it would feel prudent to add Gem::Specification#find_by_name and Gem::Specification#find_by_path to a default or even hardcoded whitelist inside the cop, as I cannot think of any scenario other than a namespace collision where detecting these as activerecord is expected behaviour.

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Expected behavior

No offences found.

Actual behavior

Rails/DynamicFindBy: Use 'find_by' instead of dynamic 'find_by_name'. (Rails/DynamicFindBy)

Steps to reproduce the problem

Gem::Specification.find_by_name('loremipsum')

RuboCop version

$ rubocop -V
0.51.0 (using Parser 2.4.0.0, running on ruby 2.3.5 x86_64-linux)

[tobypinder]

I see the comments from the @koic's attempt at resolving this. Would it be possible to expand the Whitelist functionality from method to ClassName#instance_method / ClassName.class_method?

I'm admittedly not at all familiar with rubocop's internals and such an approach doesn't deal with subclasses as @koic attempted but surely the class name itself is available to the AST, and we're not particularly worried about Gem::Specification getting subclassed that much? Failing that can we whitelist whole classes under a different key?

[bbatsov]

We're in the process of moving all Rails-related functionality to a standalone library (gem) named rubocop-rails. Please, migrate this issue to its issue tracker https://github.com/rubocop-hq/rubocop-rails/issues/