This fixed the most glaring issue on SBCL, but annoyingly it still prints a lot of redefinition warnings, and on AllegroCL loading the swank asdf system under Slime ends up in the debugger:

No methods applicable for generic function #<STANDARD-GENERIC-FUNCTION SWANK/BACKEND:MESSAGE> with args (#<SWANK/BACKEND:COMPILER-CONDITION @ #x20ec692a>) of classes (SWANK/BACKEND:COMPILER-CONDITION) [Condition of type PROGRAM-ERROR]

Restarts: 0: [CONTINUE] Try calling it again 1: [RETRY] retry the load of /home/melisgl/.cache/common-lisp/acl-10.1-linux-x86/home/melisgl/src/slime/swank/backend.fasl 2: [SKIP] skip loading /home/melisgl/.cache/common-lisp/acl-10.1-linux-x86/home/melisgl/src/slime/swank/backend.fasl 3: [TRY-RECOMPILING] Recompile backend and try loading it again 4: [RETRY] Retry loading FASL for #<CL-SOURCE-FILE "swank" "backend" "backend">. 5: [ACCEPT] Continue, treating loading FASL for #<CL-SOURCE-FILE "swank" "backend" "backend"> as having been successful. --more--

Backtrace: 0: (CERROR "Try calling it again" PROGRAM-ERROR :FORMAT-CONTROL "No methods applicable for generic function ~s with args ~s of classes ~s" :FORMAT-ARGUMENTS ...) 1: ((METHOD NO-APPLICABLE-METHOD (T)) #<STANDARD-GENERIC-FUNCTION SWANK/BACKEND:MESSAGE> #<SWANK/BACKEND:COMPILER-CONDITION @ #x20ec692a>) 2: ((FLET #:ENSURE-GENERIC-FUNCTION-USING-CLASS--NULL EXCL::INITIAL-CHEAP-SELECT-FUNCTION) #<STANDARD-GENERIC-FUNCTION SWANK/BACKEND:MESSAGE> #<SWANK/BACKEND:COMPILER-CONDITION @ #x20ec692a>) 3: (SWANK::MAKE-COMPILER-NOTE #<SWANK/BACKEND:COMPILER-CONDITION @ #x20d809a2>) 4: ((:INTERNAL SWANK::COLLECT-NOTES 0) #<SWANK/BACKEND:COMPILER-CONDITION @ #x20d809a2>) 5: (SIGNAL SWANK/BACKEND:COMPILER-CONDITION :ORIGINAL-CONDITION #<SIMPLE-WARNING @ #x20d80c8a> :SEVERITY :WARNING ...) 6: (SWANK/ALLEGRO::SIGNAL-COMPILER-CONDITION :ORIGINAL-CONDITION #<SIMPLE-WARNING @ #x20f46cc2> :SEVERITY :WARNING :MESSAGE ...) 7: (SWANK/ALLEGRO::HANDLE-COMPILER-WARNING #<SIMPLE-WARNING @ #x20f46cc2>) 8: (SIGNAL #<SIMPLE-WARNING @ #x20f46cc2>) 9: (WARN "~\n~S, ~S was defined in ~A and is now being defined in ~A" (METHOD SWANK/BACKEND:ORIGINAL-CONDITION (SWANK/BACKEND:COMPILER-CONDITION)) :OPERATOR ..) 10: ((METHOD SHARED-INITIALIZE :AFTER (EXCL::STD-CLASS T)) #<STANDARD-CLASS SWANK/BACKEND:COMPILER-CONDITION> NIL :DIRECT-SUPERCLASSES (#<STANDARD-CLASS CONDITION>) :DIRECT-SLOTS ...) 11: ((:INTERNAL (:EFFECTIVE-METHOD 2 T NIL NIL NIL) 0) #<STANDARD-CLASS SWANK/BACKEND:COMPILER-CONDITION> NIL :DIRECT-SLOTS ..) 12: ((METHOD REINITIALIZE-INSTANCE (STANDARD-OBJECT)) #<STANDARD-CLASS SWANK/BACKEND:COMPILER-CONDITION> :DIRECT-SLOTS ..) 13: ((:INTERNAL (:EFFECTIVE-METHOD 1 T NIL NIL NIL) 0) #<STANDARD-CLASS SWANK/BACKEND:COMPILER-CONDITION> :DIRECT-SLOTS ..) 