Issue #21346 has been updated by duerst (Martin Dürst). You say "queries that might find this pattern". That seems to say that you haven't found it yet. What's the result for "Hello".ensure_suffix("o!") Is it "Helloo!", or is it "Hello!"? ---------------------------------------- Feature #21346: Introduce `String#ensure_suffix` https://bugs.ruby-lang.org/issues/21346#change-113316 * Author: matheusrich (Matheus Richard) * Status: Open ---------------------------------------- ## Problem Ensuring a string has a specific suffix or prefix is a common operation in many applications. Bundler itself uses it: https://github.com/rubygems/rubygems/blob/d409ec8b5fc647fabe30e37e17cd1ea857... Here are [GitHub search](https://github.com/search) queries that might find this pattern in other places: 1. for Ruby: `/end(?:s)?_with\?\(['"].*['"]\) \?/ lang:ruby -is:fork` 1. for Crystal (a language very similar to Ruby): `/ends_with\?\(['"].*['"]\) \?/ lang:crystal -is:fork` ## Suggested solution I believe Ruby would benefit from having a first-class method for this purpose. I suggest the `String#ensure_suffix` and `String#ensure_prefix` methods. I think these names are intuitive enough (here are 2 examples of people using `ensure` for this purpose ([1](https://github.com/boltops-tools/ufo/blob/796104fdb89163d09a58fad42add697923...), [2](https://github.com/mumuki/mumuki-domain/blob/6194089d82b1a0c8805ecba98e006de...))). I've gone ahead and implemented `String#ensure_suffix` in a [pull request](https://github.com/ruby/ruby/pull/13366) but the suggested behavior is this: ```rb "Hell".ensure_suffix("o!") # => "Hello!" "Hello!".ensure_suffix("o!") # => "Hello!" s = "Hello!" s.ensure_suffix("!").equal?(s) # => true # returns same object if already suffixed ``` -- https://bugs.ruby-lang.org/