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Diffstat (limited to 'doc/development/ruby3_gotchas.md')
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diff --git a/doc/development/ruby3_gotchas.md b/doc/development/ruby3_gotchas.md index e4ed5039e3c..1ab7a06be24 100644 --- a/doc/development/ruby3_gotchas.md +++ b/doc/development/ruby3_gotchas.md @@ -138,3 +138,28 @@ installed Ruby manually or via tools like `asdf`. Users of the `gitlab-developme are also affected by this problem. Build images are not affected because they include the patch set addressing this bug. + +## Deprecations are not caught in DeprecationToolkit if the method is stubbed + +We rely on `deprecation_toolkit` to fail fast when using functionality that is deprecated in Ruby 2 and removed in Ruby 3. +A common issue caught during the transition from Ruby 2 to Ruby 3 relates to +the [separation of positional and keyword arguments in Ruby 3.0](https://www.ruby-lang.org/en/news/2019/12/12/separation-of-positional-and-keyword-arguments-in-ruby-3-0/). + +Unfortunately, if the author has stubbed such methods in tests, deprecations would not be caught. +We run automated detection for this warning in tests via `deprecation_toolkit`, +but it relies on the fact that `Kernel#warn` emits a warning, so stubbing out this call will effectively remove the call to warn, which means `deprecation_toolkit` will never see the deprecation warnings. +Stubbing out the implementation removes that warning, and we never pick it up, so the build is green. + +Please refer to [issue 364099](https://gitlab.com/gitlab-org/gitlab/-/issues/364099) for more context. + +## Testing in `irb` and `rails console` + +Another pitfall is that testing in `irb`/`rails c` silences the deprecation warning, +since `irb` in Ruby 2.7.x has a [bug](https://bugs.ruby-lang.org/issues/17377) that prevents deprecation warnings from showing. + +When writing code and performing code reviews, pay extra attention to method calls of the form `f({k: v})`. +This is valid in Ruby 2 when `f` takes either a `Hash` or keyword arguments, but Ruby 3 only considers this valid if `f` takes a `Hash`. +For Ruby 3 compliance, this should be changed to one of the following invocations if `f` takes keyword arguments: + +- `f(**{k: v})` +- `f(k: v)` |