Issue #20251 has been updated by nobu (Nobuyoshi Nakada). Status changed from Open to Feedback You need `{`/`}` to make the argument a `Hash` instead of a keyword argument. ```ruby post("/persons", {name: "John Doe"}) ``` The semantics around keyword arguments has been changed at 3.0. Ruby 2.7 or earlier worked like as you described. ---------------------------------------- Bug #20251: Wrong ArgumentError raised for hash as last parameter before keyword aguments https://bugs.ruby-lang.org/issues/20251#change-106661 * Author: phillipp (Phillipp Röll) * Status: Feedback * Priority: Normal * ruby -v: ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [x86_64-linux] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Suppose we have the following method as part of an API client: ``` def post(path, params, timeout: 30) end ``` The method is then called like this: ``` post("/persons", name: "John Doe") ``` This leads to an error message `ArgumentError: wrong number of arguments (given 1, expected 2)`. I suppose the (implicit) hash is used for keyword arguments. My expectation would be, that: 1. the Hash (passed without the brackets, but that is not needed in other cases) would be accepted as the `params` argument _or_ 2. that an `ArgumentError` would be raised with the message `ArgumentError: unknown keyword: :name` In my opinion, the first case should be what's happening, the second behaviour would be my expectation if that's not possible, because a hash without brackets can't be mixed without passing keyword arguments. Either way, starting with Ruby 3.0, the behaviour makes no sense to me anymore. -- https://bugs.ruby-lang.org/