The variable HUNCHENTOOT:*SESSION* is unbound.
[Condition of type UNBOUND-VARIABLE]
Restarts:
0: [RETRY] Retry SLIME REPL evaluation request.
1: [ABORT] Return to SLIME's top level.
2: [TERMINATE-THREAD] Terminate this thread (#<thread repl-thread"="" running="" {11d0d179}="">)
Backtrace:
0: (WEBLOCKS:WEBAPP-SESSION-VALUE WEBLOCKS:ROOT-WIDGET)[:EXTERNAL]
1: ((SB-PCL::FAST-METHOD WEBLOCKS:GET-WIDGETS-BY-TYPE (T)) #<unavailable argument=""> #<unavailable argument=""> CONTENTREES::PROPOSALS-VIEWER)[:EXTERNAL]
2: (SB-INT:SIMPLE-EVAL-IN-LEXENV (WEBLOCKS:GET-WIDGETS-BY-TYPE 'CONTENTREES::PROPOSALS-VIEWER) #<null-lexenv>)
3: (SWANK::EVAL-REGION "(weblocks::get-widgets-by-type 'contentrees::proposals-viewer)\n")
4: ((LAMBDA ()))
5: (SWANK::TRACK-PACKAGE #<closure (lambda="" #)="" {118ffc8d}="">)
6: (SWANK::CALL-WITH-RETRY-RESTART "Retry SLIME REPL evaluation request." #<closure (lambda="" #)="" {118ffc1d}="">)
7: (SWANK::CALL-WITH-BUFFER-SYNTAX NIL #<closure (lambda="" #)="" {118ffc05}="">)
8: (SWANK::REPL-EVAL "(weblocks::get-widgets-by-type 'contentrees::proposals-viewer)\n")
9: (SB-INT:SIMPLE-EVAL-IN-LEXENV (SWANK:LISTENER-EVAL "(weblocks::get-widgets-by-type 'contentrees::proposals-viewer)\n") #<null-lexenv>)
10: (SWANK::EVAL-FOR-EMACS (SWANK:LISTENER-EVAL "(weblocks::get-widgets-by-type 'contentrees::proposals-viewer)\n") "COMMON-LISP-USER" 31)
11: (SWANK::PROCESS-REQUESTS NIL)
12: ((LAMBDA ()))
13: ((LAMBDA (SWANK-BACKEND::HOOK SWANK-BACKEND::FUN)) #<function swank:swank-debugger-hook=""> #<closure (lambda="" #)="" {118ff645}="">)
14: (SWANK::CALL-WITH-REDIRECTED-IO #<swank::connection {11c135d9}=""> #<closure (lambda="" #)="" {118ff655}="">)
15: (SWANK::CALL-WITH-CONNECTION #<swank::connection {11c135d9}=""> #<closure (lambda="" #)="" {118ff645}="">)
16: (SWANK::HANDLE-REQUESTS #<swank::connection {11c135d9}=""> NIL)
17: (SWANK::CALL-WITH-BINDINGS NIL #<closure (lambda="" #)="" {11d0c1ad}="">)
18: ((FLET SB-THREAD::WITH-MUTEX-THUNK))
19: ((FLET #:WITHOUT-INTERRUPTS-BODY-[CALL-WITH-MUTEX]479))
20: (SB-THREAD::CALL-WITH-MUTEX ..)
21: ((LAMBDA ()))
22: ("foreign function: call_into_lisp")
23: ("foreign function: funcall0")
24: ("foreign function: new_thread_trampoline")
25: ("foreign function: _pthread_start")
26: ("foreign function: thread_start")
Saikat figured out and explained to me that I got the error because the REPL doesn't have sessions. As usual, that seems obvious in retrospect.