Issue #21106 has been reported by usumerican (usumerican _). ---------------------------------------- Bug #21106: The last iteration of the rb_ary_shuffle_bang function is useless https://bugs.ruby-lang.org/issues/21106 * Author: usumerican (usumerican _) * Status: Open * ruby -v: ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +PRISM [x86_64-darwin21] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- The number of iterations in the Fischer-Yates shuffle is (N-1) times. In the following verification code, rand function is called N times. ``` class R def rand(n) puts n return 0 end end a = [1,2,3,4,5,6,7,8,9,10] puts a.shuffle(random: R.new).join(",") ``` The while conditional expression in the rb_ary_shuffle_bang function can be changed from while(n) to while(n > 1). https://github.com/ruby/ruby/blob/db02a6b3ab4cabbdf492c26dcb1929b4ef0370a1/a... -- https://bugs.ruby-lang.org/