Issue #16908 has been updated by jeremyevans0 (Jeremy Evans). ioquatix (Samuel Williams) wrote in #note-2: > @jeremyevans0 I agree with your assessment, however that hash does not have default_proc so I assume that it would return `nil` after all key-value pairs are `shift`ed out. That's different from invoking `default_proc` and returning `[nil, 0]`. Same principle applies when using a default_proc: ```ruby # simple hash with indifferent access hash = Hash.new{|h,k| h[k.to_s] unless k.is_a? String} hash['a'] = 1 hash['b'] = 2 while (k,v = hash.shift) p [k, v] end ``` ---------------------------------------- Bug #16908: Strange behaviour of Hash#shift when used with `default_proc`. https://bugs.ruby-lang.org/issues/16908#change-85765 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal * ruby -v: 2.7.0 * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- I don't have any strong opinion about this, but I observed the following behaviour which I thought was confusing. Maybe it's okay, or maybe we should change it to be more consistent. ``` hash = Hash.new{|k,v| k[v] = 0} hash.shift # => 0 hash.shift # => [nil, 0] ``` My feeling was, both cases should return `[nil, 0]`. -- https://bugs.ruby-lang.org/ Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>