⚡✅ Update more regexps to run in linear time

bin/check-regexps

@@ -0,0 +1,27 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# See also: test/net/imap/regexp_collector.rb
+# See also: test/net/imap/test_regexps.rb
+
+def traverse(m=Object, s=Set.new, &b)
+  m.constants(false).map{m.const_get _1 rescue nil}.select{_1 in Module}.each do
+    next if s.include?(_1); s << _1
+    b and b[_1]
+    traverse(_1, s, &b)
+  end
+end
+
+def collect_regexps = ObjectSpace
+  .each_object(Regexp)
+  .reject{Regexp.linear_time? _1}
+
+2.times{traverse}
+before = collect_regexps
+
+$LOAD_PATH.unshift "./lib"
+require 'net/imap'
+2.times{traverse}
+traverse(Net::IMAP) { puts _1.name }
+after = collect_regexps - before
+p before: before.count, count: after.count, after:;

lib/net/imap.rb

@@ -2443,8 +2443,8 @@ def put_string(str)
         if @debug_output_bol
           $stderr.print("C: ")
         end
-        $stderr.print(str.gsub(/\n(?!\z)/n, "\nC: "))
-        if /\r\n\z/n.match(str)
+        $stderr.print(str.gsub(/\n/n) { $'.empty? ? $& : "\nC: " })
+        if /\n\z/n.match(str)
           @debug_output_bol = true
         else
           @debug_output_bol = false