[Sbcl-devel] Debugger unable to inspect local variables in argument call.

[lawrence m. <we...@gm...>]

If I define a function, and then call it with two few arguments,
I enter the debugger.  An attempt to inspect the locals at the
top of the stack then fails as shown below.  (Note: This seems to
look similar to Bugs 162 and 216.)

| $ sbcl --noinform --userinit /dev/null --sysinit /dev/null
| * (machine-type)

| "X86"
| * (lisp-implementation-version)

| "0.8.7.33"
| * *features*

| (:SB-THREAD :SB-SHOW-ASSEM :SB-FUTEX
|  :SB-AFTER-XC-CORE :ANSI-CL
|  :COMMON-LISP :SBCL :UNIX :SB-DOC
|  :SB-TEST :IEEE-FLOATING-POINT :X86
|  :LINUX :GENCGC :STACK-GROWS-DOWNWARD-NOT-UPWARD
|  :C-STACK-IS-CONTROL-STACK)

| * (defun foo (x y) (values x y))

| FOO
| * (foo t)

| debugger invoked on a SB-INT:SIMPLE-PROGRAM-ERROR in thread 2669:
|   invalid number of arguments: 1

| You can type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL.

| restarts (invokable by number or by possibly-abbreviated name):
|   0: [ABORT   ] Reduce debugger level (leaving debugger, returning to toplevel).
|   1: [TOPLEVEL] Restart at toplevel READ/EVAL/PRINT loop.
| ("XEP for FOO" #<error printing object>)[:EXTERNAL]
| source: (SB-INT:NAMED-LAMBDA FOO (X Y) (BLOCK FOO (VALUES X Y)))
| 0] l
| #:G3  =  1
| #:G4  =  T
| #:G5  =

| debugger invoked on a TYPE-ERROR in thread 2669:
|   The value :INVALID-OBJECT is not of type SB-KERNEL:LAYOUT.

| You can type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL.

| restarts (invokable by number or by possibly-abbreviated name):
|   0: [ABORT   ] Reduce debugger level (to debug level 1).
|   1:            Reduce debugger level (leaving debugger, returning to toplevel).
|   2: [TOPLEVEL] Restart at toplevel READ/EVAL/PRINT loop.
| (SB-PCL::CACHE-MISS-VALUES #<error printing object>)
| 0[2] 1

| * (defun bar (x) (values x))

| BAR
| * (bar)

| debugger invoked on a SB-INT:SIMPLE-PROGRAM-ERROR in thread 2669:
|   invalid number of arguments: 0

| You can type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL.

| restarts (invokable by number or by possibly-abbreviated name):
|   0: [ABORT   ] Reduce debugger level (leaving debugger, returning to toplevel).
|   1: [TOPLEVEL] Restart at toplevel READ/EVAL/PRINT loop.
| ("XEP for BAR" 0 269348568)[:EXTERNAL]
| source: (SB-INT:NAMED-LAMBDA BAR (X) (BLOCK BAR (VALUES X)))
| 0] l
| #:G4  =  0
| #:G5  =  269348568

| 0] 1

Although I can print the locals for BAR, the value of #:G5 looks
slightly suspicious, however, I'm not sure, since I'm not really
up-to-speed with the debugger.  I haven't checked to see if this
fails without :SB-THREAD, which I can do if needed.

-- 
lawrence mitchell <we...@gm...>