Issue #20043 has been updated by tenderlovemaking (Aaron Patterson). File general - ruby-lang - 4 new items - Slack 2023-12-19 16-10-39.png added ko1 (Koichi Sasada) wrote in #note-3:
It seems a bug from Ruby 2.2.
I think `itself` was added in Ruby 2.2. Seems this bug is perhaps from Ruby 1.9?  Dan0042 (Daniel DeLorme) wrote in #note-4:
I didn't know about this way of using `defined?` and it's interesting to me that we can check if multiple things are defined at once.
Yes, I thought so too. I can understand the utility of `defined?([x, y, z])`, but I can't tell if that was intended? Especially considering the `x && y && z` case. Also `defined?([x, y, z])` will return "expression" if x, y, and z are defined. But `[x, y, z]` seems like an expression regardless of whether or not those are defined (the expression just might raise though). ---------------------------------------- Bug #20043: `defined?` checks for method existence but only sometimes https://bugs.ruby-lang.org/issues/20043#change-105744 * Author: tenderlovemaking (Aaron Patterson) * Status: Open * Priority: Normal * ruby -v: ruby 3.3.0dev (2023-12-05T21:25:34Z master 56eccb350b) [arm64-darwin23] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- When an expression is passed to `defined?`, it will _sometimes_ check if a method in a sub-expression is defined and sometimes it won't. For example: ``` $ ./miniruby -e'p defined?(a)' nil $ ./miniruby -e'p defined?([a])' nil ``` In the above case, Ruby will check whether or not the method `a` is defined, and it returns `nil`. However, if you use a splat, it will not check: ``` $ ./miniruby -e'p defined?([*a])' "expression" ``` The same thing seems to happen with method parameters: ``` $ ./miniruby -e'p defined?(itself)' "method" $ ./miniruby -e'p defined?(itself(a))' nil $ ./miniruby -e'p defined?(itself(*a))' "method" ``` Oddly, `defined?` will check contents of arrays, but _won't_ check contents of hashes: ``` $ ./miniruby -e'p defined?([[[[a]]]])' nil $ ./miniruby -e'p defined?({ a => a })' "expression" ``` I think all of the cases that refer to `a` should check whether or not `a` is defined regardless of splats or hashes. ---Files-------------------------------- clipboard-202312191405-owvpy.png (27.3 KB) general - ruby-lang - 4 new items - Slack 2023-12-19 16-10-39.png (100 KB) -- https://bugs.ruby-lang.org/