14: ((METHOD ACLMOP:ENSURE-CLASS-USING-CLASS (EXCL::CLOS-CLASS T)) #<STANDARD-CLASS SWANK/BACKEND:COMPILER-CONDITION> SWANK/BACKEND:COMPILER-CONDITION :DIRECT-SUPERCLASSES (CONDITION) :DIRECT-SLOTS ...) 15: (ACLMOP:ENSURE-CLASS SWANK/BACKEND:COMPILER-CONDITION) 16: ((:TOP-LEVEL-FORM "/home/melisgl/src/slime/swank/backend.lisp" 20716)) 17: (LOAD #P"/home/melisgl/.cache/common-lisp/acl-10.1-linux-x86/home/melisgl/src/slime/swank/backend.fasl") 18: ((:INTERNAL UIOP/LISP-BUILD:LOAD* 0)) 19: (UIOP/UTILITY:CALL-WITH-MUFFLED-CONDITIONS #<Closure (:INTERNAL UIOP/LISP-BUILD:LOAD* 0) @ #x20d40dd2> ("Overwriting already existing readtable ~S." #(#:FINALIZERS-OFF-WARNING :ASDF-FINALIZERS))) 20: (UIOP/LISP-BUILD:CALL-WITH-MUFFLED-LOADER-CONDITIONS #<Closure (:INTERNAL UIOP/LISP-BUILD:LOAD* 0) @ #x20d40dd2>) 21: (UIOP/LISP-BUILD:LOAD* #P"/home/melisgl/.cache/common-lisp/acl-10.1-linux-x86/home/melisgl/src/slime/swank/backend.fasl") 22: (ASDF/LISP-ACTION:PERFORM-LISP-LOAD-FASL #<ASDF/LISP-ACTION:LOAD-OP > #<ASDF/LISP-ACTION:CL-SOURCE-FILE "swank" "backend" "backend">) 23: ((METHOD ASDF/ACTION:PERFORM (ASDF/LISP-ACTION:LOAD-OP ASDF/LISP-ACTION:CL-SOURCE-FILE)) #<ASDF/LISP-ACTION:LOAD-OP > #<ASDF/LISP-ACTION:CL-SOURCE-FILE "swank" "backend" "backend">) 24: ((:INTERNAL (:EFFECTIVE-METHOD 2 NIL NIL NIL NIL) 0) #<ASDF/LISP-ACTION:LOAD-OP > #<ASDF/LISP-ACTION:CL-SOURCE-FILE "swank" "backend" "backend">) 25: ((METHOD ASDF/ACTION:PERFORM-WITH-RESTARTS (T T)) #<ASDF/LISP-ACTION:LOAD-OP > #<ASDF/LISP-ACTION:CL-SOURCE-FILE "swank" "backend" "backend">) 26: ((METHOD ASDF/ACTION:PERFORM-WITH-RESTARTS (ASDF/LISP-ACTION:LOAD-OP ASDF/LISP-ACTION:CL-SOURCE-FILE)) #<ASDF/LISP-ACTION:LOAD-OP > #<ASDF/LISP-ACTION:CL-SOURCE-FILE "swank" "backend" "backend">) 27: ((METHOD ASDF/ACTION:PERFORM-WITH-RESTARTS :AROUND (T T)) #<ASDF/LISP-ACTION:LOAD-OP > #<ASDF/LISP-ACTION:CL-SOURCE-FILE "swank" "backend" "backend">) 28: ((:INTERNAL (:EFFECTIVE-METHOD 2 NIL NIL T T) 0) #<ASDF/LISP-ACTION:LOAD-OP > #<ASDF/LISP-ACTION:CL-SOURCE-FILE "swank" "backend" "backend">)

On Tue, 13 Jun 2023 at 14:27, Gábor Melis mega@retes.hu wrote:

Hello

I made a merge request (https://github.com/slime/slime/pull/776) after commit dd179f4a changed the behaviour of loading the swank asdf system when swank has been loaded by swank-loader already. With dd179f4a, loading the asdf system proceeds and produces lots of redefinition warnings and also package variance warnings on SBCL. The latter made asdf:load-system fail when run under Slime.

I believe this fix is necessary to compile stuff that depends on swank via ASDF. Please consider merging it.

Cheers, Gábor