Out of curiosity, I went looking for the session files. It looks like the session information is getting stored, but not retrieved:
% L tmp/se*/* -rw------- 1 rdm 69 Oct 13 20:46 tmp/sessions/ruby_sess.41ab9c6e783fb448 -rw------- 1 rdm 90 Oct 13 20:46 tmp/sessions/ruby_sess.d56b9b9cb629a50c
od -cx tmp/se*/*8 0000000 004 \b { 006 " \t h a s h { 006 " \n f l 0408 7b06 2209 6861 7368 7b06 220a 666c 0000020 a s h I C : ' A c t i o n C o n 6173 6849 433a 2741 6374 696f 6e43 6f6e 0000040 t r o l l e r : : F l a s h : : 7472 6f6c 6c65 723a 3a46 6c61 7368 3a3a 0000060 F l a s h H a s h { \0 006 : \n @ u 466c 6173 6848 6173 687b 0006 3a0a 4075 0000100 s e d { \0 7365 647b 0000 0000105
% od -cx tmp/se*/*c 0000000 004 \b { 006 " \t h a s h { \b : \v f o 0408 7b06 2209 6861 7368 7b08 3a0b 666f 0000020 o z l e " \b b a r : \t u s e r i 6f7a 6c65 2208 6261 723a 0975 7365 7269 0000040 006 " \n f l a s h I C : ' A c t i 0622 0a66 6c61 7368 4943 3a27 4163 7469 0000060 o n C o n t r o l l e r : : F l 6f6e 436f 6e74 726f 6c6c 6572 3a3a 466c 0000100 a s h : : F l a s h H a s h { \0 6173 683a 3a46 6c61 7368 4861 7368 7b00 0000120 006 : \n @ u s e d { \0 063a 0a40 7573 6564 7b00 0000132